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Simulating quantum systems with their environments often requires non-unitary operations, and mapping these to quantum devices often involves expensive dilations or prohibitive measurement costs to achieve desired precisions. Building on…

Quantum Physics · Physics 2025-02-03 Aman Mehta , Scott E. Smart , Joseph Peetz , David A. Mazziotti , Prineha Narang

This article presents the first complete application of a quantum time-marching algorithm for simulating multidimensional linear transport phenomena with arbitrary boundaries, whereby the success probabilities are problem intrinsic. The…

Quantum Physics · Physics 2026-04-13 Sergio Bengoechea , Paul Over , Thomas Rung

Iterative methods based on matrix splittings are useful in solving large sparse linear systems. In this direction, proper splittings and its several extensions are used to deal with singular and rectangular linear systems. In this article,…

Numerical Analysis · Mathematics 2019-07-08 Ashish Kumar Nandi , Jajati Keshari Sahoo , Debasisha Mishra

Iteration method is commonly used in solving linear systems of equations. We present quantum algorithms for the relaxed row and column iteration methods by constructing unitary matrices in the iterative processes, which generalize row and…

Quantum Physics · Physics 2022-06-29 Xiao-Qi Liu , Jing Wang , Ming Li , Shu-Qian Shen , Weiguo Li , Shao-Ming Fei

Channel polarization, originally proposed for binary-input channels, is generalized to arbitrary discrete memoryless channels. Specifically, it is shown that when the input alphabet size is a prime number, a similar construction to that for…

Information Theory · Computer Science 2009-08-04 Eren Sasoglu , Emre Telatar , Erdal Arikan

We present a new method for quantum process tomography. The method enables us to efficiently estimate, with fixed precision, any of the parameters characterizing a quantum channel. It is selective since one can choose to estimate the value…

Quantum Physics · Physics 2008-01-08 Ariel Bendersky , Fernando Pastawski , Juan Pablo Paz

We analyze the estimation of a finite ensemble of quantum bits which have been sent through a depolarizing channel. Instead of using the depolarized qubits directly, we first apply a purification step and show that this improves the…

Quantum Physics · Physics 2009-11-06 Holger Mack , Dietmar G. Fischer , Matthias Freyberger

The design of iterative linear precoding is recently challenged by extremely large aperture array (ELAA) systems, where conventional preconditioning techniques could hardly improve the channel condition. In this paper, it is proposed to…

Signal Processing · Electrical Eng. & Systems 2023-01-27 Jinfei Wang , Yi Ma , Na Yi , Rahim Tafazolli

Matrix product state has become the algorithm of choice when studying one-dimensional interacting quantum many-body systems, which demonstrates to be able to explore the most relevant portion of the exponentially large quantum Hilbert space…

Computational Physics · Physics 2020-06-22 Xiao Shi , Yun Shang , Chu Guo

We propose an iterative method for nonlinear semidefinite programs with box constraints. The search direction in the proposed method utilizes the distance from the current point to the boundary of a feasible set. The computation of the…

Optimization and Control · Mathematics 2015-05-15 Akihiko Komatsu , Makoto Yamashita

We consider a search algorithm for the output distribution that achieves the channel capacity of a discrete memoryless channel. We will propose an algorithm by iterated projections of an output distribution onto affine subspaces in the set…

Information Theory · Computer Science 2016-01-11 Kenji Nakagawa , Kohei Watabe , Takuto Sabu

We discuss efficient methods to optimize the metrological performance over local Hamiltonians in a bipartite quantum system. For a given quantum state, our methods find the best local Hamiltonian for which the state outperforms separable…

Quantum Physics · Physics 2026-05-25 Árpád Lukács , Róbert Trényi , Tamás Vértesi , Géza Tóth

We introduce a structured quantum search algorithm that leverages entanglement maps and a fixed-point method to minimize oracle query complexity in unsorted datasets. By partitioning qubits into rows based on their entanglement order, the…

Quantum Physics · Physics 2025-07-22 Yash Prabhat , Snigdha Thakur , Ankur Raina

Conventional polarimetry, including schemes leveraging entangled light, characterizes optical samples through linear transformations of polarization states. We introduce a two-photon probing approach in which both photons of an entangled…

We experimentally demonstrate a single-qubit decohering quantum channel using linear optics. We implement the channel, whose special cases include both the amplitude-damping channel and the bit-flip channel, using a single, static optical…

Quantum Physics · Physics 2012-03-20 Kent Fisher , Robert Prevedel , Rainer Kaltenbaek , Kevin J. Resch

Quantum cryptography via key distribution mechanisms that utilize quantum entanglement between sender-receiver pairs will form the basis of future large-scale quantum networks. A key engineering challenge in such networks will be the…

Information Theory · Computer Science 2015-05-14 Yixuan Xie , Jun Li , Robert Malaney , Jinhong Yuan

A method to optimize the cost of a quantum channel is developed. The goal is to determine the cheapest channel that produces prescribed output states for a given set of input states. This is essentially a quantum version of optimal…

Quantum Physics · Physics 2021-09-22 Rocco Duvenhage

Quantum computing is emerging as a new computing resource that could be superior to conventional computing for certain classes of optimization problems. However, in principle, most existing approaches to quantum optimization are intended to…

Optimization and Control · Mathematics 2022-01-21 Chin-Yao Chang , Eric Jones , Yiyun Yao , Peter Graf , Rishabh Jain

Channel position finding is the task of determining the location of a single target channel amongst an ensemble of background channels. It has many potential applications, including quantum sensing, quantum reading and quantum spectroscopy.…

Quantum Physics · Physics 2022-06-22 Athena Karsa , Jacques Carolan , Stefano Pirandola

Quantum process tomography (QPT) methods aim at identifying a given quantum process. The present paper focuses on the estimation of a unitary process. This class is of particular interest because quantum mechanics postulates that the…

Quantum Physics · Physics 2024-01-23 François Verdeil , Yannick Deville