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We have investigated temporal fluctuation of superconducting qubits via the time-resolved measurement for an IBM Quantum system. We found that the qubit error rate abruptly changes during specific time intervals. Each high error state…

Quantum Physics · Physics 2025-08-22 Yuta Hirasaki , Shunsuke Daimon , Naoki Kanazawa , Toshinari Itoko , Masao Tokunari , Eiji Saitoh

Critical current fluctuations with a 1/ f spectral density (f is frequency) are potentially a limiting source of intrinsic decoherence in superconducting quantum bits (qubits) based on Josephson tunnel junctions. Prior measurements of this…

Superconductivity · Physics 2007-05-23 Michael Mueck , Matthias Korn , C. G. A. Mugford , J. B. Kycia , John Clarke

Recent phase sensitive experiments on high Tc superconductors, e.g., YBa_2Cu_3O_7 single crystals, have established the d-wave nature of the cuprate materials. Here we discuss how to make use of d-wave Josephson junctions in the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Shiro Kawabata , Satoshi Kashiwaya , Yasuhiro Asano , Yukio Tanaka

Fault-tolerant (FT) computation by using quantum error correction (QEC) is essential for realizing large-scale quantum algorithms. Devices are expected to have enough qubits to demonstrate aspects of fault tolerance in the near future.…

Quantum Physics · Physics 2020-03-24 Lingling Lao , Carmen G. Almudever

In the burgeoning field of quantum computing, the precise design and optimization of quantum pulses are essential for enhancing qubit operation fidelity. This study focuses on refining the pulse engineering techniques for superconducting…

Quantum Physics · Physics 2024-09-13 Annika S. Wiening , Joern Bergendahl , Vicente Leyton-Ortega , Peter Nalbach

Superconducting protected qubits aim to achieve sufficiently low error rates so as to allow realization of error-corrected, utility-scale quantum computers. A recent proposal encodes a protected qubit in the quasicharge degree of freedom of…

Quantum Physics · Physics 2026-01-09 Nicholas M. Christopher , Deniz E. Stiegemann , Abhijeet Alase , Thomas M. Stace

We show that space- and time-correlated single-qubit rotation errors can lead to high-weight errors in a quantum circuit when the rotation angles are drawn from heavy-tailed distributions. This leads to a breakdown of quantum error…

Quantum Physics · Physics 2021-05-26 B. D. Clader , Colin J. Trout , Jeff P. Barnes , Kevin Schultz , Gregory Quiroz , Paraj Titum

We investigate the performance of a three qubit error correcting code in the framework of superconducting qubit implementations. Such a code can recover a quantum state perfectly in the case of dephasing errors but only in situations where…

Superconductivity · Physics 2009-11-13 L. Tornberg , M. Wallquist , G. Johansson , V. S. Shumeiko , G. Wendin

We examine how dissipation and gate timing errors affect the fidelity of a sequence of SWAP gates on a chain of interacting qubits in comparison to noise in the interqubit interaction. Although interqubit interaction noise and gate timing…

Mesoscale and Nanoscale Physics · Physics 2022-04-18 Nathan L. Foulk , Robert E. Throckmorton , S. Das Sarma

Quantum error correction provides a path to large-scale quantum computers, but is built on challenging assumptions about the characteristics of the underlying errors. In particular, the mathematical assumption of independent errors in…

Quantum Physics · Physics 2017-12-15 C. L. Edmunds , C. Hempel , R. Harris , H. Ball , V. Frey , T. M. Stace , M. J. Biercuk

A quantum computer will use the properties of quantum physics to solve certain computational problems much faster than otherwise possible. One promising potential implementation is to use superconducting quantum bits in the circuit quantum…

Quantum Physics · Physics 2013-12-01 Matthew Reed

We compare the effect of single qubit incoherent and coherent errors on the logical error rate of the Steane [[7,1,3]] quantum error correction code by performing an exact full-density-matrix simulation of an error correction step. We find…

Quantum Physics · Physics 2016-11-02 Mauricio Gutiérrez , Conor Smith , Livia Lulushi , Smitha Janardan , Kenneth R. Brown

Crosstalk and several sources of operational interference are invisible when qubit or a gate is calibrated or benchmarked in isolation. These are unlocked during the execution of full quantum circuit applying entangling gates to several…

Quantum Physics · Physics 2022-03-02 Muhammad Ahsan

Protected superconducting qubits such as the $0$-$\pi$ qubit promise to substantially reduce physical error rates. However, a key challenge in the field is designing gates for these qubits that do not compromise their protection, or become…

Quantum Physics · Physics 2026-01-16 Xanda C Kolesnikow , Thomas B Smith , Felix Thomsen , Abhijeet Alase , Andrew C Doherty

Recent proposals for building scalable quantum computational devices in semi-conductor based spin qubits introduce shared control lines in order to reduce the overhead of qubits controls. In principle, noises from the shared controls could…

Quantum Physics · Physics 2024-02-16 Yinan Fang

Scaling up invariably error-prone quantum processors is a formidable challenge. While quantum error correction ultimately promises fault-tolerant operation, the required qubit overhead and error thresholds are daunting, and many codes break…

Quantum Physics · Physics 2023-05-29 Kevin Singh , Conor E. Bradley , Shraddha Anand , Vikram Ramesh , Ryan White , Hannes Bernien

The non-dissipative non-linearity of a Josephson junction converts macroscopic superconducting circuits into artificial atoms, enabling some of the best controlled quantum bits (qubits) today. Three fundamental types of superconducting…

Characterizing and mitigating errors in current noisy intermediate-scale devices is important to improve performance of next generations of quantum hardware. In order to investigate the importance of the different noise mechanisms affecting…

Quantum Physics · Physics 2023-02-14 Gabriele Cenedese , Giuliano Benenti , Maria Bondani

The quasiparticle density observed in low-temperature superconducting circuits is several orders of magnitude larger than the value expected at thermal equilibrium. The tunneling of this excess of quasiparticles across Josephson junctions…

Quantum Physics · Physics 2025-11-03 José Alberto Nava Aquino , Rogério de Sousa

As quantum circuits become more integrated and complex, additional error sources that were previously insignificant start to emerge. Consequently, the fidelity of quantum gates benchmarked under pristine conditions falls short of predicting…