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Quantum computers have the potential to outperform classical computers in a range of computational tasks, such as prime factorisation and unstructured searching. However, real-world quantum computers are subject to noise. Quantifying noise…

Quantum Physics · Physics 2023-03-01 Conrad Strydom , Mark Tame

Superdense Coding is a cornerstone in secure quantum communication, exploiting pre-shared entanglement to encode two classical bits within a single qubit. However, noise and decoherence deteriorate entanglement quality, restricting both…

Quantum Physics · Physics 2025-04-18 Syed Emad Uddin Shubha , Tasnuva Farheen

We present measurements of single-qubit gate errors for a superconducting qubit. Results from quantum process tomography and randomized benchmarking are compared with gate errors obtained from a double pi pulse experiment. Randomized…

Mesoscale and Nanoscale Physics · Physics 2009-03-08 J. M. Chow , J. M. Gambetta , L. Tornberg , Jens Koch , Lev S. Bishop , A. A. Houck , B. R. Johnson , L. Frunzio , S. M. Girvin , R. J. Schoelkopf

In this paper, we describe a tensor network simulation of a neutral atom quantum system under the presence of noise, while introducing a new purity-preserving truncation technique that compromises between the simplicity of the matrix…

Quantum Physics · Physics 2025-06-03 James Allen , Matthew Otten , Stephen Gray , Bryan K. Clark

A quantum phase transition that was recently observed in a high-mobility silicon MOSFET is analyzed in terms of a scaling theory. The most striking characteristic of the transition is a divergence of the thermopower, according to an inverse…

Strongly Correlated Electrons · Physics 2013-10-01 T. R. Kirkpatrick , D. Belitz

Charge qubits formed in double quantum dots represent quintessential two-level systems that enjoy both ease of control and efficient readout. Unfortunately, charge noise can cause rapid decoherence, with typical single-qubit gate fidelities…

Mesoscale and Nanoscale Physics · Physics 2019-03-11 Yuan-Chi Yang , S. N. Coppersmith , Mark Friesen

High-fidelity multi-qubit gates are a critical resource for near-term quantum computing, as they underpin the execution of both quantum algorithms and fault-tolerant protocols. The Toffoli gate (CCNOT), in particular, plays a central role…

Quantum Physics · Physics 2025-09-09 M. AbuGhanem

Quantum phase transitions (QPTs) in coherent Ising machines (CIMs) are studied via a spectral mapping between the one-dimensional XY spin model and a network of degenerate optical parametric oscillators (DOPOs). This exact correspondence…

Quantum Physics · Physics 2025-12-30 Jing-Yi-Ran Jin , Shuang-Quan Ma , Qing Ai

We examine the complementarity among coherence (visibility), predictability, and entanglement for qubit and qutrit systems subjected to noisy quantum channels. Using the system-path entanglement framework, analytical expressions for all…

Quantum Physics · Physics 2025-12-01 Pratidhwani Swain , Ramita Sarkar , Sukanta K. Tripathy , Prasanta K. Panigrahi

Quantum computers are inherently affected by noise. While in the long-term error correction codes will account for noise at the cost of increasing physical qubits, in the near-term the performance of any quantum algorithm should be tested…

The realization of high fidelity quantum gates in a multi-qubit system, with a typical target set at 99.9%, is a critical requirement for the implementation of fault-tolerant quantum computation. To reach this level of fidelity, one needs…

Quantum Physics · Physics 2018-06-27 Yukai Wu , Sheng-Tao Wang , L. -M. Duan

We present a framework that utilizes quantum algorithms, an architecture aware quantum noise model and an ideal simulator to benchmark quantum computers. The benchmark metrics highlight the difference between the quantum computer evolution…

Quantum Physics · Physics 2021-12-20 Konstantinos Georgopoulos , Clive Emary , Paolo Zuliani

We establish an intriguing connection between quantum phase transitions and bifurcations in the reduced fidelity between two different reduced density matrices for quantum lattice many-body systems with symmetry-breaking orders. Our finding…

Strongly Correlated Electrons · Physics 2009-05-20 Jin-Hua Liu , Qian-Qian Shi , Jian-Hui Zhao , Huan-Qiang Zhou

Semiconductor double quantum dot hybrid qubits are promising candidates for high-fidelity quantum computing. However, their performance is limited by charge noise, which is ubiquitous in solid-state devices, and phonon-induced dephasing.…

Mesoscale and Nanoscale Physics · Physics 2019-09-04 Yuan-Chi Yang , S. N. Coppersmith , Mark Friesen

The construction of robust and scalable quantum gates is a uniquely hard problem in the field of quantum computing. Real-world quantum computers suffer from many forms of noise, characterized by the decoherence and relaxation times of a…

Quantum Physics · Physics 2025-07-14 Diego Fuentealba , Jack Dahn , James Steck , Elizabeth Behrman

In this work, we introduce a comprehensive statistical framework for assessing single-qubit quantum teleportation performance beyond the conventional average-fidelity benchmark. At first, we derive a closed-form expression for the full…

Quantum Physics · Physics 2025-10-16 D. G. Bussandri , G. M. Bosyk , P. Crespo Del Amo , K. Życzkowski

Quantum error mitigation (QEM) provides a practical route for estimating reliable observables on noisy intermediate-scale quantum (NISQ) devices. Traditional QEM strategies, including zero-noise extrapolation (ZNE) and Clifford data…

Quantum Physics · Physics 2026-04-21 Huaxin Wang , Xinge Wu , Jiajun Liu , Ruiqing He , Jiandong Shang , Hengliang Guo , Qiang Chen

Understanding error mechanisms in two-qubit gate operations is essential for building high-fidelity quantum processors. While prior studies predominantly treat dephasing noise as either Markovian or predominantly low-frequency, realistic…

We study the ground state fidelity, fidelity susceptibility and quench dynamics of the extended quantum compass model in a transverse field. This model reveals a rich phase diagram which includes several critical surfaces depending on…

Statistical Mechanics · Physics 2016-04-04 R. Jafari

We study error correction type protocols in which a quantum channel encodes logical information into an enlarged Hilbert space. Specifically, we consider channels realized by one dimensional random noisy quantum circuits with spatially…

Quantum Physics · Physics 2026-03-24 Arman Sauliere , Guglielmo Lami , Pedro Ribeiro , Andrea De Luca , Jacopo De Nardis