1
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Geier M, Krøjer S, von Oppen F, Marcus CM, Flensberg K, Brouwer PW. Non-Abelian Holonomy of Majorana Zero Modes Coupled to a Chaotic Quantum Dot. PHYSICAL REVIEW LETTERS 2024; 132:036604. [PMID: 38307057 DOI: 10.1103/physrevlett.132.036604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/24/2023] [Accepted: 12/16/2023] [Indexed: 02/04/2024]
Abstract
If a quantum dot is coupled to a topological superconductor via tunneling contacts, each contact hosts a Majorana zero mode in the limit of zero transmission. Close to a resonance and at a finite contact transparency, the resonant level in the quantum dot couples the Majorana modes, but a ground-state degeneracy per fermion parity subspace remains if the number of Majorana modes coupled to the dot is five or larger. Upon varying shape-defining gate voltages while remaining close to resonance, a nontrivial evolution within the degenerate ground-state manifold is achieved. We characterize the corresponding non-Abelian holonomy for a quantum dot with chaotic classical dynamics using random matrix theory and discuss measurable signatures of the non-Abelian time evolution.
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Affiliation(s)
- Max Geier
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Svend Krøjer
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Felix von Oppen
- Dahlem Center for Complex Quantum Systems and Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Charles M Marcus
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Karsten Flensberg
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Piet W Brouwer
- Dahlem Center for Complex Quantum Systems and Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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2
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Das S, Caruso F. A hybrid-qudit representation of digital RGB images. Sci Rep 2023; 13:13671. [PMID: 37608205 PMCID: PMC10444894 DOI: 10.1038/s41598-023-39906-9] [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: 03/24/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023] Open
Abstract
Quantum image processing is an emerging topic in the field of quantum information and technology. In this paper, we propose a new quantum image representation of RGB images with deterministic image retrieval, which is an improvement over all the similar existing representations in terms of using minimum resource. We use two entangled quantum registers constituting of total 7 qutrits to encode the color channels and their intensities. Additionally, we generalize the existing encoding methods by using both qubits and qutrits to encode the pixel positions of a rectangular image. This hybrid-qudit approach aligns well with the current progress of NISQ devices in incorporating higher dimensional quantum systems than qubits. We then describe the image encoding method using higher-order qubit-qutrit gates, and demonstrate the decomposition of these gates in terms of simpler elementary gates. We use the Google Cirq's quantum simulator to verify the image preparation in both the ideal noise-free scenario and in presence of realistic noise modelling. We show that the complexity of the image encoding process is linear in the number of pixels. Lastly, we discuss the image compression and some basic RGB image processing protocols using our representation.
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Affiliation(s)
- Sreetama Das
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, Sesto Fiorentino, 50019, Italy.
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy.
| | - Filippo Caruso
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, Sesto Fiorentino, 50019, Italy
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
- QSTAR and CNR-INO, Largo Enrico Fermi 2, 50125, Firenze, Italy
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3
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Liu FM, Wang C, Chen MC, Chen H, Li SW, Shang ZX, Ying C, Wang JW, Huo YH, Peng CZ, Zhu X, Lu CY, Pan JW. Quantum computer-aided design for advanced superconducting qubit: Plasmonium. Sci Bull (Beijing) 2023; 68:1625-1631. [PMID: 37453825 DOI: 10.1016/j.scib.2023.06.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/14/2023] [Accepted: 06/25/2023] [Indexed: 07/18/2023]
Abstract
Complex quantum electronic circuits can be used to design noise-protected qubits, but their complexity may exceed the capabilities of classical simulation. In such cases, quantum computers are necessary for efficient simulation. In this work, we demonstrate the use of variational quantum computing on a transmon-based quantum processor to simulate a superconducting quantum electronic circuit and design a new type of qubit called "Plasmonium", which operates in the plasmon-transition regime. The fabricated Plasmonium qubits show a high two-qubit gate fidelity of 99.58(3)%, as well as a smaller physical size and larger anharmonicity compared to transmon qubits. These properties make Plasmonium a promising candidate for scaling up multi-qubit devices. Our results demonstrate the potential of using quantum computers to aid in the design of advanced quantum processors.
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Affiliation(s)
- Feng-Ming Liu
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Can Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Ming-Cheng Chen
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.
| | - He Chen
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Shao-Wei Li
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Zhong-Xia Shang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Chong Ying
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Jian-Wen Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Yong-Heng Huo
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Cheng-Zhi Peng
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Xiaobo Zhu
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Chao-Yang Lu
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.
| | - Jian-Wei Pan
- Hefei National Research Center for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China; Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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4
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Hassani F, Peruzzo M, Kapoor LN, Trioni A, Zemlicka M, Fink JM. Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nat Commun 2023; 14:3968. [PMID: 37407570 DOI: 10.1038/s41467-023-39656-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/22/2023] [Indexed: 07/07/2023] Open
Abstract
Currently available quantum processors are dominated by noise, which severely limits their applicability and motivates the search for new physical qubit encodings. In this work, we introduce the inductively shunted transmon, a weakly flux-tunable superconducting qubit that offers charge offset protection for all levels and a 20-fold reduction in flux dispersion compared to the state-of-the-art resulting in a constant coherence over a full flux quantum. The parabolic confinement provided by the inductive shunt as well as the linearity of the geometric superinductor facilitates a high-power readout that resolves quantum jumps with a fidelity and QND-ness of >90% and without the need for a Josephson parametric amplifier. Moreover, the device reveals quantum tunneling physics between the two prepared fluxon ground states with a measured average decay time of up to 3.5 h. In the future, fast time-domain control of the transition matrix elements could offer a new path forward to also achieve full qubit control in the decay-protected fluxon basis.
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Affiliation(s)
- F Hassani
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria.
| | - M Peruzzo
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - L N Kapoor
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - A Trioni
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - M Zemlicka
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - J M Fink
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria.
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5
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Macrì N, Giannelli L, Paladino E, Falci G. Coarse-Grained Effective Hamiltonian via the Magnus Expansion for a Three-Level System. ENTROPY (BASEL, SWITZERLAND) 2023; 25:234. [PMID: 36832601 PMCID: PMC9954943 DOI: 10.3390/e25020234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/18/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Quantum state processing is one of the main tools of quantum technologies. While real systems are complicated and/or may be driven by non-ideal control, they may nevertheless exhibit simple dynamics approximately confined to a low-energy Hilbert subspace. Adiabatic elimination is the simplest approximation scheme allowing us to derive in certain cases an effective Hamiltonian operating in a low-dimensional Hilbert subspace. However, these approximations may present ambiguities and difficulties, hindering a systematic improvement of their accuracy in larger and larger systems. Here, we use the Magnus expansion as a systematic tool to derive ambiguity-free effective Hamiltonians. We show that the validity of the approximations ultimately leverages only on a proper coarse-graining in time of the exact dynamics. We validate the accuracy of the obtained effective Hamiltonians with suitably tailored fidelities of quantum operations.
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Affiliation(s)
- Nicola Macrì
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, 95123 Catania, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Catania, 95123 Catania, Italy
| | - Luigi Giannelli
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, 95123 Catania, Italy
- CNR-IMM, UoS Università, 95123 Catania, Italy
| | - Elisabetta Paladino
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, 95123 Catania, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Catania, 95123 Catania, Italy
- CNR-IMM, UoS Università, 95123 Catania, Italy
| | - Giuseppe Falci
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, 95123 Catania, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Catania, 95123 Catania, Italy
- CNR-IMM, UoS Università, 95123 Catania, Italy
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6
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Hyyppä E, Kundu S, Chan CF, Gunyhó A, Hotari J, Janzso D, Juliusson K, Kiuru O, Kotilahti J, Landra A, Liu W, Marxer F, Mäkinen A, Orgiazzi JL, Palma M, Savytskyi M, Tosto F, Tuorila J, Vadimov V, Li T, Ockeloen-Korppi C, Heinsoo J, Tan KY, Hassel J, Möttönen M. Unimon qubit. Nat Commun 2022; 13:6895. [PMID: 36371435 PMCID: PMC9653402 DOI: 10.1038/s41467-022-34614-w] [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: 05/04/2022] [Accepted: 10/28/2022] [Indexed: 11/13/2022] Open
Abstract
Superconducting qubits seem promising for useful quantum computers, but the currently wide-spread qubit designs and techniques do not yet provide high enough performance. Here, we introduce a superconducting-qubit type, the unimon, which combines the desired properties of increased anharmonicity, full insensitivity to dc charge noise, reduced sensitivity to flux noise, and a simple structure consisting only of a single Josephson junction in a resonator. In agreement with our quantum models, we measure the qubit frequency, ω01/(2π), and increased anharmonicity α/(2π) at the optimal operation point, yielding, for example, 99.9% and 99.8% fidelity for 13 ns single-qubit gates on two qubits with (ω01, α) = (4.49 GHz, 434 MHz) × 2π and (3.55 GHz, 744 MHz) × 2π, respectively. The energy relaxation seems to be dominated by dielectric losses. Thus, improvements of the design, materials, and gate time may promote the unimon to break the 99.99% fidelity target for efficient quantum error correction and possible useful quantum advantage with noisy systems.
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Affiliation(s)
| | - Suman Kundu
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FIN-00076, Aalto, Finland
| | | | - András Gunyhó
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FIN-00076, Aalto, Finland
| | | | | | | | - Olavi Kiuru
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FIN-00076, Aalto, Finland
| | | | | | - Wei Liu
- IQM, Keilaranta 19, 02150, Espoo, Finland
| | | | | | | | | | | | | | | | - Vasilii Vadimov
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FIN-00076, Aalto, Finland
| | - Tianyi Li
- IQM, Keilaranta 19, 02150, Espoo, Finland
| | | | | | | | | | - Mikko Möttönen
- IQM, Keilaranta 19, 02150, Espoo, Finland.
- QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FIN-00076, Aalto, Finland.
- VTT Technical Research Centre of Finland Ltd. & QTF Centre of Excellence, P.O. Box 1000, 02044 VTT, Espoo, Finland.
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7
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Quach JQ, Ralph TC, Munro WJ. Berry Phase from the Entanglement of Future and Past Light Cones: Detecting the Timelike Unruh Effect. PHYSICAL REVIEW LETTERS 2022; 129:160401. [PMID: 36306752 DOI: 10.1103/physrevlett.129.160401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The Unruh effect can not only arise out of the entanglement between modes of left and right Rindler wedges, but also between modes of future and past light cones. We explore the geometric phase resulting from this timelike entanglement between the future and past, showing that it can be captured in a simple Λ system. This provides an alternative paradigm to the Unruh-deWitt detector. The Unruh effect has not been experimentally verified because the accelerations needed to excite a response from Unruh-deWitt detectors are prohibitively large. We demonstrate that a stationary but time-dependent Λ-system detects the timelike Unruh effect with current technology.
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Affiliation(s)
- James Q Quach
- Institute for Photonics and Advanced Sensing and School of Physical Sciences, The University of Adelaide, South Australia 5005, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria 3168, Australia
| | - Timothy C Ralph
- Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - William J Munro
- NTT Basic Research Laboratories & NTT Research Center for Theoretical Quantum Physics, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi, Kanagawa 243-0198, Japan
- National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan
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8
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Gao R, Ku HS, Deng H, Yu W, Xia T, Wu F, Song Z, Wang M, Miao X, Zhang C, Lin Y, Shi Y, Zhao HH, Deng C. Ultrahigh Kinetic Inductance Superconducting Materials from Spinodal Decomposition. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201268. [PMID: 35678176 DOI: 10.1002/adma.202201268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/17/2022] [Indexed: 06/15/2023]
Abstract
Disordered superconducting nitrides with kinetic inductance have long been considered to be leading material candidates for high-inductance quantum-circuit applications. Despite continuing efforts toward reducing material dimensions to increase the kinetic inductance and the corresponding circuit impedance, achieving further improvements without compromising material quality has become a fundamental challenge. To this end, a method to drastically increase the kinetic inductance of superconducting materials via spinodal decomposition while maintaining a low microwave loss is proposed. Epitaxial Ti0.48 Al0.52 N is used as a model system and the utilization of spinodal decomposition to trigger the insulator-to-superconductor transition with a drastically enhanced material disorder is demonstrated. The measured kinetic inductance increases by two to three orders of magnitude compared with the best disordered superconducting nitrides reported to date. This work paves the way for substantially enhancing and deterministically controlling the inductance for advanced superconducting quantum circuits.
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Affiliation(s)
- Ran Gao
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Hsiang-Sheng Ku
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Hao Deng
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Wenlong Yu
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Tian Xia
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Feng Wu
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Zhijun Song
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Minghua Wang
- Westlake Center for Micro/Nano Fabrication, Westlake University, Hangzhou, Zhejiang, 310024, P. R. China
| | - Xiaohe Miao
- Instrumentation and Service Center for Physical Sciences, Westlake University, Hangzhou, Zhejiang, 310024, P. R. China
| | - Chao Zhang
- Instrumentation and Service Center for Physical Sciences, Westlake University, Hangzhou, Zhejiang, 310024, P. R. China
| | - Yue Lin
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Yaoyun Shi
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, WA, 98004, USA
| | - Hui-Hai Zhao
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
| | - Chunqing Deng
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang, 311121, P. R. China
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9
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Bienias P, Boettcher I, Belyansky R, Kollár AJ, Gorshkov AV. Circuit Quantum Electrodynamics in Hyperbolic Space: From Photon Bound States to Frustrated Spin Models. PHYSICAL REVIEW LETTERS 2022; 128:013601. [PMID: 35061450 DOI: 10.1103/physrevlett.128.013601] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Abstract
Circuit quantum electrodynamics is one of the most promising platforms for efficient quantum simulation and computation. In recent groundbreaking experiments, the immense flexibility of superconducting microwave resonators was utilized to realize hyperbolic lattices that emulate quantum physics in negatively curved space. Here we investigate experimentally feasible settings in which a few superconducting qubits are coupled to a bath of photons evolving on the hyperbolic lattice. We compare our numerical results for finite lattices with analytical results for continuous hyperbolic space on the Poincaré disk. We find good agreement between the two descriptions in the long-wavelength regime. We show that photon-qubit bound states have a curvature-limited size. We propose to use a qubit as a local probe of the hyperbolic bath, for example, by measuring the relaxation dynamics of the qubit. We find that, although the boundary effects strongly impact the photonic density of states, the spectral density is well described by the continuum theory. We show that interactions between qubits are mediated by photons propagating along geodesics. We demonstrate that the photonic bath can give rise to geometrically frustrated hyperbolic quantum spin models with finite-range or exponentially decaying interaction.
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Affiliation(s)
- Przemyslaw Bienias
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Igor Boettcher
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
- Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Ron Belyansky
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Alicia J Kollár
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Alexey V Gorshkov
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
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10
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Diniz I, de Sousa R. Intrinsic Photon Loss at the Interface of Superconducting Devices. PHYSICAL REVIEW LETTERS 2020; 125:147702. [PMID: 33064504 DOI: 10.1103/physrevlett.125.147702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
We present a quantum theory of dielectric energy loss arising from the piezoelectric coupling between photons and phonons in superconducting devices. Photon loss is shown to occur predominantly at the interface, where the piezoelectric effect is nonzero even when the materials are perfectly crystalline (epitaxial) and free of two-level system defects. We present explicit numerical calculations for the value of the intrinsic loss tangent at several interfaces to conclude that the T_{1} of superconducting qubits may reach over 10^{4} μs if the device is made with defect-free interfaces.
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Affiliation(s)
- Igor Diniz
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials and Related Technology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, Seropédica CEP 23890-000, Brazil
| | - Rogério de Sousa
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Centre for Advanced Materials and Related Technology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
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11
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Larsen TW, Gershenson ME, Casparis L, Kringhøj A, Pearson NJ, McNeil RPG, Kuemmeth F, Krogstrup P, Petersson KD, Marcus CM. Parity-Protected Superconductor-Semiconductor Qubit. PHYSICAL REVIEW LETTERS 2020; 125:056801. [PMID: 32794832 DOI: 10.1103/physrevlett.125.056801] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire Josephson junctions, taking advantage of the higher harmonic content in the energy-phase relation of few-channel junctions. A symmetric interferometer formed by two such junctions, gate-tuned into balance and frustrated by a half-quantum of applied flux, yields a cos(2φ) Josephson element, reflecting coherent transport of pairs of Cooper pairs. We demonstrate that relaxation of the qubit can be suppressed tenfold by tuning into the protected regime.
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Affiliation(s)
- T W Larsen
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - M E Gershenson
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - L Casparis
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - A Kringhøj
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - N J Pearson
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Theoretische Physik, ETH Zurich, 8093 Zurich, Switzerland
| | - R P G McNeil
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - F Kuemmeth
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - P Krogstrup
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
- Microsoft Quantum Materials Lab-Copenhagen, 2800 Kongens Lyngby, Denmark
| | - K D Petersson
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - C M Marcus
- Center for Quantum Devices and Microsoft Quantum Lab-Copenhagen, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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12
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Grünhaupt L, Spiecker M, Gusenkova D, Maleeva N, Skacel ST, Takmakov I, Valenti F, Winkel P, Rotzinger H, Wernsdorfer W, Ustinov AV, Pop IM. Granular aluminium as a superconducting material for high-impedance quantum circuits. NATURE MATERIALS 2019; 18:816-819. [PMID: 31036961 DOI: 10.1038/s41563-019-0350-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Superconducting quantum information processing machines are predominantly based on microwave circuits with relatively low characteristic impedance, about 100 Ω, and small anharmonicity, which can limit their coherence and logic gate fidelity1,2. A promising alternative is circuits based on so-called superinductors3-6, with characteristic impedances exceeding the resistance quantum RQ = 6.4 kΩ. However, previous implementations of superinductors, consisting of mesoscopic Josephson junction arrays7,8, can introduce unintended nonlinearity or parasitic resonant modes in the qubit vicinity, degrading its coherence. Here, we present a fluxonium qubit design based on a granular aluminium superinductor strip9-11. We show that granular aluminium can form an effective junction array with high kinetic inductance and be in situ integrated with standard aluminium circuit processing. The measured qubit coherence time [Formula: see text] illustrates the potential of granular aluminium for applications ranging from protected qubit designs to quantum-limited amplifiers and detectors.
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Affiliation(s)
- Lukas Grünhaupt
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Martin Spiecker
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Daria Gusenkova
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Nataliya Maleeva
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sebastian T Skacel
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Ivan Takmakov
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- Russian Quantum Center, National University of Science and Technology MISIS, Moscow, Russia
| | - Francesco Valenti
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Patrick Winkel
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Hannes Rotzinger
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Alexey V Ustinov
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Russian Quantum Center, National University of Science and Technology MISIS, Moscow, Russia
| | - Ioan M Pop
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany.
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
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13
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Yan T, Liu BJ, Xu K, Song C, Liu S, Zhang Z, Deng H, Yan Z, Rong H, Huang K, Yung MH, Chen Y, Yu D. Experimental Realization of Nonadiabatic Shortcut to Non-Abelian Geometric Gates. PHYSICAL REVIEW LETTERS 2019; 122:080501. [PMID: 30932607 DOI: 10.1103/physrevlett.122.080501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Indexed: 06/09/2023]
Abstract
When a quantum system is driven slowly through a parametric cycle in a degenerate Hilbert space, the state would acquire a non-Abelian geometric phase, which is stable and forms the foundation for holonomic quantum computation (HQC). However, in the adiabatic limit, the environmental decoherence becomes a significant source of errors. Recently, various nonadiabatic holonomic quantum computation (NHQC) schemes have been proposed, but all at the price of increased sensitivity to control errors. Alternatively, there exist theoretical proposals for speeding up HQC by the technique of "shortcut to adiabaticity" (STA), but no experimental demonstration has been reported so far, as these proposals involve a complicated control of four energy levels simultaneously. Here, we propose and experimentally demonstrate that HQC via shortcut to adiabaticity can be constructed with only three energy levels, using a superconducting qubit in a scalable architecture. With this scheme, all holonomic single-qubit operations can be realized nonadiabatically through a single cycle of state evolution. As a result, we are able to experimentally benchmark the stability of STA+HQC against NHQC in the same platform. The flexibility and simplicity of our scheme makes it also implementable on other systems, such as nitrogen-vacancy center, quantum dots, and nuclear magnetic resonance. Finally, our scheme can be extended to construct two-qubit holonomic entangling gates, leading to a universal set of STAHQC gates.
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Affiliation(s)
- Tongxing Yan
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bao-Jie Liu
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kai Xu
- Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Chao Song
- Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Song Liu
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
| | - Zhensheng Zhang
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
| | - Hui Deng
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhiguang Yan
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hao Rong
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Keqiang Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Man-Hong Yung
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
- Central Research Institute, Huawei Technologies, Shenzhen 518129, China
| | - Yuanzhen Chen
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
| | - Dapeng Yu
- Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
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14
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Hazard TM, Gyenis A, Di Paolo A, Asfaw AT, Lyon SA, Blais A, Houck AA. Nanowire Superinductance Fluxonium Qubit. PHYSICAL REVIEW LETTERS 2019; 122:010504. [PMID: 31012689 DOI: 10.1103/physrevlett.122.010504] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/05/2018] [Indexed: 06/09/2023]
Abstract
We characterize a fluxonium qubit consisting of a Josephson junction inductively shunted with a NbTiN nanowire superinductance. We explain the measured energy spectrum by means of a multimode theory accounting for the distributed nature of the superinductance and the effect of the circuit nonlinearity to all orders in the Josephson potential. Using multiphoton Raman spectroscopy, we address multiple fluxonium transitions, observe multilevel Autler-Townes splitting and measure an excited state lifetime of T_{1}=20 μs. By measuring T_{1} at different magnetic flux values, we find a crossover in the lifetime limiting mechanism from capacitive to inductive losses.
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Affiliation(s)
- T M Hazard
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - A Gyenis
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - A Di Paolo
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - A T Asfaw
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - S A Lyon
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - A Blais
- Institut quantique and Département de Physique, Université de Sherbrooke, Sherbrooke J1K 2R1 Quebec, Canada
- Canadian Institute for Advanced Research, Toronto, M5G 1M1 Ontario, Canada
| | - A A Houck
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
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15
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Grünhaupt L, Maleeva N, Skacel ST, Calvo M, Levy-Bertrand F, Ustinov AV, Rotzinger H, Monfardini A, Catelani G, Pop IM. Loss Mechanisms and Quasiparticle Dynamics in Superconducting Microwave Resonators Made of Thin-Film Granular Aluminum. PHYSICAL REVIEW LETTERS 2018; 121:117001. [PMID: 30265102 DOI: 10.1103/physrevlett.121.117001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Indexed: 06/08/2023]
Abstract
Superconducting high kinetic inductance elements constitute a valuable resource for quantum circuit design and millimeter-wave detection. Granular aluminum (grAl) in the superconducting regime is a particularly interesting material since it has already shown a kinetic inductance in the range of nH/□ and its deposition is compatible with conventional Al/AlOx/Al Josephson junction fabrication. We characterize microwave resonators fabricated from grAl with a room temperature resistivity of 4×10^{3} μΩ cm, which is a factor of 3 below the superconductor to insulator transition, showing a kinetic inductance fraction close to unity. The measured internal quality factors are on the order of Q_{i}=10^{5} in the single photon regime, and we demonstrate that nonequilibrium quasiparticles (QPs) constitute the dominant loss mechanism. We extract QP relaxation times in the range of 1 s and we observe QP bursts every ∼20 s. The current level of coherence of grAl resonators makes them attractive for integration in quantum devices, while it also evidences the need to reduce the density of nonequilibrium QPs.
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Affiliation(s)
- Lukas Grünhaupt
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Nataliya Maleeva
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Sebastian T Skacel
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Martino Calvo
- Université Grenoble Alpes, CNRS, Grenoble INP, Insitut Néel, F-38000 Grenoble, France
| | | | - Alexey V Ustinov
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Russian Quantum Center, National University of Science and Technology MISIS, 119049 Moscow, Russia
| | - Hannes Rotzinger
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Alessandro Monfardini
- Université Grenoble Alpes, CNRS, Grenoble INP, Insitut Néel, F-38000 Grenoble, France
| | - Gianluigi Catelani
- JARA Institute for Quantum Information (PGI-11), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Ioan M Pop
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein Leopoldshafen, Germany
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16
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Lin YH, Nguyen LB, Grabon N, San Miguel J, Pankratova N, Manucharyan VE. Demonstration of Protection of a Superconducting Qubit from Energy Decay. PHYSICAL REVIEW LETTERS 2018; 120:150503. [PMID: 29756871 DOI: 10.1103/physrevlett.120.150503] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/26/2017] [Indexed: 06/08/2023]
Abstract
Long-lived transitions occur naturally in atomic systems due to the abundance of selection rules inhibiting spontaneous emission. By contrast, transitions of superconducting artificial atoms typically have large dipoles, and hence their lifetimes are determined by the dissipative environment of a macroscopic electrical circuit. We designed a multilevel fluxonium artificial atom such that the qubit's transition dipole can be exponentially suppressed by flux tuning, while it continues to dispersively interact with a cavity mode by virtual transitions to the noncomputational states. Remarkably, energy decay time T_{1} grew by 2 orders of magnitude, proportionally to the inverse square of the transition dipole, and exceeded the benchmark value of T_{1}>2 ms (quality factor Q_{1}>4×10^{7}) without showing signs of saturation. The dephasing time was limited by the first-order coupling to flux noise to about 4 μs. Our circuit validated the general principle of hardware-level protection against bit-flip errors and can be upgraded to the 0-π circuit [P. Brooks, A. Kitaev, and J. Preskill, Phys. Rev. A 87, 052306 (2013)PLRAAN1050-294710.1103/PhysRevA.87.052306], adding protection against dephasing and certain gate errors.
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Affiliation(s)
- Yen-Hsiang Lin
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - Long B Nguyen
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - Nicholas Grabon
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - Jonathan San Miguel
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - Natalia Pankratova
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
| | - Vladimir E Manucharyan
- Department of Physics, Joint Quantum Institute, and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA
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