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Encoded-Fusion-Based Quantum Computation for High Thresholds with Linear Optics
Authors:
Wooyeong Song,
Nuri Kang,
Yong-Su Kim,
Seung-Woo Lee
Abstract:
We propose a fault-tolerant quantum computation scheme in a measurement-based manner with finite-sized entangled resource states and encoded fusion scheme with linear optics. The encoded-fusion is an entangled measurement devised to enhance the fusion success probability in the presence of losses and errors based on a quantum error-correcting code. We apply an encoded-fusion scheme, which can be p…
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We propose a fault-tolerant quantum computation scheme in a measurement-based manner with finite-sized entangled resource states and encoded fusion scheme with linear optics. The encoded-fusion is an entangled measurement devised to enhance the fusion success probability in the presence of losses and errors based on a quantum error-correcting code. We apply an encoded-fusion scheme, which can be performed with linear optics and active feedforwards to implement the generalized Shor code, to construct a fault-tolerant network configuration in a three-dimensional Raussendorf-Harrington-Goyal lattice based on the surface code. Numerical simulations show that our scheme allows us to achieve up to 10 times higher loss thresholds than nonencoded fusion approaches with limited numbers of photons used in fusion. Our scheme paves an efficient route toward fault-tolerant quantum computing with finite-sized entangled resource states and linear optics.
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Submitted 2 August, 2024;
originally announced August 2024.
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Fault-tolerant quantum computation by hybrid qubits with bosonic cat-code and single photons
Authors:
Jaehak Lee,
Nuri Kang,
Seok-Hyung Lee,
Hyunseok Jeong,
Liang Jiang,
Seung-Woo Lee
Abstract:
Hybridizing different degrees of freedom or physical platforms potentially offers various advantages in building scalable quantum architectures. We here introduce a fault-tolerant hybrid quantum computation by building on the advantages of both discrete-variable (DV) and continuous-variable (CV) systems. Particularly, we define a CV-DV hybrid qubit with bosonic cat-code and single photon, which is…
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Hybridizing different degrees of freedom or physical platforms potentially offers various advantages in building scalable quantum architectures. We here introduce a fault-tolerant hybrid quantum computation by building on the advantages of both discrete-variable (DV) and continuous-variable (CV) systems. Particularly, we define a CV-DV hybrid qubit with bosonic cat-code and single photon, which is implementable in current photonic platforms. By the cat-code encoded in the CV part, the dominant loss errors are readily correctable without multi-qubit encoding, while the logical basis is inherently orthogonal due to the DV part. We design fault-tolerant architectures by concatenating hybrid qubits and an outer DV quantum error correction code such as topological codes, exploring their potential merits in developing scalable quantum computation. We demonstrate by numerical simulations that our scheme is at least an order of magnitude more resource-efficient over all previous proposals in photonic platforms, allowing us to achieve a record-high loss threshold among existing CV and hybrid approaches. We discuss its realization not only in all-photonic platforms but also in other hybrid platforms including superconducting and trapped-ion systems, which allows us to find various efficient routes towards fault-tolerant quantum computing.
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Submitted 7 July, 2026; v1 submitted 31 December, 2023;
originally announced January 2024.
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Asymmetric Fraunhofer pattern in Josephson junctions from heterodimensional superlattice V$_5$S$_8$
Authors:
Juewen Fan,
Bingyan Jiang,
Jiaji Zhao,
Ran Bi,
Jiadong Zhou,
Zheng Liu,
Guang Yang,
Jie Shen,
Fanming Qu,
Li Lu,
Ning Kang,
Xiaosong Wu
Abstract:
Introduction of spin-orbit coupling (SOC) in a Josephson junction (JJ) gives rise to unusual Josephson effects. We investigate JJs based on a newly discovered heterodimensional superlattice V$_5$S$_8$ with a special form of SOC. The unique homointerface of our JJs enables elimination of extrinsic effects due to interfaces and disorder. We observe asymmetric Fraunhofer patterns with respect to both…
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Introduction of spin-orbit coupling (SOC) in a Josephson junction (JJ) gives rise to unusual Josephson effects. We investigate JJs based on a newly discovered heterodimensional superlattice V$_5$S$_8$ with a special form of SOC. The unique homointerface of our JJs enables elimination of extrinsic effects due to interfaces and disorder. We observe asymmetric Fraunhofer patterns with respect to both the perpendicular magnetic field and the current. The asymmetry is influenced by an in-plane magnetic field. Analysis of the pattern points to a nontrivial spatial distribution of the Josephson current that is intrinsic to the SOC in V$_5$S$_8$.
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Submitted 7 June, 2022; v1 submitted 31 March, 2022;
originally announced March 2022.
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Homointerface planar Josephson junction based on inverse proximity effect
Authors:
Juewen Fan,
Bingyan Jiang,
Jiaji Zhao,
Ran Bi,
Jiadong Zhou,
Zheng Liu,
Ning Kang,
Fanming Qu,
Li Lu,
Xiaosong Wu
Abstract:
The quality of a superconductor-normal metal-superconductor Josephson junction (JJ) depends crucially on the transparency of the superconductor-normal metal (S/N) interface. We demonstrate a technique for fabricating planar JJs with perfect S/N interfaces. The technique utilizes a strong inverse proximity effect discovered in Al/V$_5$S$_8$ bilayers, by which the Al layer is driven into the resisti…
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The quality of a superconductor-normal metal-superconductor Josephson junction (JJ) depends crucially on the transparency of the superconductor-normal metal (S/N) interface. We demonstrate a technique for fabricating planar JJs with perfect S/N interfaces. The technique utilizes a strong inverse proximity effect discovered in Al/V$_5$S$_8$ bilayers, by which the Al layer is driven into the resistive state. The highly transparent S/N homointerface and the peculiar normal metal enable the flow of Josephson supercurrent across a 2.9 $μ$m long weak link. Moreover, our JJ exhibits a giant critical current and a large product of the critical current and the normal state resistance.
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Submitted 2 April, 2022; v1 submitted 6 December, 2021;
originally announced December 2021.