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Related papers: Emergent Bifurcations in Quantum Circuit Stability…

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We present a multifractal analysis of time series data obtained by repeatedly running a single-qubit quantum circuit on IBM superconducting quantum computers, in which the measurement outcomes are recorded as the number of zeros. By…

Quantum Physics · Physics 2025-12-23 Mohammadreza Saghafi , Lamine Mili , Karlton Wirsing

Quantum algorithmics with single spins poses serious technological challenges such as precision fabrication, rapid decoherence, atomic-scale addressing and readout. To circumvent atomic-scale challenges, we examine the case of fully…

Mesoscale and Nanoscale Physics · Physics 2023-03-07 Mohamad Niknam , Robert N. Schwartz , Louis-S. Bouchard

We study brick wall quantum circuits enjoying a global fermionic symmetry. The constituent 2-qubit gate, and its fermionic symmetry, derive from a 2-particle scattering matrix in integrable, supersymmetric quantum field theory in 1+1…

Quantum Physics · Physics 2024-09-25 Pietro Richelli , Kareljan Schoutens , Alberto Zorzato

Quantum circuits -- built from local unitary gates and local measurements -- are a new playground for quantum many-body physics and a tractable setting to explore universal collective phenomena far-from-equilibrium. These models have shed…

Quantum Physics · Physics 2024-01-12 Matthew P. A. Fisher , Vedika Khemani , Adam Nahum , Sagar Vijay

Quantifying quantum states' complexity is a key problem in various subfields of science, from quantum computing to black-hole physics. We prove a prominent conjecture by Brown and Susskind about how random quantum circuits' complexity…

In the search for quantum advantage with near-term quantum devices, navigating the optimization landscape is significantly hampered by the barren plateaus phenomenon. This study presents a strategy to overcome this obstacle without changing…

Quantum Physics · Physics 2025-03-11 Yuhan Yao , Yoshihiko Hasegawa

A major challenge in practical quantum computation is the ineludible errors caused by the interaction of quantum systems with their environment. Fault-tolerant schemes, in which logical qubits are encoded by several physical qubits, enable…

Quantum Physics · Physics 2020-12-17 Kai Sun , Jin-Shi Xu , Xiao-Ye Xu , Yong-Jian Han , Chuan-Feng Li , Guang-Can Guo

A critical question for the field of quantum computing in the near future is whether quantum devices without error correction can perform a well-defined computational task beyond the capabilities of state-of-the-art classical computers,…

We study the problem of robust performance of quantum systems under structured uncertainties. A specific feature of closed (Hamiltonian) quantum systems is that their poles lie on the imaginary axis and that neither a coherent controller…

Quantum Physics · Physics 2021-10-12 S G Schirmer , F C Langbein , C A Weidner , E A Jonckheere

A quantum error correcting code protects encoded logical information against errors. Transversal gates are a naturally fault-tolerant way to manipulate logical qubits but cannot be universal themselves. Protocols such as magic state…

Quantum Physics · Physics 2026-02-03 Eric Huang , Pierre-Gabriel Rozon , Arpit Dua , Sarang Gopalakrishnan , Michael J. Gullans

Stabilizer states are a prime resource for a number of applications in quantum information science, such as secret-sharing and measurement-based quantum computation. This motivates us to study the entanglement of noisy stabilizer states…

Quantum Physics · Physics 2024-11-01 Kenneth Goodenough , Aqil Sajjad , Eneet Kaur , Saikat Guha , Don Towsley

Adversarial robustness in quantum classifiers is a critical area of study, providing insights into their performance compared to classical models and uncovering potential advantages inherent to quantum machine learning. In the NISQ era of…

Emerging Technologies · Computer Science 2026-03-09 Pouya Kananian , Hans-Arno Jacobsen

Statistical mechanics is founded on the assumption that all accessible configurations of a system are equally likely. This requires dynamics that explore all states over time, known as ergodic dynamics. In isolated quantum systems, however,…

State-of-the-art single-qubit gates on superconducting transmon qubits can achieve the fidelities required for error-corrected computations. However, parameter fluctuations due to qubit instabilities, environmental changes, and control…

A quantum circuit must be preprocessed before implementing on NISQ devices due to the connectivity constraint. Quantum circuit mapping (QCM) transforms the circuit into an equivalent one that is compliant with the NISQ device's architecture…

Quantum Physics · Physics 2022-07-19 Pengcheng Zhu , Shenggen Zheng , Lihua Wei , Xueyun Cheng , Zhijin Guan , Shiguang Feng

We show how local constraints can globally "shatter" Hilbert space into subsectors, leading to an unexpected dynamics with features reminiscent of both many body localization and quantum scars. A crisp example of this phenomenon is provided…

Statistical Mechanics · Physics 2020-05-20 Vedika Khemani , Rahul Nandkishore

With improved gate calibrations reducing unitary errors, we achieve a benchmarked single-qubit gate fidelity of 99.95% with superconducting qubits in a circuit quantum electrodynamics system. We present a method for distinguishing between…

Quantum Physics · Physics 2016-01-13 Sarah Sheldon , Lev S. Bishop , Easwar Magesan , Stefan Filipp , Jerry M. Chow , Jay M. Gambetta

Qubits encoded in a decoherence-free subsystem and realized in exchange-coupled silicon quantum dots are promising candidates for fault-tolerant quantum computing. Benefits of this approach include excellent coherence, low control…

We consider experimentally feasible chains of trapped ions with pseudo-spin 1/2, and find models that can potentially be used to implement error-resistant quantum computation. Similar in spirit to classical neural networks, the…

Quantum Physics · Physics 2009-10-20 Sibylle Braungardt , Aditi Sen De , Ujjwal Sen , Maciej Lewenstein

Although qubit coherence times and gate fidelities are continuously improving, logical encoding is essential to achieve fault tolerance in quantum computing. In most encoding schemes, correcting or tracking errors throughout the computation…