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Hamilton JR, Amarotti E, Dibenedetto CN, Striccoli M, Levine RD, Collini E, Remacle F. Time-Frequency Signatures of Electronic Coherence of Colloidal CdSe Quantum Dot Dimer Assemblies Probed at Room Temperature by Two-Dimensional Electronic Spectroscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2096. [PMID: 37513107 PMCID: PMC10384478 DOI: 10.3390/nano13142096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
Electronic coherence signatures can be directly identified in the time-frequency maps measured in two-dimensional electronic spectroscopy (2DES). Here, we demonstrate the theory and discuss the advantages of this approach via the detailed application to the fast-femtosecond beatings of a wide variety of electronic coherences in ensemble dimers of quantum dots (QDs), assembled from QDs of 3 nm in diameter, with 8% size dispersion in diameter. The observed and computed results can be consistently characterized directly in the time-frequency domain by probing the polarization in the 2DES setup. The experimental and computed time-frequency maps are found in very good agreement, and several electronic coherences are characterized at room temperature in solution, before the extensive dephasing due to the size dispersion begins. As compared to the frequency-frequency maps that are commonly used in 2DES, the time-frequency maps allow exploiting electronic coherences without additional post-processing and with fewer 2DES measurements. Towards quantum technology applications, we also report on the modeling of the time-frequency photocurrent response of these electronic coherences, which paves the way to integrating QD devices with classical architectures, thereby enhancing the quantum advantage of such technologies for parallel information processing at room temperature.
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Affiliation(s)
- James R Hamilton
- Department of Theoretical Physical Chemistry, University of Liège, B4000 Liège, Belgium
| | - Edoardo Amarotti
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Carlo N Dibenedetto
- CNR-IPCF SS Bari, c/o Chemistry Department, University of Bari Aldo Moro, 70126 Bari, Italy
- Chemistry Department, University of Bari Aldo Moro, 70126 Bari, Italy
| | - Marinella Striccoli
- CNR-IPCF SS Bari, c/o Chemistry Department, University of Bari Aldo Moro, 70126 Bari, Italy
| | - Raphael D Levine
- The Fritz Haber Research Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Francoise Remacle
- Department of Theoretical Physical Chemistry, University of Liège, B4000 Liège, Belgium
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Remacle F, Levine RD. A quantum information processing machine for computing by observables. Proc Natl Acad Sci U S A 2023; 120:e2220069120. [PMID: 36897984 PMCID: PMC10243124 DOI: 10.1073/pnas.2220069120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/31/2023] [Indexed: 03/12/2023] Open
Abstract
A quantum machine that accepts an input and processes it in parallel is described. The logic variables of the machine are not wavefunctions (qubits) but observables (i.e., operators) and its operation is described in the Heisenberg picture. The active core is a solid-state assembly of small nanosized colloidal quantum dots (QDs) or dimers of dots. The size dispersion of the QDs that causes fluctuations in their discrete electronic energies is a limiting factor. The input to the machine is provided by a train of very brief laser pulses, at least four in number. The coherent band width of each ultrashort pulse needs to span at least several and preferably all the single electron excited states of the dots. The spectrum of the QD assembly is measured as a function of the time delays between the input laser pulses. The dependence of the spectrum on the time delays can be Fourier transformed to a frequency spectrum. This spectrum of a finite range in time is made up of discrete pixels. These are the visible, raw, basic logic variables. The spectrum is analyzed to determine a possibly smaller number of principal components. A Lie-algebraic point of view is used to explore the use of the machine to emulate the dynamics of other quantum systems. An explicit example demonstrates the considerable quantum advantage of our scheme.
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Affiliation(s)
- F. Remacle
- Theoretical Physical Chemistry, University of Liège, 4000Liège, Belgium
- The Fritz Haber Research Center for Molecular Dynamics, The Hebrew University of Jerusalem, 91904Jerusalem, Israel
| | - R. D. Levine
- The Fritz Haber Research Center for Molecular Dynamics, The Hebrew University of Jerusalem, 91904Jerusalem, Israel
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California, Los Angeles, CA90095
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA90095
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Gupta R, Levine RD, Kais S. Convergence of a Reconstructed Density Matrix to a Pure State Using the Maximal Entropy Approach. J Phys Chem A 2021; 125:7588-7595. [PMID: 34410718 DOI: 10.1021/acs.jpca.1c05884] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Impressive progress has been made in the past decade in the study of technological applications of varied types of quantum systems. With industry giants like IBM laying down their roadmap for scalable quantum devices with more than 1000-qubits by the end of 2023, efficient validation techniques are also being developed for testing quantum processing on these devices. The characterization of a quantum state is done by experimental measurements through the process called quantum state tomography (QST) which scales exponentially with the size of the system. However, QST performed using incomplete measurements is aptly suited for characterizing these quantum technologies especially with the current nature of noisy intermediate-scale quantum (NISQ) devices where not all mean measurements are available with high fidelity. We, hereby, propose an alternative approach to QST for the complete reconstruction of the density matrix of a quantum system in a pure state for any number of qubits by applying the maximal entropy formalism on the pairwise combinations of the known mean measurements. This approach provides the best estimate of the target state when we know the complete set of observables, which is the case of convergence of the reconstructed density matrix to a pure state. Our goal is to provide a practical inference of a quantum system in a pure state that can find its applications in the field of quantum error mitigation on a real quantum computer that we intend to investigate further.
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Affiliation(s)
- Rishabh Gupta
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Raphael D Levine
- The Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.,Department of Chemistry and Biochemistry and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, United States
| | - Sabre Kais
- Department of Chemistry, Department of Physics and Astronomy, and Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
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Gyongyosi L, Imre S. Scalable distributed gate-model quantum computers. Sci Rep 2021; 11:5172. [PMID: 33637770 PMCID: PMC7910494 DOI: 10.1038/s41598-020-76728-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/30/2020] [Indexed: 11/08/2022] Open
Abstract
A scalable model for a distributed quantum computation is a challenging problem due to the complexity of the problem space provided by the diversity of possible quantum systems, from small-scale quantum devices to large-scale quantum computers. Here, we define a model of scalable distributed gate-model quantum computation in near-term quantum systems of the NISQ (noisy intermediate scale quantum) technology era. We prove that the proposed architecture can maximize an objective function of a computational problem in a distributed manner. We study the impacts of decoherence on distributed objective function evaluation.
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Affiliation(s)
- Laszlo Gyongyosi
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, 1117, Hungary.
- MTA-BME Information Systems Research Group, Hungarian Academy of Sciences, Budapest, 1051, Hungary.
| | - Sandor Imre
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, 1117, Hungary
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Collini E, Gattuso H, Levine RD, Remacle F. Ultrafast fs coherent excitonic dynamics in CdSe quantum dots assemblies addressed and probed by 2D electronic spectroscopy. J Chem Phys 2021; 154:014301. [DOI: 10.1063/5.0031420] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Hugo Gattuso
- Theoretical Physical Chemistry, RU MOLSYS, University of Liège, Allée du 6 Août 11, B4000 Liège, Belgium
| | - R. D. Levine
- The Fritz Haber Research Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - F. Remacle
- Theoretical Physical Chemistry, RU MOLSYS, University of Liège, Allée du 6 Août 11, B4000 Liège, Belgium
- The Fritz Haber Research Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Gyongyosi L, Imre S. Resource prioritization and balancing for the quantum internet. Sci Rep 2020; 10:22390. [PMID: 33372180 PMCID: PMC7770047 DOI: 10.1038/s41598-020-78960-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/02/2020] [Indexed: 11/21/2022] Open
Abstract
The quantum Internet enables networking based on the fundamentals of quantum mechanics. Here, methods and procedures of resource prioritization and resource balancing are defined for the quantum Internet. We define a model for resource consumption optimization in quantum repeaters, and a strongly-entangled network structure for resource balancing. We study the resource-balancing efficiency of the strongly-entangled structure. We prove that a strongly-entangled quantum network is two times more efficient in a resource balancing problem than a full-mesh network of the traditional Internet.
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Affiliation(s)
- Laszlo Gyongyosi
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, 1117, Hungary.
- MTA-BME Information Systems Research Group, Hungarian Academy of Sciences, Budapest, 1051, Hungary.
| | - Sandor Imre
- Department of Networked Systems and Services, Budapest University of Technology and Economics, Budapest, 1117, Hungary
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