1
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Eriksson AM, Sépulcre T, Kervinen M, Hillmann T, Kudra M, Dupouy S, Lu Y, Khanahmadi M, Yang J, Castillo-Moreno C, Delsing P, Gasparinetti S. Universal control of a bosonic mode via drive-activated native cubic interactions. Nat Commun 2024; 15:2512. [PMID: 38509084 PMCID: PMC10954688 DOI: 10.1038/s41467-024-46507-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Linear bosonic modes offer a hardware-efficient alternative for quantum information processing but require access to some nonlinearity for universal control. The lack of nonlinearity in photonics has led to encoded measurement-based quantum computing, which relies on linear operations but requires access to resourceful ('nonlinear') quantum states, such as cubic phase states. In contrast, superconducting microwave circuits offer engineerable nonlinearities but suffer from static Kerr nonlinearity. Here, we demonstrate universal control of a bosonic mode composed of a superconducting nonlinear asymmetric inductive element (SNAIL) resonator, enabled by native nonlinearities in the SNAIL element. We suppress static nonlinearities by operating the SNAIL in the vicinity of its Kerr-free point and dynamically activate nonlinearities up to third order by fast flux pulses. We experimentally realize a universal set of generalized squeezing operations, as well as the cubic phase gate, and exploit them to deterministically prepare a cubic phase state in 60 ns. Our results initiate the experimental field of polynomial quantum computing, in the continuous-variables notion originally introduced by Lloyd and Braunstein.
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Affiliation(s)
- Axel M Eriksson
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
| | - Théo Sépulcre
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Mikael Kervinen
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Timo Hillmann
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Marina Kudra
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Simon Dupouy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Yong Lu
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
- Physikalisches Institut, University of Stuttgart, 70569, Stuttgart, Germany
| | - Maryam Khanahmadi
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Jiaying Yang
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Claudia Castillo-Moreno
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Per Delsing
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
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2
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Tholén MO, Borgani R, Di Carlo GR, Bengtsson A, Križan C, Kudra M, Tancredi G, Bylander J, Delsing P, Gasparinetti S, Haviland DB. Measurement and control of a superconducting quantum processor with a fully integrated radio-frequency system on a chip. Rev Sci Instrum 2022; 93:104711. [PMID: 36319392 DOI: 10.1063/5.0101398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
We describe a digital microwave platform called Presto, designed for measurement and control of multiple quantum bits (qubits) and based on the third-generation radio-frequency system on a chip. Presto uses direct digital synthesis to create signals up to 9 GHz on 16 synchronous output ports, while synchronously analyzing responses on 16 input ports. Presto has 16 DC-bias outputs, four inputs and four outputs for digital triggers or markers, and two continuous-wave outputs for synthesizing frequencies up to 15 GHz. Scaling to a large number of qubits is enabled through deterministic synchronization of multiple Presto units. A Python application programming interface configures a firmware for synthesis and analysis of pulses, coordinated by an event sequencer. The analysis integrates template matching (matched filtering) and low-latency (184-254 ns) feedback to enable a wide range of multi-qubit experiments. We demonstrate Presto's capabilities with experiments on a sample consisting of two superconducting qubits connected via a flux-tunable coupler. We show single-shot readout and active reset of a single qubit; randomized benchmarking of single-qubit gates showing 99.972% fidelity, limited by the coherence time of the qubit; and calibration of a two-qubit iSWAP gate.
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Affiliation(s)
- Mats O Tholén
- Nanostructure Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - Riccardo Borgani
- Nanostructure Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden
| | | | - Andreas Bengtsson
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Christian Križan
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Marina Kudra
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Giovanna Tancredi
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Jonas Bylander
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Per Delsing
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - David B Haviland
- Nanostructure Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden
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3
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Aamir MA, Moreno CC, Sundelin S, Biznárová J, Scigliuzzo M, Patel KE, Osman A, Lozano DP, Strandberg I, Gasparinetti S. Engineering Symmetry-Selective Couplings of a Superconducting Artificial Molecule to Microwave Waveguides. Phys Rev Lett 2022; 129:123604. [PMID: 36179204 DOI: 10.1103/physrevlett.129.123604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 08/08/2022] [Indexed: 06/16/2023]
Abstract
Tailoring the decay rate of structured quantum emitters into their environment opens new avenues for nonlinear quantum optics, collective phenomena, and quantum communications. Here, we demonstrate a novel coupling scheme between an artificial molecule comprising two identical, strongly coupled transmon qubits and two microwave waveguides. In our scheme, the coupling is engineered so that transitions between states of the same (opposite) symmetry, with respect to the permutation operator, are predominantly coupled to one (the other) waveguide. The symmetry-based coupling selectivity, as quantified by the ratio of the coupling strengths, exceeds a factor of 30 for both waveguides in our device. In addition, we implement a Raman process activated by simultaneously driving both waveguides, and show that it can be used to coherently couple states of different symmetry in the single-excitation manifold of the molecule. Using that process, we implement frequency conversion across the waveguides, mediated by the molecule, with efficiency of about 95%. Finally, we show that this coupling arrangement makes it possible to straightforwardly generate spatially separated Bell states propagating across the waveguides. We envisage further applications to quantum thermodynamics, microwave photodetection, and photon-photon gates.
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Affiliation(s)
- Mohammed Ali Aamir
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Claudia Castillo Moreno
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Simon Sundelin
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Janka Biznárová
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Marco Scigliuzzo
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Kowshik Erappaji Patel
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Amr Osman
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - D P Lozano
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Ingrid Strandberg
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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4
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Lu Y, Strandberg I, Quijandría F, Johansson G, Gasparinetti S, Delsing P. Propagating Wigner-Negative States Generated from the Steady-State Emission of a Superconducting Qubit. Phys Rev Lett 2021; 126:253602. [PMID: 34241509 DOI: 10.1103/physrevlett.126.253602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
We experimentally demonstrate the steady-state generation of propagating Wigner-negative states from a continuously driven superconducting qubit. We reconstruct the Wigner function of the radiation emitted into propagating modes defined by their temporal envelopes, using digital filtering. For an optimized temporal filter, we observe a large Wigner logarithmic negativity, in excess of 0.08, in agreement with theory. The fidelity between the theoretical predictions and the states generated experimentally is up to 99%, reaching state-of-the-art realizations in the microwave frequency domain. Our results provide a new way to generate and control nonclassical states, and may enable promising applications such as quantum networks and quantum computation based on waveguide quantum electrodynamics.
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Affiliation(s)
- Yong Lu
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Ingrid Strandberg
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Fernando Quijandría
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Per Delsing
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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5
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Hillmann T, Quijandría F, Johansson G, Ferraro A, Gasparinetti S, Ferrini G. Universal Gate Set for Continuous-Variable Quantum Computation with Microwave Circuits. Phys Rev Lett 2020; 125:160501. [PMID: 33124848 DOI: 10.1103/physrevlett.125.160501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
We provide an explicit construction of a universal gate set for continuous-variable quantum computation with microwave circuits. Such a universal set has been first proposed in quantum-optical setups, but its experimental implementation has remained elusive in that domain due to the difficulties in engineering strong nonlinearities. Here, we show that a realistic three-wave mixing microwave architecture based on the superconducting nonlinear asymmetric inductive element [Frattini et al., Appl. Phys. Lett. 110, 222603 (2017)APPLAB0003-695110.1063/1.4984142] allows us to overcome this difficulty. As an application, we show that this architecture allows for the generation of a cubic phase state with an experimentally feasible procedure. This work highlights a practical advantage of microwave circuits with respect to optical systems for the purpose of engineering non-Gaussian states and opens the quest for continuous-variable algorithms based on few repetitions of elementary gates from the continuous-variable universal set.
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Affiliation(s)
- Timo Hillmann
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
- Institut für Theorie der Statistischen Physik, RWTH Aachen, 52056 Aachen, Germany
| | - Fernando Quijandría
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Alessandro Ferraro
- Centre for Theoretical Atomic, Molecular and Optical Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Simone Gasparinetti
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Giulia Ferrini
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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6
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Scarlino P, van Woerkom DJ, Stockklauser A, Koski JV, Collodo MC, Gasparinetti S, Reichl C, Wegscheider W, Ihn T, Ensslin K, Wallraff A. All-Microwave Control and Dispersive Readout of Gate-Defined Quantum Dot Qubits in Circuit Quantum Electrodynamics. Phys Rev Lett 2019; 122:206802. [PMID: 31172788 DOI: 10.1103/physrevlett.122.206802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/31/2019] [Indexed: 05/27/2023]
Abstract
Developing fast and accurate control and readout techniques is an important challenge in quantum information processing with semiconductor qubits. Here, we study the dynamics and the coherence properties of a GaAs/AlGaAs double quantum dot charge qubit strongly coupled to a frequency-tunable high-impedance resonator. We drive qubit transitions with synthesized microwave pulses and perform qubit readout through the state-dependent frequency shift imparted by the qubit on the dispersively coupled resonator. We perform Rabi oscillation, Ramsey fringe, energy relaxation, and Hahn-echo measurements and find significantly reduced decoherence rates down to γ_{2}/2π∼3 MHz corresponding to coherence times of up to T_{2}∼50 ns for charge states in gate-defined quantum dot qubits. We realize Rabi π pulses of width down to σ∼0.25 ns.
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Affiliation(s)
- P Scarlino
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - D J van Woerkom
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - A Stockklauser
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - J V Koski
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M C Collodo
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - S Gasparinetti
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Reichl
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - W Wegscheider
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Ensslin
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - A Wallraff
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
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7
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Collodo MC, Potočnik A, Gasparinetti S, Besse JC, Pechal M, Sameti M, Hartmann MJ, Wallraff A, Eichler C. Observation of the Crossover from Photon Ordering to Delocalization in Tunably Coupled Resonators. Phys Rev Lett 2019; 122:183601. [PMID: 31144878 DOI: 10.1103/physrevlett.122.183601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Networks of nonlinear resonators offer intriguing perspectives as quantum simulators for nonequilibrium many-body phases of driven-dissipative systems. Here, we employ photon correlation measurements to study the radiation fields emitted from a system of two superconducting resonators in a driven-dissipative regime, coupled nonlinearly by a superconducting quantum interference device, with cross-Kerr interactions dominating over on-site Kerr interactions. We apply a parametrically modulated magnetic flux to control the linear photon hopping rate between the two resonators and its ratio with the cross-Kerr rate. When increasing the hopping rate, we observe a crossover from an ordered to a delocalized state of photons. The presented coupling scheme is intrinsically robust to frequency disorder and may therefore prove useful for realizing larger-scale resonator arrays.
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Affiliation(s)
| | - Anton Potočnik
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | | | - Marek Pechal
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Mahdi Sameti
- Institute of Photonics and Quantum Sciences, Heriot-Watt University Edinburgh EH14 4AS, United Kingdom
| | - Michael J Hartmann
- Institute of Photonics and Quantum Sciences, Heriot-Watt University Edinburgh EH14 4AS, United Kingdom
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8
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Magnard P, Kurpiers P, Royer B, Walter T, Besse JC, Gasparinetti S, Pechal M, Heinsoo J, Storz S, Blais A, Wallraff A. Fast and Unconditional All-Microwave Reset of a Superconducting Qubit. Phys Rev Lett 2018; 121:060502. [PMID: 30141638 DOI: 10.1103/physrevlett.121.060502] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Active qubit reset is a key operation in many quantum algorithms, and particularly in quantum error correction. Here, we experimentally demonstrate a reset scheme for a three-level transmon artificial atom coupled to a large bandwidth resonator. The reset protocol uses a microwave-induced interaction between the |f,0⟩ and |g,1⟩ states of the coupled transmon-resonator system, with |g⟩ and |f⟩ denoting the ground and second excited states of the transmon, and |0⟩ and |1⟩ the photon Fock states of the resonator. We characterize the reset process and demonstrate reinitialization of the transmon-resonator system to its ground state in less than 500 ns and with 0.2% residual excitation. Our protocol is of practical interest as it has no additional architectural requirements beyond those needed for fast and efficient single-shot readout of transmons, and does not require feedback.
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Affiliation(s)
- P Magnard
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - P Kurpiers
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - B Royer
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - T Walter
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J-C Besse
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Gasparinetti
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Pechal
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Heinsoo
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Storz
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Blais
- Institut Quantique and Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
- Canadian Institute for Advanced Research, Toronto, Ontario M5G IZ8, Canada
| | - A Wallraff
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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9
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Gasparinetti S, Pechal M, Besse JC, Mondal M, Eichler C, Wallraff A. Correlations and Entanglement of Microwave Photons Emitted in a Cascade Decay. Phys Rev Lett 2017; 119:140504. [PMID: 29053288 DOI: 10.1103/physrevlett.119.140504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Indexed: 06/07/2023]
Abstract
We use a three-level artificial atom in the ladder configuration as a source of correlated, single microwave photons of different frequency. The artificial atom, a transmon-type superconducting circuit, is driven at the two-photon transition between ground and second-excited state, and embedded into an on-chip switch that selectively routes different-frequency photons into different spatial modes. Under continuous driving, we measure power cross-correlations between the two modes and observe a crossover between strong antibunching and superbunching, typical of cascade decay, and an oscillatory pattern as the drive strength becomes comparable to the radiative decay rate. By preparing the source in a superposition state using an excitation pulse, we achieve deterministic generation of entangled photon pairs, as demonstrated by nonvanishing phase correlations and more generally by joint quantum state tomography of the two itinerant photonic modes.
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Affiliation(s)
| | - Marek Pechal
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | - Mintu Mondal
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
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10
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Gasparinetti S, Berger S, Abdumalikov AA, Pechal M, Filipp S, Wallraff AJ. Measurement of a vacuum-induced geometric phase. Sci Adv 2016; 2:e1501732. [PMID: 27386533 PMCID: PMC4928991 DOI: 10.1126/sciadv.1501732] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/11/2016] [Indexed: 06/01/2023]
Abstract
Berry's geometric phase naturally appears when a quantum system is driven by an external field whose parameters are slowly and cyclically changed. A variation in the coupling between the system and the external field can also give rise to a geometric phase, even when the field is in the vacuum state or any other Fock state. We demonstrate the appearance of a vacuum-induced Berry phase in an artificial atom, a superconducting transmon, interacting with a single mode of a microwave cavity. As we vary the phase of the interaction, the artificial atom acquires a geometric phase determined by the path traced out in the combined Hilbert space of the atom and the quantum field. Our ability to control this phase opens new possibilities for the geometric manipulation of atom-cavity systems also in the context of quantum information processing.
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Affiliation(s)
| | - Simon Berger
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | | | - Marek Pechal
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Stefan Filipp
- IBM Thomas J. Watson Research Center, Yorktown Heights, NY 10598, USA
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11
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Solinas P, Gasparinetti S. Full distribution of work done on a quantum system for arbitrary initial states. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 92:042150. [PMID: 26565211 DOI: 10.1103/physreve.92.042150] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Indexed: 06/05/2023]
Abstract
We propose an approach to define and measure the statistics of work, internal energy and dissipated heat in a driven quantum system. In our framework the presence of a physical detector arises naturally and work and its statistics can be investigated in the most general case. In particular, we show that the quantum coherence of the initial state can lead to measurable effects on the moments of the work done on the system. At the same time, we recover the known results if the initial state is a statistical mixture of energy eigenstates. Our method can also be applied to measure the dissipated heat in an open quantum system. By sequentially coupling the system to a detector, we can track the energy dissipated in the environment while accessing only the system degrees of freedom.
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Affiliation(s)
- P Solinas
- SPIN-CNR, Via Dodecaneso 33, 16146 Genova, Italy
| | - S Gasparinetti
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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12
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Abstract
We propose the implementation of a Josephson Radiation Comb Generator (JRCG) based on a dc superconducting quantum interference device (SQUID) driven by an external magnetic field. When the magnetic flux crosses a diffraction node of the critical current interference pattern, the superconducting phase undergoes a jump of π and a voltage pulse is generated at the extremes of the SQUID. Under periodic drive this allows one to generate a sequence of sharp, evenly spaced voltage pulses. In the frequency domain, this corresponds to a comb-like structure similar to the one exploited in optics and metrology. With this device it is possible to generate up to several hundreds of harmonics of the driving frequency. For example, a chain of 50 identical high-critical-temperature SQUIDs driven at 1 GHz can deliver up to a 0.5 nW at 200 GHz. The availability of a fully solid-state radiation comb generator such as the JRCG, easily integrable on chip, may pave the way to a number of technological applications, from metrology to sub-millimeter wave generation.
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Affiliation(s)
- P Solinas
- SPIN-CNR, Via Dodecaneso 33, 16146 Genova, Italy
| | - S Gasparinetti
- 1] Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland [2] Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
| | - D Golubev
- 1] Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland [2] Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany
| | - F Giazotto
- NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy
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13
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Gramich V, Gasparinetti S, Solinas P, Ankerhold J. Lamb-shift enhancement and detection in strongly driven superconducting circuits. Phys Rev Lett 2014; 113:027001. [PMID: 25062221 DOI: 10.1103/physrevlett.113.027001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Indexed: 06/03/2023]
Abstract
It is shown that strong driving of a quantum system substantially enhances the Lamb shift induced by broadband reservoirs, which are typical for solid-state devices. By varying drive parameters the impact of environmental vacuum fluctuations with continuous spectral distribution onto system observables can be tuned in a distinctive way. This provides experimentally feasible measurement schemes for the Lamb shift in superconducting circuits based on Cooper pair boxes, where it can be detected either in shifted dressed transition frequencies or in pumped charge currents.
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Affiliation(s)
- Vera Gramich
- Institut für Theoretische Physik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany and Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
| | - Simone Gasparinetti
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland
| | - Paolo Solinas
- Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland and SPIN-CNR, Via Dodecaneso 33, 16146 Genova, Italy
| | - Joachim Ankerhold
- Institut für Theoretische Physik, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
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Gasparinetti S, Solinas P, Pugnetti S, Fazio R, Pekola JP. Environment-governed dynamics in driven quantum systems. Phys Rev Lett 2013; 110:150403. [PMID: 25167233 DOI: 10.1103/physrevlett.110.150403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Indexed: 06/03/2023]
Abstract
We show that the dynamics of a driven quantum system weakly coupled to the environment can exhibit two distinct regimes. While the relaxation basis is usually determined by the system+drive Hamiltonian (system-governed dynamics), we find that under certain conditions it is determined by specific features of the environment, such as, the form of the coupling operator (environment-governed dynamics). We provide an effective coupling parameter describing the transition between the two regimes and discuss how to observe the transition in a superconducting charge pump.
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Affiliation(s)
- S Gasparinetti
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
| | - P Solinas
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland and COMP Centre of Excellence, Department of Applied Physics, Aalto University School of Science, P.O. Box 11000, 00076 Aalto, Finland
| | - S Pugnetti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - R Fazio
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy
| | - J P Pekola
- Low Temperature Laboratory (OVLL), Aalto University, P.O. Box 15100, FI-00076 Aalto, Finland
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Abstract
We propose a new type of interferometry, based on geometric phases accumulated by a periodically driven two-level system undergoing multiple Landau-Zener transitions. As a specific example, we study its implementation in a superconducting charge pump. We find that interference patterns appear as a function of the pumping frequency and the phase bias, and clearly manifest themselves in the pumped charge. We also show that the effects described should persist in the presence of realistic decoherence.
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