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Quantum computation and quantum simulation require a versatile gate set to optimize circuit compilation for practical applications. However, existing platforms are often limited to specific gate types or rely on parametric couplers to…

Quantum Physics · Physics 2026-02-03 Guangze Chen , Anton Frisk Kockum

The study of the boundary between classically simulable and computationally complex quantum dynamics is fundamental to understanding which physical resources may enable enhanced information-processing capabilities. We investigate this…

Quantum Physics · Physics 2026-05-08 Moein N. Ivaki , Matias Karjula , Tapio Ala-Nissila

Variational algorithms such as the Quantum Approximate Optimization Algorithm have attracted attention due to their potential for solving problems using near-term quantum computers. The $ZZ$ interaction typically generates the primitive…

Quantum Physics · Physics 2023-04-28 T. Mueller , T. Stollenwerk , D. Headley , M. Epping , F. K. Wilhelm

Efficiently learning expectation values of a quantum state using classical shadow tomography has become a fundamental task in quantum information theory. In a classical shadows protocol, one measures a state in a chosen basis W after it has…

Quantum Physics · Physics 2025-06-04 Maxwell West , Antonio Anna Mele , Martin Larocca , M. Cerezo

Quantum circuit depth minimization is critical for practical applications of circuit-based quantum computation. In this work, we present a systematic procedure to decompose multiqubit controlled unitary gates, which is essential in many…

Quantum Physics · Physics 2022-10-06 Adenilton J. da Silva , Daniel K. Park

We show how to perform a fault-tolerant universal quantum computation in 2D architectures using only transversal unitary operators and local syndrome measurements. Our approach is based on a doubled version of the 2D color code. It enables…

Quantum Physics · Physics 2015-09-11 Sergey Bravyi , Andrew Cross

We give a careful proof that a parallelized version of adiabatic quantum computation can efficiently simulate universal gate model quantum computation. The proof specifies an explicit parameter-dependent Hamiltonian $H({\lambda})$ that is…

Quantum Physics · Physics 2019-02-20 Ari Mizel

In quantum computing, the indirect measurement of unitary operators such as the Hadamard test plays a significant role in many algorithms. However, in certain cases, the indirect measurement can be reduced to the direct measurement, where a…

Quantum Physics · Physics 2019-08-14 Kosuke Mitarai , Keisuke Fujii

The solving of linear systems provides a rich area to investigate the use of nearer-term, noisy, intermediate-scale quantum computers. In this work, we discuss hybrid quantum-classical algorithms for skewed linear systems for…

Quantum Physics · Physics 2021-04-28 Bujiao Wu , Maharshi Ray , Liming Zhao , Xiaoming Sun , Patrick Rebentrost

We introduce a single-number metric, quantum volume, that can be measured using a concrete protocol on near-term quantum computers of modest size ($n\lesssim 50$), and measure it on several state-of-the-art transmon devices, finding values…

Quantum Physics · Physics 2019-10-14 Andrew W. Cross , Lev S. Bishop , Sarah Sheldon , Paul D. Nation , Jay M. Gambetta

The concrete schemes to realize three types of basic quantum logical gates using linear quadripartite cluster states of optical continuous variables are proposed. The influences of noises and finite squeezing on the computation precision…

Quantum Physics · Physics 2015-05-13 Aihong Tan , Changde Xie , Kunchi Peng

We propose a definition of QNC, the quantum analog of the efficient parallel class NC. We exhibit several useful gadgets and prove that various classes of circuits can be parallelized to logarithmic depth, including circuits for encoding…

Quantum Physics · Physics 2009-09-25 Cristopher Moore , Martin Nilsson

Using electrostatic gates to control the electron positions, we present a new controlled-NOT gate based on quantum dots. The qubit states are chosen to be the spin states of an excess conductor electron in the quantum dot; and the main…

Quantum Physics · Physics 2007-05-23 Cyrus C. Y. Lin , Chopin Soo , Yin-Zhong Wu , Wei-Min Zhang

The optimization of quantum circuit depth is crucial for practical quantum computing, as limited coherence times and error-prone operations constrain executable algorithms. Measurement and feedback operations are fundamental in quantum…

Quantum Physics · Physics 2025-03-21 Wei Zi , Junhong Nie , Xiaoming Sun

Instantaneous two-party quantum computation is a computation process with bipartite input and output, in which there are initial shared entanglement, and the nonlocal interactions are limited to simultaneous classical communication in both…

Quantum Physics · Physics 2023-06-23 Li Yu , Jie Xu , Fuqun Wang , Chui-Ping Yang

We propose a set of Bell-type nonlocal games that can be used to prove an unconditional quantum advantage in an objective and hardware-agnostic manner. In these games, the circuit depth needed to prepare a cyclic cluster state and measure a…

Random quantum states and operations are of fundamental and practical interests. In this work, we investigate the entanglement properties of random hypergraph states, which generalize the notion of graph states by applying generalized…

Quantum Physics · Physics 2023-01-04 You Zhou , Alioscia Hamma

One learned from Gottesman-Knill theorem that the Clifford model of quantum computing \cite{Clark07} may be generated from a few quantum gates, the Hadamard, Phase and Controlled-Z gates, and efficiently simulated on a classical computer.…

Quantum Physics · Physics 2010-04-20 Michel Planat

Quantum error correction is critical to the design and manufacture of scalable quantum computing systems. Recently, there has been growing interest in quantum low-density parity-check codes as a resource-efficient alternative to surface…

Quantum Physics · Physics 2026-03-06 Boren Gu , Andy Zeyi Liu , Armanda O. Quintavalle , Qian Xu , Jens Eisert , Joschka Roffe

Quantum error correction is necessary to perform large-scale quantum computation, but requires extremely large overheads in both space and time. High-rate quantum low-density-parity-check (qLDPC) codes promise a route to reduce qubit…