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We investigate the generation of quantum states and unitary operations that are ``random'' in certain respects. We show how to use such states to estimate the average fidelity, an important measure in the study of implementations of quantum…

Quantum Physics · Physics 2007-05-23 Christoph Dankert

We propose a quantum-assisted framework for solving constrained finite-horizon nonlinear optimal control problems using a barrier Sequential Quadratic Programming (SQP) approach. Within this framework, a quantum subroutine is incorporated…

Quantum Physics · Physics 2025-10-22 Nahid Binandeh Dehaghani , Rafal Wisniewski , A. Pedro Aguiar

We propose a quantum unstructured search algorithm to find the extrema or roots of discrete functions, $f(\mathbf{x})$, such as the objective functions in combinatorial and other discrete optimisation problems. The first step of the Quantum…

Quantum Physics · Physics 2026-01-22 Titos Matsakos , Adrian Lomas

We consider process tomography for unitary quantum channels. Given access to an unknown unitary channel acting on a $\textsf{d}$-dimensional qudit, we aim to output a classical description of a unitary that is $\varepsilon$-close to the…

Quantum Physics · Physics 2024-07-31 Jeongwan Haah , Robin Kothari , Ryan O'Donnell , Ewin Tang

Quadratic unconstrained binary optimization (QUBO) tasks are very important in chemistry, finance, job scheduling, and so on, which can be represented using graph structures, with the variables as nodes and the interaction between them as…

Quantum Physics · Physics 2024-04-10 Yuhan Huang , Ferris Prima Nugraha , Siyuan Jin , Yichi Zhang , Bei Zeng , Qiming Shao

The aim of this paper is to develop novel quantum algorithms for Gaussian process quadrature methods. Gaussian process quadratures are numerical integration methods where Gaussian processes are used as functional priors for the integrands…

Computation · Statistics 2025-02-21 Cristian A. Galvis-Florez , Ahmad Farooq , Simo Särkkä

Quantum Signal Processing (QSP) and Quantum Singular Value Transformation (QSVT) currently stand as the most efficient techniques for implementing functions of block encoded matrices, a central task that lies at the heart of most prominent…

Quantum Physics · Physics 2024-01-22 Danial Motlagh , Nathan Wiebe

We propose an orbital optimized method for unitary coupled cluster theory (OO-UCC) within the variational quantum eigensolver (VQE) framework for quantum computers. OO-UCC variationally determines the coupled cluster amplitudes and also…

Strongly Correlated Electrons · Physics 2020-09-23 Wataru Mizukami , Kosuke Mitarai , Yuya O. Nakagawa , Takahiro Yamamoto , Tennin Yan , Yu-ya Ohnishi

This paper introduces an efficient algorithm for computing the general oscillatory matrix functions. These computations are crucial for solving second-order semi-linear initial value problems. The method is exploited using the scaling and…

Numerical Analysis · Mathematics 2024-06-11 Dongping Li , Xue Wang , Xiuying Zhang

Quantum amplitude estimation is a key sub-routine of a number of quantum algorithms with various applications. We propose an adaptive algorithm for interval estimation of amplitudes. The quantum part of the algorithm is based only on…

Quantum Physics · Physics 2022-06-20 Yunpeng Zhao , Haiyan Wang , Kuai Xu , Yue Wang , Ji Zhu , Feng Wang

We exploit Grover operator of database search algorithm for weight decision algorithm. In this research, weight decision problem is to find an exact weight w from given two weights as w1 and w2 where w1+w2=1 and 0<w1<w2<1. Firstly, if a…

In optimization, one of the well-known classical algorithms is power iterations. Simply stated, the algorithm recovers the dominant eigenvector of some diagonalizable matrix. Since numerous optimization problems can be formulated as an…

Quantum Physics · Physics 2024-04-24 V. Akshay , Ar. Melnikov , A. Termanova , M. R. Perelshtein

We propose a genetic-algorithm-based method to find the unitary transformations for any desired quantum computation. We formulate a simple genetic algorithm by introducing the "genetic parameter vector" of the unitary transformations to be…

Quantum Physics · Physics 2015-01-08 Jeongho Bang , Seokwon Yoo

We describe a quantum algorithm that solves combinatorial optimization problems by quantum simulation of a classical simulated annealing process. Our algorithm exploits quantum walks and the quantum Zeno effect induced by evolution…

Quantum Physics · Physics 2009-02-02 R. D. Somma , S. Boixo , H. Barnum , E. Knill

We transform the problem of solving linear system of equations $A\mathbf{x}=\mathbf{b}$ to a problem of finding the right singular vector with singular value zero of an augmented matrix $C$, and present two quantum algorithms for solving…

Quantum Physics · Physics 2023-01-20 Hefeng Wang , Hua Xiang

A consequent approach is proposed to construct symplectic force-gradient algorithms of arbitrarily high orders in the time step for precise integration of motion in classical and quantum mechanics simulations. Within this approach the basic…

Statistical Mechanics · Physics 2009-11-07 Igor Omelyan , Ihor Mryglod , Reinhard Folk

Fractional operators (derivatives/integrals) are defined via the integration of the functions. When the function is produced by a spanning set of fractional power functions, traditional quadrature rules often need to be revised, failing to…

Numerical Analysis · Mathematics 2025-11-20 Ritu Kumari , Mani Mehra , Abhishek Kumar Singh

This thesis contains contributions to the theory of quantum computation. We first define a new method to efficiently approximate special unitary operators. Specifically, given a special unitary U and a precision {\epsilon} > 0, we show how…

Quantum Physics · Physics 2017-02-17 Neil J. Ross

We describe algorithms to obtain an approximate classical description of a $d$-dimensional quantum state when given access to a unitary (and its inverse) that prepares it. For pure states we characterize the query complexity for…

Quantum Physics · Physics 2022-07-19 Joran van Apeldoorn , Arjan Cornelissen , András Gilyén , Giacomo Nannicini

The Variational Quantum Eigensolver approach to the electronic structure problem on a quantum computer involves measurement of the Hamiltonian expectation value. Formally, quantum mechanics allows one to measure all mutually commuting or…

Quantum Physics · Physics 2020-03-17 Tzu-Ching Yen , Vladyslav Verteletskyi , Artur F. Izmaylov