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Lin WJ, Lu Y, Wen PY, Cheng YT, Lee CP, Lin KT, Chiang KH, Hsieh MC, Chen CY, Chien CH, Lin JJ, Chen JC, Lin YH, Chuu CS, Nori F, Frisk Kockum A, Lin GD, Delsing P, Hoi IC. Deterministic Loading of Microwaves onto an Artificial Atom Using a Time-Reversed Waveform. NANO LETTERS 2022; 22:8137-8142. [PMID: 36200986 PMCID: PMC9615994 DOI: 10.1021/acs.nanolett.2c02578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/28/2022] [Indexed: 06/16/2023]
Abstract
Loading quantum information deterministically onto a quantum node is an important step toward a quantum network. Here, we demonstrate that coherent-state microwave photons with an optimal temporal waveform can be efficiently loaded onto a single superconducting artificial atom in a semi-infinite one-dimensional (1D) transmission-line waveguide. Using a weak coherent state (the number of photons (N) contained in the pulse ≪1) with an exponentially rising waveform, whose time constant matches the decoherence time of the artificial atom, we demonstrate a loading efficiency of 94.2% ± 0.7% from 1D semifree space to the artificial atom. The high loading efficiency is due to time-reversal symmetry: the overlap between the incoming wave and the time-reversed emitted wave is up to 97.1% ± 0.4%. Our results open up promising applications in realizing quantum networks based on waveguide quantum electrodynamics.
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Affiliation(s)
- Wei-Ju Lin
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Yong Lu
- Department
of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96Gothenburg, Sweden
- 3rd
Institute of Physics, IQST, and Research Centre SCoPE, University of Stuttgart, Stuttgart70049, Germany
| | - Ping Yi Wen
- Department
of Physics, National Chung Cheng University, Chiayi621301, Taiwan
| | - Yu-Ting Cheng
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Ching-Ping Lee
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Kuan Ting Lin
- CQSE,
Department of Physics, National Taiwan University, Taipei10617, Taiwan
| | - Kuan Hsun Chiang
- Department
of Physics, National Central University, Jhongli32001, Taiwan
| | - Ming Che Hsieh
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Ching-Yeh Chen
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Chin-Hsun Chien
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Jia Jhan Lin
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Jeng-Chung Chen
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
- Center
for Quantum Technology, National Tsing Hua
University, Hsinchu30013, Taiwan
| | - Yen Hsiang Lin
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
- Center
for Quantum Technology, National Tsing Hua
University, Hsinchu30013, Taiwan
| | - Chih-Sung Chuu
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
- Center
for Quantum Technology, National Tsing Hua
University, Hsinchu30013, Taiwan
| | - Franco Nori
- Theoretical
Quantum Physics Laboratory, RIKEN Cluster
for Pioneering Research, Wako-shi, Saitama351-0198, Japan
- Physics
Department, The University of Michigan, Ann Arbor, Michigan48109-1040, United States
| | - Anton Frisk Kockum
- Department
of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Guin Dar Lin
- CQSE,
Department of Physics, National Taiwan University, Taipei10617, Taiwan
- Physics
Division, National Center for Theoretical
Sciences, Taipei10617, Taiwan
- Trapped-Ion
Quantum Computing Laboratory, Hon Hai Research
Institute, Taipei11492, Taiwan
| | - Per Delsing
- Department
of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Io-Chun Hoi
- Department
of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
- Department
of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR999077, China
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Ask A, Johansson G. Non-Markovian Steady States of a Driven Two-Level System. PHYSICAL REVIEW LETTERS 2022; 128:083603. [PMID: 35275666 DOI: 10.1103/physrevlett.128.083603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 12/20/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
We show that an open quantum system in a non-Markovian environment can reach steady states that it cannot reach in a Markovian environment. As these steady states are unique for the non-Markovian regime, they could offer a simple way of detecting non-Markovianity, as no information about the system's transient dynamics is necessary. In particular, we study a driven two-level system (TLS) in a semi-infinite waveguide. Once the waveguide has been traced out, the TLS sees an environment with a distinct memory time. The memory time enters the equations as a time delay that can be varied to compare a Markovian to a non-Markovian environment. We find that some non-Markovian states show exotic behaviors such as population inversion and steady-state coherence beyond 1/sqrt[8], neither of which is possible for a driven TLS in the Markovian regime, where the time delay is neglected. Additionally, we show how the coherence of quantum interference is affected by time delays in a driven system by extracting the effective Purcell-modified decay rate of a TLS in front of a mirror.
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Affiliation(s)
- Andreas Ask
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-41296 Göteborg, Sweden
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Ju CY, Chou MH, Chen GY, Chen YN. Optical quantum frequency filter based on generalized eigenstates. OPTICS EXPRESS 2020; 28:17868-17880. [PMID: 32679989 DOI: 10.1364/oe.395140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Bound eigenstates and generalized eigenstates (scattering eigenstates) are two kinds of eigenstates in quantum mechanics. In this work, we first introduce a systematic way to regularize a generalized eigenstates by using the Wick rotation. The states that can be regularized are, in fact, Gamow states since they form poles in the scattering matrix but not localized before the Wick rotation. We then demonstrate an example where a bosonic field interacting with an array of two level systems can have Gamow states with positive real eigenenergies, and the scattering spectrum diverges at the eigenenergy. Since the eigenenergies of this kind locate in a real continuous scattering spectrum, from the scattering matrix point of view, these states resemble the bound states in the continuum (BIC). Unlike BIC, however, these states are non-localized in space and possess the frequency-filtering nature which may lead to potential applications in tunable quantum frequency filters for scattering states.
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Lin KT, Hsu T, Lee CY, Hoi IC, Lin GD. Scalable collective Lamb shift of a 1D superconducting qubit array in front of a mirror. Sci Rep 2019; 9:19175. [PMID: 31844102 PMCID: PMC6915749 DOI: 10.1038/s41598-019-55545-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/30/2019] [Indexed: 11/11/2022] Open
Abstract
We theoretically investigate resonant dipole-dipole interaction (RDDI) between artificial atoms in a 1D geometry, implemented by N transmon qubits coupled through a transmission line. Similar to the atomic cases, RDDI comes from exchange of virtual photons of the continuous modes, and causes the so-called collective Lamb shift (CLS). To probe the shift, we effectively set one end of the transmission line as a mirror, and examine the reflection spectrum of the probe field from the other end. Our calculation shows that when a qubit is placed at the node of the standing wave formed by the incident and reflected waves, even though it is considered to be decoupled from the field, it results in large energy splitting in the spectral profile of a resonant qubit located at an antinode. This directly implies the interplay of virtual photon processes and explicitly signals the CLS. We further derive a master equation to describe the system, which can take into account mismatch of participating qubits and dephasing effects. Our calculation also demonstrates the superradiant and subradiant nature of the atomic states, and how the CLS scales when more qubits are involved.
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Affiliation(s)
- Kuan-Ting Lin
- Centre for Quantum Science and Engineering, Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Ting Hsu
- Centre for Quantum Science and Engineering, Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Chen-Yu Lee
- Centre for Quantum Science and Engineering, Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Io-Chun Hoi
- Centre for Quantum Technology and Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Guin-Dar Lin
- Centre for Quantum Science and Engineering, Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
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Chien WC, Hsieh YL, Chen CH, Dubyna D, Wu CS, Kuo W. Optical amplification assisted by two-photon processes in a 3-level transmon artificial atom. OPTICS EXPRESS 2019; 27:36088-36099. [PMID: 31873395 DOI: 10.1364/oe.27.036088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
We experimentally study interactions between two microwave fields mediated by 3-level transmon artificial atom with two-photon processes. The transmon has good selection rule, preventing one-photon transition, but allowing two-photon transition from ground state(0) to 2nd excited state(2). By pumping a control tone in resonance to the transition between 1st(1) and 2nd excited state(2), we control the one-photon transparency for 0 to 1 transition and two-photon transparency for 0 to 2 transition. The results are explained by the Autler-Townes splitting induced by the control microwave. In addition, two possible microwave amplification processes involving two-photon processes are also studied. The 4-wave mixing scheme increases the transmission by 3% while 2-photon optical pumping produces a 11% narrowband increment. All these phenomena can be operated with control and probe tones in a narrow band.
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Wen PY, Lin KT, Kockum AF, Suri B, Ian H, Chen JC, Mao SY, Chiu CC, Delsing P, Nori F, Lin GD, Hoi IC. Large Collective Lamb Shift of Two Distant Superconducting Artificial Atoms. PHYSICAL REVIEW LETTERS 2019; 123:233602. [PMID: 31868475 DOI: 10.1103/physrevlett.123.233602] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Indexed: 06/10/2023]
Abstract
Virtual photons can mediate interaction between atoms, resulting in an energy shift known as a collective Lamb shift. Observing the collective Lamb shift is challenging, since it can be obscured by radiative decay and direct atom-atom interactions. Here, we place two superconducting qubits in a transmission line terminated by a mirror, which suppresses decay. We measure a collective Lamb shift reaching 0.8% of the qubit transition frequency and twice the transition linewidth. We also show that the qubits can interact via the transmission line even if one of them does not decay into it.
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Affiliation(s)
- P Y Wen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - K-T Lin
- CQSE, Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - A F Kockum
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
| | - B Suri
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bengaluru 560012, India
| | - H Ian
- Institute of Applied Physics and Materials Engineering, University of Macau, Macau, China
- UMacau Zhuhai Research Institute, Zhuhai, Guangdong 519031, China
| | - J C Chen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - S Y Mao
- Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30013, Taiwan
| | - C C Chiu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - P Delsing
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - F Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - G-D Lin
- CQSE, Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - I-C Hoi
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
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7
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Koski JV, Landig AJ, Pályi A, Scarlino P, Reichl C, Wegscheider W, Burkard G, Wallraff A, Ensslin K, Ihn T. Floquet Spectroscopy of a Strongly Driven Quantum Dot Charge Qubit with a Microwave Resonator. PHYSICAL REVIEW LETTERS 2018; 121:043603. [PMID: 30095954 DOI: 10.1103/physrevlett.121.043603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Indexed: 06/08/2023]
Abstract
We experimentally investigate a strongly driven GaAs double quantum dot charge qubit weakly coupled to a superconducting microwave resonator. The Floquet states emerging from strong driving are probed by tracing the qubit-resonator resonance condition. In this way, we probe the resonance of a qubit that is driven in an adiabatic, a nonadiabatic, or an intermediate rate, showing distinct quantum features of multiphoton processes and a fringe pattern similar to Landau-Zener-Stückelberg interference. Our resonant detection scheme enables the investigation of novel features when the drive frequency is comparable to the resonator frequency. Models based on the adiabatic approximation, rotating wave approximation, and Floquet theory explain our experimental observations.
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Affiliation(s)
- J V Koski
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - A J Landig
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - A Pályi
- Department of Physics, Budapest University of Technology and Economics, H-1111 Budapest, Hungary
- MTA-BME Exotic Quantum Phases "Momentum" Research Group, Budapest University of Technology and Economics, H-1111 Budapest, Hungary
| | - P Scarlino
- 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
| | - G Burkard
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - A Wallraff
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Ensslin
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland
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Kockum AF, Johansson G, Nori F. Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics. PHYSICAL REVIEW LETTERS 2018; 120:140404. [PMID: 29694115 DOI: 10.1103/physrevlett.120.140404] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Indexed: 06/08/2023]
Abstract
In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2^{N} states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.
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Affiliation(s)
| | - Göran Johansson
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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