1
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Haug T, Kim MS. Generalization of Quantum Machine Learning Models Using Quantum Fisher Information Metric. PHYSICAL REVIEW LETTERS 2024; 133:050603. [PMID: 39159110 DOI: 10.1103/physrevlett.133.050603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/27/2024] [Accepted: 07/03/2024] [Indexed: 08/21/2024]
Abstract
Generalization is the ability of machine learning models to make accurate predictions on new data by learning from training data. However, understanding generalization of quantum machine learning models has been a major challenge. Here, we introduce the data quantum Fisher information metric (DQFIM). It describes the capacity of variational quantum algorithms depending on variational ansatz, training data, and their symmetries. We apply the DQFIM to quantify circuit parameters and training data needed to successfully train and generalize. Using the dynamical Lie algebra, we explain how to generalize using a low number of training states. Counterintuitively, breaking symmetries of the training data can help to improve generalization. Finally, we find that out-of-distribution generalization, where training and testing data are drawn from different data distributions, can be better than using the same distribution. Our work provides a useful framework to explore the power of quantum machine learning models.
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2
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Jones JA. Controlling NMR spin systems for quantum computation. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2024; 140-141:49-85. [PMID: 38705636 DOI: 10.1016/j.pnmrs.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 05/07/2024]
Abstract
Nuclear magnetic resonance is arguably both the best available quantum technology for implementing simple quantum computing experiments and the worst technology for building large scale quantum computers that has ever been seriously put forward. After a few years of rapid growth, leading to an implementation of Shor's quantum factoring algorithm in a seven-spin system, the field started to reach its natural limits and further progress became challenging. Rather than pursuing more complex algorithms on larger systems, interest has now largely moved into developing techniques for the precise and efficient manipulation of spin states with the aim of developing methods that can be applied in other more scalable technologies and within conventional NMR. However, the user friendliness of NMR implementations means that they remain popular for proof-of-principle demonstrations of simple quantum information protocols.
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Affiliation(s)
- Jonathan A Jones
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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3
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Aerts A, Jolly SW, Kockaert P, Gorza SP, Auwera JV, Vaeck N. Modulated super-Gaussian laser pulse to populate a dark rovibrational state of acetylene. J Chem Phys 2023; 159:084303. [PMID: 37638622 DOI: 10.1063/5.0160526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/10/2023] [Indexed: 08/29/2023] Open
Abstract
A pulse-shaping technique in the mid-infrared spectral range based on pulses with a super-Gaussian temporal profile is considered for laser control. We show a realistic and efficient path to the population of a dark rovibrational state in acetylene (C2H2). The laser-induced dynamics in C2H2 are simulated using fully experimental structural parameters. Indeed, the rotation-vibration energy structure, including anharmonicities, is defined by the global spectroscopic Hamiltonian for the ground electronic state of C2H2 built from the extensive high-resolution spectroscopy studies on the molecule, transition dipole moments from intensities, and the effects of the (inelastic) collisions that are parameterized from line broadenings using the relaxation matrix [A. Aerts, J. Vander Auwera, and N. Vaeck, J. Chem. Phys. 154, 144308 (2021)]. The approach, based on an effective Hamiltonian, outperforms today's ab initio computations both in terms of accuracy and computational cost for this class of molecules. With such accuracy, the Hamiltonian permits studying the inner mechanism of theoretical pulse shaping [A. Aerts et al., J. Chem. Phys. 156, 084302 (2022)] for laser quantum control. Here, the generated control pulse presents a number of interferences that take advantage of the control mechanism to populate the dark state. An experimental setup is proposed for in-laboratory investigation.
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Affiliation(s)
- Antoine Aerts
- Université Libre de Bruxelles, Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), 50 Avenue F. Roosevelt, C.P. 160/09, Brussels 1050, Belgium
| | - Spencer W Jolly
- Université Libre de Bruxelles, OPERA-Photonique, 50 Avenue F. Roosevelt, C.P. 194/05, Brussels 1050, Belgium
| | - Pascal Kockaert
- Université Libre de Bruxelles, OPERA-Photonique, 50 Avenue F. Roosevelt, C.P. 194/05, Brussels 1050, Belgium
| | - Simon-Pierre Gorza
- Université Libre de Bruxelles, OPERA-Photonique, 50 Avenue F. Roosevelt, C.P. 194/05, Brussels 1050, Belgium
| | - Jean Vander Auwera
- Université Libre de Bruxelles, Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), 50 Avenue F. Roosevelt, C.P. 160/09, Brussels 1050, Belgium
| | - Nathalie Vaeck
- Université Libre de Bruxelles, Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), 50 Avenue F. Roosevelt, C.P. 160/09, Brussels 1050, Belgium
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4
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Singh K, Bradley CE, Anand S, Ramesh V, White R, Bernien H. Mid-circuit correction of correlated phase errors using an array of spectator qubits. Science 2023:eade5337. [PMID: 37228222 DOI: 10.1126/science.ade5337] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
Scaling up invariably error-prone quantum processors is a formidable challenge. Although quantum error correction ultimately promises fault-tolerant operation, the required qubit overhead and error thresholds are daunting. In a complementary proposal, co-located, auxiliary 'spectator' qubits act as in-situ probes of noise, and enable real-time, coherent corrections of data qubit errors. We use an array of cesium spectator qubits to correct correlated phase errors on an array of rubidium data qubits. By combining in-sequence readout, data processing, and feed-forward operations, these correlated errors are suppressed within the execution of the quantum circuit. The protocol is broadly applicable to quantum information platforms, and establishes key tools for scaling neutral-atom quantum processors: mid-circuit readout of atom arrays, real-time processing and feed-forward, and coherent mid-circuit reloading of atomic qubits.
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Affiliation(s)
- K Singh
- Intelligence Community Postdoctoral Research Fellowship Program, Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - C E Bradley
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - S Anand
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - V Ramesh
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - R White
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - H Bernien
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
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5
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Rabitz H, Russell B, Ho TS. The Surprising Ease of Finding Optimal Solutions for Controlling Nonlinear Phenomena in Quantum and Classical Complex Systems. J Phys Chem A 2023; 127:4224-4236. [PMID: 37142303 DOI: 10.1021/acs.jpca.3c01896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This Perspective addresses the often observed surprising ease of achieving optimal control of nonlinear phenomena in quantum and classical complex systems. The circumstances involved are wide-ranging, with scenarios including manipulation of atomic scale processes, maximization of chemical and material properties or synthesis yields, Nature's optimization of species' populations by natural selection, and directed evolution. Natural evolution will mainly be discussed in terms of laboratory experiments with microorganisms, and the field is also distinct from the other domains where a scientist specifies the goal(s) and oversees the control process. We use the word "control" in reference to all of the available variables, regardless of the circumstance. The empirical observations on the ease of achieving at least good, if not excellent, control in diverse domains of science raise the question of why this occurs despite the generally inherent complexity of the systems in each scenario. The key to addressing the question lies in examining the associated control landscape, which is defined as the optimization objective as a function of the control variables that can be as diverse as the phenomena under consideration. Controls may range from laser pulses, chemical reagents, chemical processing conditions, out to nucleic acids in the genome and more. This Perspective presents a conjecture, based on present findings, that the systematics of readily finding good outcomes from controlled phenomena may be unified through consideration of control landscapes with the same common set of three underlying assumptions─the existence of an optimal solution, the ability for local movement on the landscape, and the availability of sufficient control resources─whose validity needs assessment in each scenario. In practice, many cases permit using myopic gradient-like algorithms while other circumstances utilize algorithms having some elements of stochasticity or introduced noise, depending on whether the landscape is locally smooth or rough. The overarching observation is that only relatively short searches are required despite the common high dimensionality of the available controls in typical scenarios.
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Affiliation(s)
- Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Benjamin Russell
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tak-San Ho
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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6
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Wei YC, Hsu LY. Cavity-Free Quantum-Electrodynamic Electron Transfer Reactions. J Phys Chem Lett 2022; 13:9695-9702. [PMID: 36219782 DOI: 10.1021/acs.jpclett.2c02379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Richard Feynman stated that "The theory behind chemistry is quantum electrodynamics". However, harnessing quantum-electrodynamic (QED) effects to modify chemical reactions is a grand challenge and currently has only been reported in experiments using cavities due to the limitation of strong light-matter coupling. In this article, we demonstrate that QED effects can significantly enhance the rate of electron transfer (ET) by several orders of magnitude in the absence of cavities, which is implicitly supported by experimental reports. To understand how cavity-free QED effects are involved in ET reactions, we incorporate the effect of infinite one-photon states into Marcus theory, derive an explicit expression for the rate of radiative ET, and develop the concept of "electron transfer overlap". Moreover, QED effects may lead to a barrier-free ET reaction whose rate is dependent on the energy-gap power law. This study thus provides new insights into fundamental chemical principles, with promising prospects for QED-based chemical reactions.
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Affiliation(s)
- Yu-Chen Wei
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei10617, Taiwan
- Department of Chemistry, National Taiwan University, Taipei10617, Taiwan
| | - Liang-Yan Hsu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei10617, Taiwan
- Department of Chemistry, National Taiwan University, Taipei10617, Taiwan
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7
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Müller MM, Said RS, Jelezko F, Calarco T, Montangero S. One decade of quantum optimal control in the chopped random basis. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:076001. [PMID: 35605567 DOI: 10.1088/1361-6633/ac723c] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The chopped random basis (CRAB) ansatz for quantum optimal control has been proven to be a versatile tool to enable quantum technology applications such as quantum computing, quantum simulation, quantum sensing, and quantum communication. Its capability to encompass experimental constraints-while maintaining an access to the usually trap-free control landscape-and to switch from open-loop to closed-loop optimization (including with remote access-or RedCRAB) is contributing to the development of quantum technology on many different physical platforms. In this review article we present the development, the theoretical basis and the toolbox for this optimization algorithm, as well as an overview of the broad range of different theoretical and experimental applications that exploit this powerful technique.
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Affiliation(s)
- Matthias M Müller
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
| | - Ressa S Said
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Fedor Jelezko
- Institute for Quantum Optics & Center for Integrated Quantum Science and Technology, Universität Ulm, D-89081 Germany
| | - Tommaso Calarco
- Peter Grünberg Institute-Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, D-52425 Germany
- Institute for Theoretical Physics, University of Cologne, D-50937 Germany
| | - Simone Montangero
- Dipartimento di Fisica e Astronomia 'G. Galilei', Università degli Studi di Padova & INFN, Sezione di Padova, I-35131 Italy
- Padua Quantum Technology Center, Università degli Studi di Padova, I-35131 Italy
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8
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Haug T, Mok WK, You JB, Zhang W, Eng Png C, Kwek LC. Classifying global state preparation via deep reinforcement learning. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2021. [DOI: 10.1088/2632-2153/abc81f] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Quantum information processing often requires the preparation of arbitrary quantum states, such as all the states on the Bloch sphere for two-level systems. While numerical optimization can prepare individual target states, they lack the ability to find general control protocols that can generate many different target states. Here, we demonstrate global quantum control by preparing a continuous set of states with deep reinforcement learning. The protocols are represented using neural networks, which automatically groups the protocols into similar types, which could be useful for finding classes of protocols and extracting physical insights. As application, we generate arbitrary superposition states for the electron spin in complex multi-level nitrogen-vacancy centers, revealing classes of protocols characterized by specific preparation timescales. Our method could help improve control of near-term quantum computers, quantum sensing devices and quantum simulations.
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9
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Head-Marsden K, Flick J, Ciccarino CJ, Narang P. Quantum Information and Algorithms for Correlated Quantum Matter. Chem Rev 2020; 121:3061-3120. [PMID: 33326218 DOI: 10.1021/acs.chemrev.0c00620] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Discoveries in quantum materials, which are characterized by the strongly quantum-mechanical nature of electrons and atoms, have revealed exotic properties that arise from correlations. It is the promise of quantum materials for quantum information science superimposed with the potential of new computational quantum algorithms to discover new quantum materials that inspires this Review. We anticipate that quantum materials to be discovered and developed in the next years will transform the areas of quantum information processing including communication, storage, and computing. Simultaneously, efforts toward developing new quantum algorithmic approaches for quantum simulation and advanced calculation methods for many-body quantum systems enable major advances toward functional quantum materials and their deployment. The advent of quantum computing brings new possibilities for eliminating the exponential complexity that has stymied simulation of correlated quantum systems on high-performance classical computers. Here, we review new algorithms and computational approaches to predict and understand the behavior of correlated quantum matter. The strongly interdisciplinary nature of the topics covered necessitates a common language to integrate ideas from these fields. We aim to provide this common language while weaving together fields across electronic structure theory, quantum electrodynamics, algorithm design, and open quantum systems. Our Review is timely in presenting the state-of-the-art in the field toward algorithms with nonexponential complexity for correlated quantum matter with applications in grand-challenge problems. Looking to the future, at the intersection of quantum information science and algorithms for correlated quantum matter, we envision seminal advances in predicting many-body quantum states and describing excitonic quantum matter and large-scale entangled states, a better understanding of high-temperature superconductivity, and quantifying open quantum system dynamics.
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Affiliation(s)
- Kade Head-Marsden
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Johannes Flick
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
| | - Christopher J Ciccarino
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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10
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Dong D, Xing X, Ma H, Chen C, Liu Z, Rabitz H. Learning-Based Quantum Robust Control: Algorithm, Applications, and Experiments. IEEE TRANSACTIONS ON CYBERNETICS 2020; 50:3581-3593. [PMID: 31295133 DOI: 10.1109/tcyb.2019.2921424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Robust control design for quantum systems has been recognized as a key task in quantum information technology, molecular chemistry, and atomic physics. In this paper, an improved differential evolution algorithm, referred to as multiple-samples and mixed-strategy DE (msMS_DE), is proposed to search robust fields for various quantum control problems. In msMS_DE, multiple samples are used for fitness evaluation and a mixed strategy is employed for the mutation operation. In particular, the msMS_DE algorithm is applied to the control problems of: 1) open inhomogeneous quantum ensembles and 2) the consensus goal of a quantum network with uncertainties. Numerical results are presented to demonstrate the excellent performance of the improved machine learning algorithm for these two classes of quantum robust control problems. Furthermore, msMS_DE is experimentally implemented on femtosecond (fs) laser control applications to optimize two-photon absorption and control fragmentation of the molecule CH2BrI. The experimental results demonstrate the excellent performance of msMS_DE in searching for effective fs laser pulses for various tasks.
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11
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Namba T, Yoshida M, Ohtsuki Y. Machine-learning approach for constructing control landscape maps of three-dimensional alignment of asymmetric-top molecules. J Chem Phys 2020; 153:024120. [DOI: 10.1063/5.0012303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Tomotaro Namba
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Masataka Yoshida
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Yukiyoshi Ohtsuki
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
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12
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McCaul G, Orthodoxou C, Jacobs K, Booth GH, Bondar DI. Driven Imposters: Controlling Expectations in Many-Body Systems. PHYSICAL REVIEW LETTERS 2020; 124:183201. [PMID: 32441975 DOI: 10.1103/physrevlett.124.183201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/20/2020] [Accepted: 03/02/2020] [Indexed: 06/11/2023]
Abstract
We present a framework for controlling the observables of a general correlated electron system driven by an incident laser field. The approach provides a prescription for the driving required to generate an arbitrary predetermined evolution for the expectation value of a chosen observable, together with a constraint on the maximum size of this expectation. To demonstrate this, we determine the laser fields required to exactly control the current in a Fermi-Hubbard system under a range of model parameters, fully controlling the nonlinear high-harmonic generation and optically observed electron dynamics in the system. This is achieved for both the uncorrelated metalliclike state and deep in the strongly correlated Mott insulating regime, flipping the optical responses of the two systems so as to mimic the other, creating "driven imposters." We also present a general framework for the control of other dynamical variables, opening a new route for the design of driven materials with customized properties.
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Affiliation(s)
- Gerard McCaul
- Tulane University, New Orleans, Louisiana 70118, USA
| | | | - Kurt Jacobs
- U.S. Army Research Laboratory, Computational and Information Sciences Directorate, Adelphi, Maryland 20783, USA
- Department of Physics, University of Massachusetts at Boston, Boston, Massachusetts 02125, USA
- Hearne Institute for Theoretical Physics, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - George H Booth
- Department of Physics, King's College London, Strand, London, WC2R 2LS, United Kingdom
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13
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Chung H, Miller OD. High-NA achromatic metalenses by inverse design. OPTICS EXPRESS 2020; 28:6945-6965. [PMID: 32225932 DOI: 10.1364/oe.385440] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We use inverse design to discover metalens structures that exhibit broadband, achromatic focusing across low, moderate, and high numerical apertures. We show that standard unit-cell approaches cannot achieve high-efficiency high-NA focusing, even at a single frequency, due to the incompleteness of the unit-cell basis, and we provide computational upper bounds on their maximum efficiencies. At low NA, our devices exhibit the highest theoretical efficiencies to date. At high NA-of 0.9 with translation-invariant films and of 0.99 with "freeform" structures-our designs are the first to exhibit achromatic high-NA focusing.
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14
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Haine SA, Hope JJ. Machine-Designed Sensor to Make Optimal Use of Entanglement-Generating Dynamics for Quantum Sensing. PHYSICAL REVIEW LETTERS 2020; 124:060402. [PMID: 32109102 DOI: 10.1103/physrevlett.124.060402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
We use machine optimization to develop a quantum sensing scheme that achieves significantly better sensitivity than traditional schemes with the same quantum resources. Utilizing one-axis twisting dynamics to generate quantum entanglement, we find that, rather than dividing the temporal resources into separate "state-preparation" and "interrogation" stages, a complicated machine-designed sequence of rotations allows for the generation of metrologically useful entanglement while the parameter is interrogated. This provides much higher sensitivities for a given total time compared to states generated via traditional one-axis twisting schemes. This approach could be applied to other methods of generating quantum-enhanced states, allowing for atomic clocks, magnetometers, and inertial sensors with increased sensitivities.
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Affiliation(s)
- Simon A Haine
- Department of Quantum Science, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Joseph J Hope
- Department of Quantum Science, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
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15
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Abstract
In laboratory and numerical experiments, physical quantities are known with a finite precision and described by rational numbers. Based on this, we deduce that quantum control problems both for open and closed systems are in general not algorithmically solvable, i.e., there is no algorithm that can decide whether dynamics of an arbitrary quantum system can be manipulated by accessible external interactions (coherent or dissipative) such that a chosen target reaches a desired value. This conclusion holds even for the relaxed requirement of the target only approximately attaining the desired value. These findings do not preclude an algorithmic solvability for a particular class of quantum control problems. Moreover, any quantum control problem can be made algorithmically solvable if the set of accessible interactions (i.e., controls) is rich enough. To arrive at these results, we develop a technique based on establishing the equivalence between quantum control problems and Diophantine equations, which are polynomial equations with integer coefficients and integer unknowns. In addition to proving uncomputability, this technique allows to construct quantum control problems belonging to different complexity classes. In particular, an example of the control problem involving a two-mode coherent field is shown to be NP-hard, contradicting a widely held believe that two-body problems are easy.
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16
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Joe-Wong C, Ho TS, Rabitz H. Assessing the structure of classical molecular optimal control landscapes. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.110504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Voznyuk O, Jochim B, Zohrabi M, Broin A, Averin R, Carnes KD, Ben-Itzhak I, Wells E. Adaptive strong-field control of vibrational population in NO 2+. J Chem Phys 2019; 151:124310. [DOI: 10.1063/1.5115504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- O. Voznyuk
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - Bethany Jochim
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - M. Zohrabi
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Adam Broin
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - R. Averin
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - K. D. Carnes
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - I. Ben-Itzhak
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - E. Wells
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
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18
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Freeze JG, Kelly HR, Batista VS. Search for Catalysts by Inverse Design: Artificial Intelligence, Mountain Climbers, and Alchemists. Chem Rev 2019; 119:6595-6612. [PMID: 31059236 DOI: 10.1021/acs.chemrev.8b00759] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In silico catalyst design is a grand challenge of chemistry. Traditional computational approaches have been limited by the need to compute properties for an intractably large number of possible catalysts. Recently, inverse design methods have emerged, starting from a desired property and optimizing a corresponding chemical structure. Techniques used for exploring chemical space include gradient-based optimization, alchemical transformations, and machine learning. Though the application of these methods to catalysis is in its early stages, further development will allow for robust computational catalyst design. This review provides an overview of the evolution of inverse design approaches and their relevance to catalysis. The strengths and limitations of existing techniques are highlighted, and suggestions for future research are provided.
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Affiliation(s)
- Jessica G Freeze
- Department of Chemistry , Yale University , New Haven , Connecticut 06520 , United States.,Energy Sciences Institute , Yale University , West Haven , Connecticut 06516 , United States
| | - H Ray Kelly
- Department of Chemistry , Yale University , New Haven , Connecticut 06520 , United States.,Energy Sciences Institute , Yale University , West Haven , Connecticut 06516 , United States
| | - Victor S Batista
- Energy Sciences Institute , Yale University , West Haven , Connecticut 06516 , United States.,Department of Chemistry , Yale University , P.O. Box 208107 , New Haven , Connecticut 06520 , United States
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19
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Day AGR, Bukov M, Weinberg P, Mehta P, Sels D. Glassy Phase of Optimal Quantum Control. PHYSICAL REVIEW LETTERS 2019; 122:020601. [PMID: 30720331 DOI: 10.1103/physrevlett.122.020601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Indexed: 06/09/2023]
Abstract
We study the problem of preparing a quantum many-body system from an initial to a target state by optimizing the fidelity over the family of bang-bang protocols. We present compelling numerical evidence for a universal spin-glasslike transition controlled by the protocol time duration. The glassy critical point is marked by a proliferation of protocols with close-to-optimal fidelity and with a true optimum that appears exponentially difficult to locate. Using a machine learning (ML) inspired framework based on the manifold learning algorithm t-distributed stochastic neighbor embedding, we are able to visualize the geometry of the high-dimensional control landscape in an effective low-dimensional representation. Across the transition, the control landscape features an exponential number of clusters separated by extensive barriers, which bears a strong resemblance with replica symmetry breaking in spin glasses and random satisfiability problems. We further show that the quantum control landscape maps onto a disorder-free classical Ising model with frustrated nonlocal, multibody interactions. Our work highlights an intricate but unexpected connection between optimal quantum control and spin glass physics, and shows how tools from ML can be used to visualize and understand glassy optimization landscapes.
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Affiliation(s)
- Alexandre G R Day
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - Marin Bukov
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Phillip Weinberg
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - Pankaj Mehta
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
| | - Dries Sels
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA
- Theory of Quantum and Complex Systems, Universiteit Antwerpen, B-2610 Antwerpen, Belgium
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20
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Remote optimization of an ultracold atoms experiment by experts and citizen scientists. Proc Natl Acad Sci U S A 2018; 115:E11231-E11237. [PMID: 30413625 PMCID: PMC6275530 DOI: 10.1073/pnas.1716869115] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The emerging field of gamified citizen science continually probes the fault line between human and artificial intelligence. A better understanding of citizen scientists’ search strategies may lead to cognitive insights and provide inspiration for algorithmic improvements. Our project remotely engages both the general public and experts in the real-time optimization of an experimental laboratory setting. In this citizen science project the game and data acquisition are designed as a social science experiment aimed at extracting the collective search behavior of the players. A further understanding of these human skills will be a crucial challenge in the coming years, as hybrid intelligence solutions are pursued in corporate and research environments. We introduce a remote interface to control and optimize the experimental production of Bose–Einstein condensates (BECs) and find improved solutions using two distinct implementations. First, a team of theoreticians used a remote version of their dressed chopped random basis optimization algorithm (RedCRAB), and second, a gamified interface allowed 600 citizen scientists from around the world to participate in real-time optimization. Quantitative studies of player search behavior demonstrated that they collectively engage in a combination of local and global searches. This form of multiagent adaptive search prevents premature convergence by the explorative behavior of low-performing players while high-performing players locally refine their solutions. In addition, many successful citizen science games have relied on a problem representation that directly engaged the visual or experiential intuition of the players. Here we demonstrate that citizen scientists can also be successful in an entirely abstract problem visualization. This is encouraging because a much wider range of challenges could potentially be opened to gamification in the future.
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21
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Eiles MT, Tong Z, Greene CH. Theoretical Prediction of the Creation and Observation of a Ghost Trilobite Chemical Bond. PHYSICAL REVIEW LETTERS 2018; 121:113203. [PMID: 30265124 DOI: 10.1103/physrevlett.121.113203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The "trilobite"-type of molecule, predicted in 2000 and observed experimentally in 2015, arises when a Rydberg electron exerts a weak attractive force on a neutral ground state atom. Such molecules have bond lengths exceeding 100 nm. The ultralong-range chemical bond between the two atoms is a nonperturbative linear combination of the many degenerate electronic states associated with high principal quantum numbers, and the resulting electron probability distribution closely resembles a fossil trilobite from antiquity. We show how to coherently engineer this same long-range orbital through a sequence of electric and magnetic field pulses even when the ground-state atom is not present and propose several methods to observe the resulting orbital. The existence of such a ghost chemical bond in which an electron reaches out from one atom to a nonexistent second atom is a consequence of the high level degeneracy.
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Affiliation(s)
- Matthew T Eiles
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Zhengjia Tong
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Chris H Greene
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Quantum Center, Purdue University, West Lafayette, Indiana 47907, USA
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22
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Dunjko V, Briegel HJ. Machine learning & artificial intelligence in the quantum domain: a review of recent progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:074001. [PMID: 29504942 DOI: 10.1088/1361-6633/aab406] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum information technologies, on the one hand, and intelligent learning systems, on the other, are both emergent technologies that are likely to have a transformative impact on our society in the future. The respective underlying fields of basic research-quantum information versus machine learning (ML) and artificial intelligence (AI)-have their own specific questions and challenges, which have hitherto been investigated largely independently. However, in a growing body of recent work, researchers have been probing the question of the extent to which these fields can indeed learn and benefit from each other. Quantum ML explores the interaction between quantum computing and ML, investigating how results and techniques from one field can be used to solve the problems of the other. Recently we have witnessed significant breakthroughs in both directions of influence. For instance, quantum computing is finding a vital application in providing speed-ups for ML problems, critical in our 'big data' world. Conversely, ML already permeates many cutting-edge technologies and may become instrumental in advanced quantum technologies. Aside from quantum speed-up in data analysis, or classical ML optimization used in quantum experiments, quantum enhancements have also been (theoretically) demonstrated for interactive learning tasks, highlighting the potential of quantum-enhanced learning agents. Finally, works exploring the use of AI for the very design of quantum experiments and for performing parts of genuine research autonomously, have reported their first successes. Beyond the topics of mutual enhancement-exploring what ML/AI can do for quantum physics and vice versa-researchers have also broached the fundamental issue of quantum generalizations of learning and AI concepts. This deals with questions of the very meaning of learning and intelligence in a world that is fully described by quantum mechanics. In this review, we describe the main ideas, recent developments and progress in a broad spectrum of research investigating ML and AI in the quantum domain.
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Affiliation(s)
- Vedran Dunjko
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck 6020, Austria. Max Planck Institute of Quantum Optics, Garching 85748, Germany
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23
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Soley MB, Markmann A, Batista VS. Classical Optimal Control for Energy Minimization Based On Diffeomorphic Modulation under Observable-Response-Preserving Homotopy. J Chem Theory Comput 2018; 14:3351-3362. [DOI: 10.1021/acs.jctc.8b00124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Micheline B. Soley
- Department of Chemistry, Yale University, P.O.
Box 208107, New Haven, Connecticut 06520-8107, United States
- Energy Sciences Institute, Yale University, P.O.
Box 27394, West Haven, Connecticut 06516-7394, United States
| | - Andreas Markmann
- Department of Chemistry, Yale University, P.O.
Box 208107, New Haven, Connecticut 06520-8107, United States
- Energy Sciences Institute, Yale University, P.O.
Box 27394, West Haven, Connecticut 06516-7394, United States
| | - Victor S. Batista
- Department of Chemistry, Yale University, P.O.
Box 208107, New Haven, Connecticut 06520-8107, United States
- Energy Sciences Institute, Yale University, P.O.
Box 27394, West Haven, Connecticut 06516-7394, United States
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24
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Yu H, Ho TS, Rabitz H. Optimal control of orientation and entanglement for two dipole–dipole coupled quantum planar rotors. Phys Chem Chem Phys 2018; 20:13008-13029. [DOI: 10.1039/c8cp00231b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Optimal control simulations are performed for orientation and entanglement of two dipole–dipole coupled identical quantum rotors.
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Affiliation(s)
- Hongling Yu
- State Key Laboratory of Precision
- East China Normal University
- Shanghai 200062
- China
- Department of Chemistry
| | - Tak-San Ho
- Department of Chemistry
- Princeton University
- Princeton
- USA
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25
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Campos AG, Cabrera R, Rabitz HA, Bondar DI. Analytic Solutions to Coherent Control of the Dirac Equation. PHYSICAL REVIEW LETTERS 2017; 119:173203. [PMID: 29219449 DOI: 10.1103/physrevlett.119.173203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Indexed: 06/07/2023]
Abstract
A simple framework for Dirac spinors is developed that parametrizes admissible quantum dynamics and also analytically constructs electromagnetic fields, obeying Maxwell's equations, which yield a desired evolution. In particular, we show how to achieve dispersionless rotation and translation of wave packets. Additionally, this formalism can handle control interactions beyond electromagnetic. This work reveals unexpected flexibility of the Dirac equation for control applications, which may open new prospects for quantum technologies.
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Affiliation(s)
- Andre G Campos
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Renan Cabrera
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Herschel A Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Denys I Bondar
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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26
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Chen C, Dong D, Qi B, Petersen IR, Rabitz H. Quantum Ensemble Classification: A Sampling-Based Learning Control Approach. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2017; 28:1345-1359. [PMID: 28113872 DOI: 10.1109/tnnls.2016.2540719] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quantum ensemble classification (QEC) has significant applications in discrimination of atoms (or molecules), separation of isotopes, and quantum information extraction. However, quantum mechanics forbids deterministic discrimination among nonorthogonal states. The classification of inhomogeneous quantum ensembles is very challenging, since there exist variations in the parameters characterizing the members within different classes. In this paper, we recast QEC as a supervised quantum learning problem. A systematic classification methodology is presented by using a sampling-based learning control (SLC) approach for quantum discrimination. The classification task is accomplished via simultaneously steering members belonging to different classes to their corresponding target states (e.g., mutually orthogonal states). First, a new discrimination method is proposed for two similar quantum systems. Then, an SLC method is presented for QEC. Numerical results demonstrate the effectiveness of the proposed approach for the binary classification of two-level quantum ensembles and the multiclass classification of multilevel quantum ensembles.
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27
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Russell B, Rabitz H. Common foundations of optimal control across the sciences: evidence of a free lunch. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0210. [PMID: 28115607 PMCID: PMC5311431 DOI: 10.1098/rsta.2016.0210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/20/2016] [Indexed: 05/22/2023]
Abstract
A common goal in the sciences is optimization of an objective function by selecting control variables such that a desired outcome is achieved. This scenario can be expressed in terms of a control landscape of an objective considered as a function of the control variables. At the most basic level, it is known that the vast majority of quantum control landscapes possess no traps, whose presence would hinder reaching the objective. This paper reviews and extends the quantum control landscape assessment, presenting evidence that the same highly favourable landscape features exist in many other domains of science. The implications of this broader evidence are discussed. Specifically, control landscape examples from quantum mechanics, chemistry and evolutionary biology are presented. Despite the obvious differences, commonalities between these areas are highlighted within a unified mathematical framework. This mathematical framework is driven by the wide-ranging experimental evidence on the ease of finding optimal controls (in terms of the required algorithmic search effort beyond the laboratory set-up overhead). The full scope and implications of this observed common control behaviour pose an open question for assessment in further work.This article is part of the themed issue 'Horizons of cybernetical physics'.
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Affiliation(s)
- Benjamin Russell
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, NJ 08540, USA
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28
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Accanto N, de Roque PM, Galvan-Sosa M, Christodoulou S, Moreels I, van Hulst NF. Rapid and robust control of single quantum dots. LIGHT, SCIENCE & APPLICATIONS 2017; 6:e16239. [PMID: 30167237 PMCID: PMC6062170 DOI: 10.1038/lsa.2016.239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/07/2016] [Accepted: 09/26/2016] [Indexed: 06/01/2023]
Abstract
The combination of single particle detection and ultrafast laser pulses is an instrumental method to track dynamics at the femtosecond time scale in single molecules, quantum dots and plasmonic nanoparticles. Optimal control of the extremely short-lived coherences of these individual systems has so far remained elusive, yet its successful implementation would enable arbitrary external manipulation of otherwise inaccessible nanoscale dynamics. In ensemble measurements, such control is often achieved by resorting to a closed-loop optimization strategy, where the spectral phase of a broadband laser field is iteratively optimized. This scheme needs long measurement times and strong signals to converge to the optimal solution. This requirement is in conflict with the nature of single emitters whose signals are weak and unstable. Here we demonstrate an effective closed-loop optimization strategy capable of addressing single quantum dots at room temperature, using as feedback observable the two-photon photoluminescence induced by a phase-controlled broadband femtosecond laser. Crucial to the optimization loop is the use of a deterministic and robust-against-noise search algorithm converging to the theoretically predicted solution in a reduced amount of steps, even when operating at the few-photon level. Full optimization of the single dot luminescence is obtained within ~100 trials, with a typical integration time of 100 ms per trial. These times are faster than the typical photobleaching times in single molecules at room temperature. Our results show the suitability of the novel approach to perform closed-loop optimizations on single molecules, thus extending the available experimental toolbox to the active control of nanoscale coherences.
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Affiliation(s)
- Nicolò Accanto
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Pablo M de Roque
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | | | - Sotirios Christodoulou
- Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Physics, University of Genova, 16146 Genova, Italy
| | - Iwan Moreels
- Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Niek F van Hulst
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA - Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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29
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Robust control of photoassociation of slow O + H collision. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2016.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Tibbetts KM, Feng XJ, Rabitz H. Exploring experimental fitness landscapes for chemical synthesis and property optimization. Phys Chem Chem Phys 2017; 19:4266-4287. [DOI: 10.1039/c6cp06187g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The topology of experimental fitness landscapes for chemical optimization objectives is assessed through svr-based HDMR modeling.
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31
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Liebel M, Kukura P. Lack of evidence for phase-only control of retinal photoisomerization in the strict one-photon limit. Nat Chem 2016; 9:45-49. [DOI: 10.1038/nchem.2598] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 07/19/2016] [Indexed: 12/23/2022]
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32
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Wigley PB, Everitt PJ, van den Hengel A, Bastian JW, Sooriyabandara MA, McDonald GD, Hardman KS, Quinlivan CD, Manju P, Kuhn CCN, Petersen IR, Luiten AN, Hope JJ, Robins NP, Hush MR. Fast machine-learning online optimization of ultra-cold-atom experiments. Sci Rep 2016; 6:25890. [PMID: 27180805 PMCID: PMC4867626 DOI: 10.1038/srep25890] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/21/2016] [Indexed: 12/04/2022] Open
Abstract
We apply an online optimization process based on machine learning to the production of Bose-Einstein condensates (BEC). BEC is typically created with an exponential evaporation ramp that is optimal for ergodic dynamics with two-body s-wave interactions and no other loss rates, but likely sub-optimal for real experiments. Through repeated machine-controlled scientific experimentation and observations our ‘learner’ discovers an optimal evaporation ramp for BEC production. In contrast to previous work, our learner uses a Gaussian process to develop a statistical model of the relationship between the parameters it controls and the quality of the BEC produced. We demonstrate that the Gaussian process machine learner is able to discover a ramp that produces high quality BECs in 10 times fewer iterations than a previously used online optimization technique. Furthermore, we show the internal model developed can be used to determine which parameters are essential in BEC creation and which are unimportant, providing insight into the optimization process of the system.
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Affiliation(s)
- P B Wigley
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - P J Everitt
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - A van den Hengel
- Australian Centre for Visual Technologies, University of Adelaide, Adelaide, 5005, Australia
| | - J W Bastian
- School of Computer Science, University of Adelaide, Adelaide, 5005, Australia
| | - M A Sooriyabandara
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - G D McDonald
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - K S Hardman
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - C D Quinlivan
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - P Manju
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - C C N Kuhn
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - I R Petersen
- School of Engineering and Information Technology, University of New South Wales at the Australian Defence Force Academy, Canberra, 2600, Australia
| | - A N Luiten
- Institute for Photonics &Advanced Sensing, School of Physical Sciences,The University of Adelaide, Adelaide, 5005, Australia
| | - J J Hope
- Department of Quantum Science, Australian National University, Canberra, 2601, Australia
| | - N P Robins
- Quantum Sensors and Atomlaser Lab, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, 2601, Australia
| | - M R Hush
- School of Engineering and Information Technology, University of New South Wales at the Australian Defence Force Academy, Canberra, 2600, Australia
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33
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Photonic reagents for concentration measurement of flu-orescent proteins with overlapping spectra. Sci Rep 2016; 6:25827. [PMID: 27181496 PMCID: PMC4867436 DOI: 10.1038/srep25827] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 04/21/2016] [Indexed: 12/12/2022] Open
Abstract
By exploiting photonic reagents (i.e., coherent control by shaped laser pulses), we employ Optimal Dynamic Discrimination (ODD) as a novel means for quantitatively characterizing mixtures of fluorescent proteins with a large spectral overlap. To illustrate ODD, we simultaneously measured concentrations of in vitro mixtures of Enhanced Blue Fluorescent Protein (EBFP) and Enhanced Cyan Fluorescent Protein (ECFP). Building on this foundational study, the ultimate goal is to exploit the capabilities of ODD for parallel monitoring of genetic and protein circuits by suppressing the spectral cross-talk among multiple fluorescent reporters.
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34
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Sørensen JJWH, Pedersen MK, Munch M, Haikka P, Jensen JH, Planke T, Andreasen MG, Gajdacz M, Mølmer K, Lieberoth A, Sherson JF. Exploring the quantum speed limit with computer games. Nature 2016; 532:210-3. [PMID: 27075097 DOI: 10.1038/nature17620] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 02/12/2016] [Indexed: 12/11/2022]
Abstract
Humans routinely solve problems of immense computational complexity by intuitively forming simple, low-dimensional heuristic strategies. Citizen science (or crowd sourcing) is a way of exploiting this ability by presenting scientific research problems to non-experts. 'Gamification'--the application of game elements in a non-game context--is an effective tool with which to enable citizen scientists to provide solutions to research problems. The citizen science games Foldit, EteRNA and EyeWire have been used successfully to study protein and RNA folding and neuron mapping, but so far gamification has not been applied to problems in quantum physics. Here we report on Quantum Moves, an online platform gamifying optimization problems in quantum physics. We show that human players are able to find solutions to difficult problems associated with the task of quantum computing. Players succeed where purely numerical optimization fails, and analyses of their solutions provide insights into the problem of optimization of a more profound and general nature. Using player strategies, we have thus developed a few-parameter heuristic optimization method that efficiently outperforms the most prominent established numerical methods. The numerical complexity associated with time-optimal solutions increases for shorter process durations. To understand this better, we produced a low-dimensional rendering of the optimization landscape. This rendering reveals why traditional optimization methods fail near the quantum speed limit (that is, the shortest process duration with perfect fidelity). Combined analyses of optimization landscapes and heuristic solution strategies may benefit wider classes of optimization problems in quantum physics and beyond.
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Affiliation(s)
| | | | - Michael Munch
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Pinja Haikka
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Tilo Planke
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Miroslav Gajdacz
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Klaus Mølmer
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Andreas Lieberoth
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Jacob F Sherson
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
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35
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Zhang W, Dong D, Petersen IR, Rabitz HA. Sampling-based robust control in synchronizing collision with shaped laser pulses: an application in charge transfer for H + + D → H + D +. RSC Adv 2016. [DOI: 10.1039/c6ra16158h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this paper, we show that robust laser pulses can be obtained by a sampling-based method to achieve a desired charge transfer probability with limited sensitivity to the arrival time of laser pulses.
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Affiliation(s)
- Wei Zhang
- School of Engineering and Information Technology
- University of New South Wales
- Canberra 2600
- Australia
| | - Daoyi Dong
- School of Engineering and Information Technology
- University of New South Wales
- Canberra 2600
- Australia
| | - Ian R. Petersen
- School of Engineering and Information Technology
- University of New South Wales
- Canberra 2600
- Australia
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36
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Sun Q, Pelczer I, Riviello G, Wu RB, Rabitz H. Identifying and avoiding singularity-induced local traps over control landscapes of spin chain systems. Phys Chem Chem Phys 2015; 17:29714-22. [PMID: 26478216 DOI: 10.1039/c5cp05418d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The wide success of quantum optimal control in experiments and simulations is attributed to the properties of the control landscape, defined by the objective value as a functional of the controls. Prior analysis has shown that on satisfaction of some underlying assumptions, the landscapes are free of suboptimal traps that could halt the search for a global optimum with gradient-based algorithms. However, violation of one particular assumption can give rise to a so-called singular control, possibly bringing about local traps on the corresponding landscapes in some particular situations. This paper theoretically and experimentally demonstrates the existence of singular traps on the landscape in linear spin-1/2 chains with Ising couplings between nearest neighbors and with certain field components set to zero. The results in a two-spin example show how a trap influences the search trajectories passing by it, and how to avoid encountering such traps in practice by choosing sufficiently strong initial control fields. The findings are also discussed in the context of the generally observed success of quantum control.
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Affiliation(s)
- Qiuyang Sun
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
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37
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Chang BY, Shin S, Sola IR. State-Selective Excitation of Quantum Systems via Geometrical Optimization. J Chem Theory Comput 2015; 11:4005-10. [DOI: 10.1021/acs.jctc.5b00522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bo Y. Chang
- School
of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Seokmin Shin
- School
of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Ignacio R. Sola
- Departamento
de Química Física, Universidad Complutense, 28040 Madrid, Spain
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38
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Anderson BE, Sosa-Martinez H, Riofrío CA, Deutsch IH, Jessen PS. Accurate and Robust Unitary Transformations of a High-Dimensional Quantum System. PHYSICAL REVIEW LETTERS 2015. [PMID: 26196968 DOI: 10.1103/physrevlett.114.240401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Unitary transformations are the most general input-output maps available in closed quantum systems. Good control protocols have been developed for qubits, but questions remain about the use of optimal control theory to design unitary maps in high-dimensional Hilbert spaces, and about the feasibility of their robust implementation in the laboratory. Here we design and implement unitary maps in a 16-dimensional Hilbert space associated with the 6S(1/2) ground state of (133)Cs, achieving fidelities >0.98 with built-in robustness to static and dynamic perturbations. Our work has relevance for quantum information processing and provides a template for similar advances on other physical platforms.
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Affiliation(s)
- B E Anderson
- Center for Quantum Information and Control, College of Optical Sciences and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
- National Institute of Standards and Technology and Joint Quantum Institute, NIST and the University of Maryland, Gaithersburg, Maryland 20899, USA
| | - H Sosa-Martinez
- Center for Quantum Information and Control, College of Optical Sciences and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - C A Riofrío
- Center for Quantum Information and Control, Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA
- Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ivan H Deutsch
- Center for Quantum Information and Control, Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Poul S Jessen
- Center for Quantum Information and Control, College of Optical Sciences and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
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39
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Joe-Wong C, Ho TS, Rabitz H, Wu R. Topology of classical molecular optimal control landscapes for multi-target objectives. J Chem Phys 2015; 142:154115. [PMID: 25903874 DOI: 10.1063/1.4918274] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
This paper considers laser-driven optimal control of an ensemble of non-interacting molecules whose dynamics lie in classical phase space. The molecules evolve independently under control to distinct final states. We consider a control landscape defined in terms of multi-target (MT) molecular states and analyze the landscape as a functional of the control field. The topology of the MT control landscape is assessed through its gradient and Hessian with respect to the control. Under particular assumptions, the MT control landscape is found to be free of traps that could hinder reaching the objective. The Hessian associated with an optimal control field is shown to have finite rank, indicating an inherent degree of robustness to control noise. Both the absence of traps and rank of the Hessian are shown to be analogous to the situation of specifying multiple targets for an ensemble of quantum states. Numerical simulations are presented to illustrate the classical landscape principles and further characterize the system behavior as the control field is optimized.
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Affiliation(s)
- Carlee Joe-Wong
- Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544-1000, USA
| | - Tak-San Ho
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009, USA
| | - Rebing Wu
- Department of Automation, Tsinghua University, Beijing, People's Republic of China
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40
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Soley M, Markmann A, Batista VS. Steered quantum dynamics for energy minimization. J Phys Chem B 2015; 119:715-27. [PMID: 25122515 DOI: 10.1021/jp5046723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We introduce a quantum optimal control algorithm for energy minimization that combines the diffeomorphic modulation under observable response preserving homotopy (D-MORPH) gradient and the Broyden Fletcher Goldfarb Shanno (BFGS) iterative scheme for nonlinear optimization. An extended set of controls defining the time-dependent mass, dipole moment, and external perturbational field are optimized to find an effective Hamiltonian that steers the dynamics of the system into the global minimum without getting trapped into local minima. The algorithm is illustrated as applied to energy minimization on rugged surfaces and golf potentials comparable to those previously explored for testing quantum annealing methodologies.
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Affiliation(s)
- Micheline Soley
- Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
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41
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Dong D, Chen C, Qi B, Petersen IR, Nori F. Robust manipulation of superconducting qubits in the presence of fluctuations. Sci Rep 2015; 5:7873. [PMID: 25598529 PMCID: PMC4297962 DOI: 10.1038/srep07873] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/12/2014] [Indexed: 11/09/2022] Open
Abstract
Superconducting quantum systems are promising candidates for quantum information processing due to their scalability and design flexibility. However, the existence of defects, fluctuations, and inaccuracies is unavoidable for practical superconducting quantum circuits. In this paper, a sampling-based learning control (SLC) method is used to guide the design of control fields for manipulating superconducting quantum systems. Numerical results for one-qubit systems and coupled two-qubit systems show that the "smart" fields learned using the SLC method can achieve robust manipulation of superconducting qubits, even in the presence of large fluctuations and inaccuracies.
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Affiliation(s)
- Daoyi Dong
- School of Engineering and Information Technology, University of New South Wales, Canberra 2600, Australia
| | - Chunlin Chen
- Department of Control and System Engineering, School of Management and Engineering, Nanjing University, Nanjing 210093, China
| | - Bo Qi
- Key Laboratory of Systems and Control, ISS, and National Center for Mathematics and Interdis-ciplinary Sciences, Academy of Mathematics and Systems Science, CAS, Beijing 100190, China
| | - Ian R Petersen
- School of Engineering and Information Technology, University of New South Wales, Canberra 2600, Australia
| | - Franco Nori
- 1] CEMS, RIKEN, Saitama351-0198, Japan [2] Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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42
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Nanduri A, Shir OM, Donovan A, Ho TS, Rabitz H. Exploring the complexity of quantum control optimization trajectories. Phys Chem Chem Phys 2015; 17:334-47. [PMID: 25377547 DOI: 10.1039/c4cp03853c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The control of quantum system dynamics is generally performed by seeking a suitable applied field. The physical objective as a functional of the field forms the quantum control landscape, whose topology, under certain conditions, has been shown to contain no critical point suboptimal traps, thereby enabling effective searches for fields that give the global maximum of the objective. This paper addresses the structure of the landscape as a complement to topological critical point features. Recent work showed that landscape structure is highly favorable for optimization of state-to-state transition probabilities, in that gradient-based control trajectories to the global maximum value are nearly straight paths. The landscape structure is codified in the metric R ≥ 1.0, defined as the ratio of the length of the control trajectory to the Euclidean distance between the initial and optimal controls. A value of R = 1 would indicate an exactly straight trajectory to the optimal observable value. This paper extends the state-to-state transition probability results to the quantum ensemble and unitary transformation control landscapes. Again, nearly straight trajectories predominate, and we demonstrate that R can take values approaching 1.0 with high precision. However, the interplay of optimization trajectories with critical saddle submanifolds is found to influence landscape structure. A fundamental relationship necessary for perfectly straight gradient-based control trajectories is derived, wherein the gradient on the quantum control landscape must be an eigenfunction of the Hessian. This relation is an indicator of landscape structure and may provide a means to identify physical conditions when control trajectories can achieve perfect linearity. The collective favorable landscape topology and structure provide a foundation to understand why optimal quantum control can be readily achieved.
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Affiliation(s)
- Arun Nanduri
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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43
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Moore Tibbetts K, Rabitz H. Constrained control landscape for population transfer in a two-level system. Phys Chem Chem Phys 2015; 17:3164-78. [DOI: 10.1039/c4cp04792c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlling population transfer in a two-level quantum system reveals a landscape with a rich structure containing highly connected optimal regions.
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44
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Abstract
The identification of quantum system Hamiltonians through the use of experimental data remains an important research goal. Seeking a Hamiltonian that is consistent with experimental measurements constitutes an excursion over a Hamiltonian inversion landscape, which is the quality of reproducing the data as a function of the Hamiltonian parameters. Recent theoretical work showed that with sufficient experimental data there should be local convexity about the true Hamiltonian on the landscape. The present paper builds on this result and performs simulations to test whether such convexity is observed. A gradient-based Hamiltonian search algorithm is incorporated into an inversion routine as a means to explore the local inversion landscape. The simulations consider idealized noise-free as well as noise-ridden experimental data. The results suggest that a sizable convex domain exists about the true Hamiltonian, even with a modest amount of experimental data and in the presence of a reasonable level of noise.
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Affiliation(s)
- Ashley Donovan
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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45
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Shir OM, Roslund J, Whitley D, Rabitz H. Efficient retrieval of landscape Hessian: forced optimal covariance adaptive learning. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:063306. [PMID: 25019911 DOI: 10.1103/physreve.89.063306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Indexed: 06/03/2023]
Abstract
Knowledge of the Hessian matrix at the landscape optimum of a controlled physical observable offers valuable information about the system robustness to control noise. The Hessian can also assist in physical landscape characterization, which is of particular interest in quantum system control experiments. The recently developed landscape theoretical analysis motivated the compilation of an automated method to learn the Hessian matrix about the global optimum without derivative measurements from noisy data. The current study introduces the forced optimal covariance adaptive learning (FOCAL) technique for this purpose. FOCAL relies on the covariance matrix adaptation evolution strategy (CMA-ES) that exploits covariance information amongst the control variables by means of principal component analysis. The FOCAL technique is designed to operate with experimental optimization, generally involving continuous high-dimensional search landscapes (≳30) with large Hessian condition numbers (≳10^{4}). This paper introduces the theoretical foundations of the inverse relationship between the covariance learned by the evolution strategy and the actual Hessian matrix of the landscape. FOCAL is presented and demonstrated to retrieve the Hessian matrix with high fidelity on both model landscapes and quantum control experiments, which are observed to possess nonseparable, nonquadratic search landscapes. The recovered Hessian forms were corroborated by physical knowledge of the systems. The implications of FOCAL extend beyond the investigated studies to potentially cover other physically motivated multivariate landscapes.
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Affiliation(s)
- Ofer M Shir
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Jonathan Roslund
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Darrell Whitley
- Department of Computer Science, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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46
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Chen C, Dong D, Li HX, Chu J, Tarn TJ. Fidelity-based probabilistic Q-learning for control of quantum systems. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2014; 25:920-933. [PMID: 24808038 DOI: 10.1109/tnnls.2013.2283574] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The balance between exploration and exploitation is a key problem for reinforcement learning methods, especially for Q-learning. In this paper, a fidelity-based probabilistic Q-learning (FPQL) approach is presented to naturally solve this problem and applied for learning control of quantum systems. In this approach, fidelity is adopted to help direct the learning process and the probability of each action to be selected at a certain state is updated iteratively along with the learning process, which leads to a natural exploration strategy instead of a pointed one with configured parameters. A probabilistic Q-learning (PQL) algorithm is first presented to demonstrate the basic idea of probabilistic action selection. Then the FPQL algorithm is presented for learning control of quantum systems. Two examples (a spin-1/2 system and a Λ-type atomic system) are demonstrated to test the performance of the FPQL algorithm. The results show that FPQL algorithms attain a better balance between exploration and exploitation, and can also avoid local optimal policies and accelerate the learning process.
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47
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Roslund J, Rabitz H. Dynamic dimensionality identification for quantum control. PHYSICAL REVIEW LETTERS 2014; 112:143001. [PMID: 24765949 DOI: 10.1103/physrevlett.112.143001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Indexed: 06/03/2023]
Abstract
The control of quantum systems with shaped laser pulses presents a paradox since the relative ease with which solutions are discovered appears incompatible with the enormous variety of pulse shapes accessible with a standard pulse shaper. Quantum landscape theory indicates that the relevant search dimensionality is not dictated by the number of pulse shaper elements, but rather is related to the number of states participating in the controlled dynamics. The actual dimensionality is encoded within the sensitivity of the observed yield to all of the pulse shaper elements. To investigate this proposition, the Hessian matrix is measured for controlled transitions amongst states of atomic rubidium, and its eigendecomposition reveals a dimensionality consistent with that predicted by landscape theory. Additionally, this methodology furnishes a low-dimensional picture that captures the essence of the light-matter interaction and the ensuing system dynamics.
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Affiliation(s)
- Jonathan Roslund
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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48
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Zhang W, Shu CC, Ho TS, Rabitz H, Cong SL. Optimal control of charge transfer for slow H+ + D collisions with shaped laser pulses. J Chem Phys 2014; 140:094304. [PMID: 24606358 DOI: 10.1063/1.4867057] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We show that optimally shaped laser pulses can beneficially influence charge transfer in slow H(+)+D collisions. Time-dependent wave packet optimal control simulations are performed based on a two-state adiabatic Hamiltonian. Optimal control is performed using either an adaptive or a fixed target to obtain the desired laser control field. In the adaptive target scheme, the target state is updated according to the renormalized fragmentary yield in the exit channel throughout the optimization process. In the fixed target scheme, the target state in the exit channel is a normalized outgoing Gaussian wave packet located at a large internuclear separation. Both approaches produced excellent optimal outcomes, far exceeding that achieved in the field-free collisional charge transfer. The adaptive target scheme proves to be more efficient, and often with complex final wave packet. In contrast, the fixed target scheme, although more slowly convergent, is found to produce high fidelity for the desired target wave packet. The control mechanism in both cases utilizes bound vibrational states of the transient HD(+) complex.
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Affiliation(s)
- Wei Zhang
- School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
| | - Chuan-Cun Shu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Tak-San Ho
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Shu-Lin Cong
- School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China
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49
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Moore Tibbetts K, Xing X, Rabitz H. Laboratory transferability of optimally shaped laser pulses for quantum control. J Chem Phys 2014; 140:074302. [PMID: 24559348 DOI: 10.1063/1.4863137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Optimal control experiments can readily identify effective shaped laser pulses, or "photonic reagents," that achieve a wide variety of objectives. An important additional practical desire is for photonic reagent prescriptions to produce good, if not optimal, objective yields when transferred to a different system or laboratory. Building on general experience in chemistry, the hope is that transferred photonic reagent prescriptions may remain functional even though all features of a shaped pulse profile at the sample typically cannot be reproduced exactly. As a specific example, we assess the potential for transferring optimal photonic reagents for the objective of optimizing a ratio of photoproduct ions from a family of halomethanes through three related experiments. First, applying the same set of photonic reagents with systematically varying second- and third-order chirp on both laser systems generated similar shapes of the associated control landscape (i.e., relation between the objective yield and the variables describing the photonic reagents). Second, optimal photonic reagents obtained from the first laser system were found to still produce near optimal yields on the second laser system. Third, transferring a collection of photonic reagents optimized on the first laser system to the second laser system reproduced systematic trends in photoproduct yields upon interaction with the homologous chemical family. These three transfers of photonic reagents are demonstrated to be successful upon paying reasonable attention to overall laser system characteristics. The ability to transfer photonic reagents from one laser system to another is analogous to well-established utilitarian operating procedures with traditional chemical reagents. The practical implications of the present results for experimental quantum control are discussed.
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Affiliation(s)
| | - Xi Xing
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Herschel Rabitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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50
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Abstract
We consider manipulation of the transmission coefficient for a quantum particle moving in one dimension where the shape of the potential is taken as the control. We show that the control landscape, the transmission as a functional of the potential, has no traps, i.e., any maxima correspond to full transmission.
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Affiliation(s)
- Alexander N. Pechen
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
- Steklov Mathematical Institute of Russian Academy of Sciences, Gubkina str. 8, Moscow 119991, Russia
| | - David J. Tannor
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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