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Quantum error correction plays an important role in fault-tolerant quantum information processing. It is usually difficult to experimentally realize quantum error correction, as it requires multiple qubits and quantum gates with high…

Quantum Physics · Physics 2020-11-10 Qihao Guo , Yuan-Yuan Zhao , Markus Grassl , Xinfang Nie , Guo-Yong Xiang , Tao Xin , Zhang-Qi Yin , Bei Zeng

Recent years have witnessed a controversy over Heisenberg's famous error-disturbance relation. Here we resolve the conflict by way of an analysis of the possible conceptualizations of measurement error and disturbance in quantum mechanics.…

Quantum Physics · Physics 2014-12-24 Paul Busch , Pekka Lahti , Reinhard F Werner

Variational Quantum Algorithms (VQAs) are a promising application for near-term quantum processors, however the quality of their results is greatly limited by noise. For this reason, various error mitigation techniques have emerged to deal…

Quantum Physics · Physics 2020-10-19 George S. Barron , Christopher J. Wood

The imaginary-time evolution of quantum states is integral to various fields, ranging from natural sciences to classical optimization or machine learning. Since simulating quantum imaginary-time evolution generally requires storing an…

Quantum Physics · Physics 2024-01-17 Julien Gacon , Christa Zoufal , Giuseppe Carleo , Stefan Woerner

Realizing a large-scale quantum computer requires hardware platforms that can simultaneously achieve universality, scalability, and fault tolerance. As a viable pathway to meeting these requirements, quantum computation based on…

Quantum Physics · Physics 2022-02-15 Kosuke Fukui , Shuntaro Takeda

In this work, we consider the problem of bounding the values of a covariance function corresponding to a continuous-time stationary stochastic process or signal. Specifically, for two signals whose covariance functions agree on a finite…

Signal Processing · Electrical Eng. & Systems 2021-10-07 Filip Elvander , Johan Karlsson , Toon van Waterschoot

We study a classical model for the accumulation of errors in multi-qubit quantum computations. By modeling the error process in a quantum computation using two coupled Markov chains, we are able to capture a weak form of time-dependency…

Quantum Physics · Physics 2021-04-26 Long Ma , Jaron Sanders

How can we analyze quantum correlations in large and noisy systems without quantum state tomography? An established method is to measure total angular momenta and employ the so-called spin-squeezing inequalities based on their expectations…

Quantum Physics · Physics 2024-08-23 Jan Lennart Bönsel , Satoya Imai , Ye-Chao Liu , Otfried Gühne

We compute the variances of sums in arithmetic progressions of arithmetic functions associated with certain $L$-functions of degree two and higher in $\mathbb{F}_q[t]$, in the limit as $q\to\infty$. This is achieved by establishing…

Number Theory · Mathematics 2017-03-28 Chris Hall , Jonathan P. Keating , Edva Roditty-Gershon

The noise in physical qubits is fundamentally asymmetric: in most devices, phase errors are much more probable than bit flips. We propose a quantum error correcting code which takes advantage of this asymmetry and shows good performance at…

Quantum Physics · Physics 2015-06-26 Lev Ioffe , Marc Mezard

An intrinsic measure of the quality of a variational wave function is given by its overlap with the ground state of the system. We derive a general formula to compute this overlap when quantum dynamics in imaginary time is accessible. The…

Statistical Mechanics · Physics 2007-07-26 Christophe Mora , Xavier Waintal

This note presents a few observations on the nonlocal nature of quantum errors and the expected performance of the recently proposed quantum error-correction codes that are based on the assumption that the errors are either bit-flip or…

Quantum Physics · Physics 2007-05-23 Subhash Kak

Quantum computing uses the physical principles of very small systems to develop computing platforms which can solve problems that are intractable on conventional supercomputers. There are challenges not only in building the required…

Quantum Physics · Physics 2024-11-19 Dieter Jaksch , Peyman Givi , Andrew J. Daley , Thomas Rung

Numerical calculus algorithms which estimate derivatives and integrals from data series acquired either via measurements or by sampling functions are essential in scientific computing. To date, a few quantum algorithms have been developed…

Quantum Physics · Physics 2026-03-23 Jordan Cioni , Fabio Semperlotti

This paper presents a new Bayesian framework for quantifying discretization errors in numerical solutions of ordinary differential equations. By modelling the errors as random variables, we impose a monotonicity constraint on the variances,…

Numerical Analysis · Mathematics 2024-11-14 Yuto Miyatake , Kaoru Irie , Takeru Matsuda

Quantum computers (QCs) must implement quantum error correcting codes (QECCs) to protect their logical qubits from errors, and modeling the effectiveness of QECCs on QCs is an important problem for evaluating the QC architecture. The…

Quantum Physics · Physics 2009-11-13 Eric Chi , Stephen A. Lyon , Margaret Martonosi

In this work we present a novel strategy to evaluate multi-variable integrals with quantum circuits. The procedure first encodes the integration variables into a parametric circuit. The obtained circuit is then derived with respect to the…

Quantum Physics · Physics 2024-07-17 Juan M. Cruz-Martinez , Matteo Robbiati , Stefano Carrazza

We study the joint distribution of the input sum and the output sum of a deterministic transducer. Here, the input of this finite-state machine is a uniformly distributed random sequence. We give a simple combinatorial characterization of…

Combinatorics · Mathematics 2015-04-14 Clemens Heuberger , Sara Kropf , Stephan Wagner

Quantum computing is powerful because unitary operators describing the time-evolution of a quantum system have exponential size in terms of the number of qubits present in the system. We develop a new "Singular value transformation"…

Quantum Physics · Physics 2020-02-21 András Gilyén , Yuan Su , Guang Hao Low , Nathan Wiebe

Due to the fragility of quantum mechanical effects, real quantum computers are plagued by frequent noise effects that cause errors during computations. Quantum error-correcting codes address this problem by providing means to identify and…

Quantum Physics · Physics 2023-01-18 Thomas Grurl , Christoph Pichler , Jürgen Fuß , Robert Wille