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Koottandavida A, Tsioutsios I, Kargioti A, Smith CR, Joshi VR, Dai W, Teoh JD, Curtis JC, Frunzio L, Schoelkopf RJ, Devoret MH. Erasure Detection of a Dual-Rail Qubit Encoded in a Double-Post Superconducting Cavity. PHYSICAL REVIEW LETTERS 2024; 132:180601. [PMID: 38759169 DOI: 10.1103/physrevlett.132.180601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/03/2024] [Indexed: 05/19/2024]
Abstract
Qubits with predominantly erasure errors present distinctive advantages for quantum error correction (QEC) and fault-tolerant quantum computing. Logical qubits based on dual-rail encoding that exploit erasure detection have been recently proposed in superconducting circuit architectures, with either coupled transmons or cavities. Here, we implement a dual-rail qubit encoded in a compact, double-post superconducting cavity. Using an auxiliary transmon, we perform erasure detection on the dual-rail subspace. We characterize the behavior of the code space by a novel method to perform joint-Wigner tomography. This is based on modifying the cross-Kerr interaction between the cavity modes and the transmon. We measure an erasure rate of 3.981±0.003 (ms)^{-1} and a residual, postselected dephasing error rate up to 0.17 (ms)^{-1} within the code space. This strong hierarchy of error rates, together with the compact and hardware-efficient nature of this novel architecture, holds promise in realizing QEC schemes with enhanced thresholds and improved scaling.
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Affiliation(s)
- Akshay Koottandavida
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Ioannis Tsioutsios
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Aikaterini Kargioti
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Cassady R Smith
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Vidul R Joshi
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Wei Dai
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - James D Teoh
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Jacob C Curtis
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Luigi Frunzio
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Robert J Schoelkopf
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
| | - Michel H Devoret
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA and Yale Quantum Institute, Yale University, New Haven, Connecticut 06511, USA
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Liu T, Guo BQ, Yu CS, Zhang WN. One-step implementation of a hybrid Fredkin gate with quantum memories and single superconducting qubit in circuit QED and its applications. OPTICS EXPRESS 2018; 26:4498-4511. [PMID: 29475300 DOI: 10.1364/oe.26.004498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/04/2018] [Indexed: 06/08/2023]
Abstract
In a recent remarkable experiment [Sci. Adv. 2, e1501531 (2016)], a 3-qubit quantum Fredkin (i.e., controlled-SWAP) gate was demonstrated by using linear optics. Here we propose a simple experimental scheme by utilizing the dispersive interaction in superconducting quantum circuit to implement a hybrid Fredkin gate with a superconducting flux qubit as the control qubit and two separated quantum memories as the target qudits. The quantum memories considered here are prepared by the superconducting coplanar waveguide resonators or nitrogen-vacancy center ensembles. In particular, it is shown that this Fredkin gate can be realized using a single-step operation and more importantly, each target qudit can be in an arbitrary state with arbitrary degrees of freedom. Furthermore, we show that this experimental scheme has many potential applications in quantum computation and quantum information processing such as generating arbitrary entangled states (discrete-variable states or continuous-variable states) of the two memories, measuring the fidelity and the entanglement between the two memories. With state-of-the-art circuit QED technology, the numerical simulation is performed to demonstrate that two-memory NOON states, entangled coherent states, and entangled cat states can be efficiently synthesized.
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Patel RB, Ho J, Ferreyrol F, Ralph TC, Pryde GJ. A quantum Fredkin gate. SCIENCE ADVANCES 2016; 2:e1501531. [PMID: 27051868 PMCID: PMC4820377 DOI: 10.1126/sciadv.1501531] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/04/2016] [Indexed: 05/22/2023]
Abstract
Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.
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Affiliation(s)
- Raj B. Patel
- CQCT (Centre for Quantum Computation & Communication Technology) and Centre for Quantum Dynamics, Griffith University, Brisbane 4111, Australia
- Corresponding author. E-mail: (R.B.P.); (G.J.P.)
| | - Joseph Ho
- CQCT (Centre for Quantum Computation & Communication Technology) and Centre for Quantum Dynamics, Griffith University, Brisbane 4111, Australia
| | - Franck Ferreyrol
- CQCT (Centre for Quantum Computation & Communication Technology) and Centre for Quantum Dynamics, Griffith University, Brisbane 4111, Australia
- Laboratoire Photonique, Numerique et Nanosciences, Institut d’Optique, CNRS and Université de Bordeaux, 33400 Talence, France
| | - Timothy C. Ralph
- CQCT and School of Mathematics and Physics, University of Queensland, Brisbane 4072, Australia
| | - Geoff J. Pryde
- CQCT (Centre for Quantum Computation & Communication Technology) and Centre for Quantum Dynamics, Griffith University, Brisbane 4111, Australia
- Corresponding author. E-mail: (R.B.P.); (G.J.P.)
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Raheli A, Sahrai M, Namdar A, Sadighi-Bonabi R. Large Kerr index with amplification in an open four-level atomic system with twofold lower levels. APPLIED OPTICS 2015; 54:10256-10263. [PMID: 26836685 DOI: 10.1364/ao.54.010256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper presents a new freedom, which is the result of atomic injection and exit rates from a cavity associated with an open system, thus leading to a remarkable giant Kerr nonlinearity with applications in all-optical switching. The influence of atomic injection and exit rate from the cavity on nonlinear susceptibility of an open four-level Λ-type atomic system with twofold lower levels is investigated. It is found that large Kerr nonlinearity accompanied with probe gain can be obtained by adjusting the atomic injection rates and exit rate from the cavity, which is completely different from those presented in previous closed atomic systems. Phase control of Kerr nonlinearity in such an open atomic system is then studied.
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Rispe A, He B, Simon C. Photon-photon gates in Bose-Einstein condensates. PHYSICAL REVIEW LETTERS 2011; 107:043601. [PMID: 21867002 DOI: 10.1103/physrevlett.107.043601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Indexed: 05/31/2023]
Abstract
It has recently been shown that light can be stored in Bose-Einstein condensates for over a second. Here we propose a method for realizing a controlled phase gate between two stored photons. The photons are both stored in the ground state of the effective trapping potential inside the condensate. The collision-induced interaction is enhanced by adiabatically increasing the trapping frequency and by using a Feshbach resonance. A controlled phase shift of π can be achieved in 1 s or less.
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Affiliation(s)
- Arnaud Rispe
- Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary T2N 1N4, Alberta, Canada
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Zavatta A, D'Angelo M, Parigi V, Bellini M. Remote preparation of arbitrary time-encoded single-photon ebits. PHYSICAL REVIEW LETTERS 2006; 96:020502. [PMID: 16486554 DOI: 10.1103/physrevlett.96.020502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Indexed: 05/06/2023]
Abstract
We propose and experimentally verify a novel method for the remote preparation of entangled bits (ebits) made of a single photon coherently delocalized in two well-separated temporal modes. The proposed scheme represents a remotely tunable source for tailoring arbitrary ebits, whether maximally or nonmaximally entangled, which is highly desirable for applications in quantum information technology. The remotely prepared ebit is studied by performing homodyne tomography with an ultrafast balanced homodyne detection scheme recently developed in our laboratory.
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Affiliation(s)
- Alessandro Zavatta
- Istituto Nazionale di Ottica Applicata, CNR, Largo Enrico Fermi, 6, I-50125 Florence, Italy
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Giorgi G, Mataloni P, De Martini F. Frequency hopping in quantum interferometry: efficient up-down conversion for qubits and ebits. PHYSICAL REVIEW LETTERS 2003; 90:027902. [PMID: 12570581 DOI: 10.1103/physrevlett.90.027902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2002] [Indexed: 05/24/2023]
Abstract
A novel Mach-Zehnder interferometer terminated at two different frequencies realizes in a quantum regime the nonlinear frequency conversion of optical quantum superposition states. The information-preserving character of the relevant unitary transformation has been experimentally demonstrated for input qubits and ebits. Besides its own intrinsic fundamental interest, the new scheme is expected to find important applications in modern quantum information technology.
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Affiliation(s)
- G Giorgi
- Dipartimento di Fisica and Istituto Nazionale per la Fisica della Materia, Università di Roma La Sapienza, Roma, 00185, Italy
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Howell JC, Yeazell JA. Quantum computation through entangling single photons in multipath interferometers. PHYSICAL REVIEW LETTERS 2000; 85:198-201. [PMID: 10991193 DOI: 10.1103/physrevlett.85.198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2000] [Indexed: 05/23/2023]
Abstract
Single-photon interferometry has been used to simulate quantum computations. Its use has been limited to studying few-bit applications due to rapid growth in physical size with numbers of bits. We propose a hybrid approach that employs n photons, each having L degrees of freedom yielding L(n) basis states. The photons are entangled via a quantum nondemolition measurement. This approach introduces the essential element of quantum computing, that is, entanglement into the interferometry. Using these techniques, we demonstrate a controlled-NOT gate and a Grover's search circuit. These ideas are also applicable to the study of nonlocal correlations in many dimensions.
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Affiliation(s)
- JC Howell
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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