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In this article we describe the incoherent and coherent spin and charge dynamics of a single electron quantum dot. We use a stochastic master equation to model the state of the system, as inferred by an observer with access to only the…

Quantum Physics · Physics 2017-11-15 Eliska Greplova , Edward A. Laird , G. Andrew D. Briggs , Klaus Mølmer

We study continuous phase spaces of single spins and develop a complete description of their time evolution. The time evolution is completely specified by so-called star products. We explicitly determine these star products for general spin…

Quantum Physics · Physics 2019-01-11 Bálint Koczor , Robert Zeier , Steffen J. Glaser

In this work, we present a new algorithm for generating quantum circuits that efficiently implement continuous time quantum walks on arbitrary simple sparse graphs. The algorithm, called matching decomposition, works by decomposing a…

Quantum Physics · Physics 2026-01-19 Mostafa Atallah , Alvin Gonzales , Daniel Dilley , Igor Gaidai , Zain H. Saleem , Rebekah Herrman

We present a quantum algorithm for sampling random spanning trees from a weighted graph in $\widetilde{O}(\sqrt{mn})$ time, where $n$ and $m$ denote the number of vertices and edges, respectively. Our algorithm has sublinear runtime for…

Quantum Physics · Physics 2025-04-25 Simon Apers , Minbo Gao , Zhengfeng Ji , Chenghua Liu

Inspired by path integral molecular dynamics, we build a spin model, in terms of spin coherent states, from which we can compute the quantum expectation values of a spin in a constant magnetic field, at finite temperature. This formulation…

Materials Science · Physics 2023-11-02 Thomas Nussle , Stam Nicolis , Joseph Barker

Recent advances in quantum simulators permit unitary evolution interspersed with locally resolved mid-circuit measurements. This paves the way for the observation of large-scale space-time structures in quantum trajectories and opens a…

Here I present a new discrete model of quantum mechanics for relativistic 1-electron systems, in which particle movement is described by a directed space-time graph with attached 4-spinors, but without any continuous wave functions. These…

Quantum Physics · Physics 2007-05-23 Wolfgang Koehler

We introduce a continuous-time quantum walk on an ultrametric space corresponding to the set of p-adic integers and compute its time-averaged probability distribution. It is shown that localization occurs for any location of the ultrametric…

Quantum Physics · Physics 2009-03-24 Norio Konno

This comment is to correct the proof of optimality of quantum spatial search for Erd\H{o}s-R\'enyi graphs presented in `Spatial Search by Quantum Walk is Optimal for Almost all Graphs' (https://doi.org/10.1103/PhysRevLett.116.100501). The…

Quantum Physics · Physics 2020-09-29 Ryszard Kukulski , Adam Glos

A general analytical approach to the statistical description of quantum graph spectra based on the exact periodic orbit expansions of quantum levels is discussed. The exact and approximate expressions obtained in \cite{Anima} for the…

Quantum Physics · Physics 2007-05-23 Yu. Dabaghian

This work proposes a computational procedure that uses a quantum walk in a complete graph to train classical artificial neural networks. The idea is to apply the quantum walk to search the weight set values. However, it is necessary to…

Quantum Physics · Physics 2021-09-09 Luciano S. de Souza , Jonathan H. A. de Carvalho , Tiago A. E. Ferreira

We present several families of graphs that allow both efficient quantum walk implementations and efficient quantum walk based search algorithms. For these graphs, we construct quantum circuits that explicitly implement the full quantum walk…

Quantum Physics · Physics 2014-08-08 B. L. Douglas , J. B. Wang

We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Sean Gryb , Karim Thebault

A quantum algorithm that solves the time-dependent Dirac equation on a digital quantum computer is developed and analyzed. The time evolution is performed by an operator splitting decomposition technique that allows for a mapping of the…

Quantum Physics · Physics 2017-05-03 F. Fillion-Gourdeau , S. MacLean , R. Laflamme

We construct a lattice field theory method for computing the real-time dynamics of spin systems in a thermal bath. This is done by building on previous work of Takano with Schwinger-Keldysh and functional differentiation techniques. We…

Quantum Physics · Physics 2023-10-31 Neill C. Warrington

Quantum walks (QW) are of crucial importance in the development of quantum information processing algorithms. Recently, several quantum algorithms have been proposed to implement network analysis, in particular to rank the centrality of…

Quantum Physics · Physics 2021-01-04 Tong Wu , J. A. Izaac , Zi-Xi Li , Kai Wang , Zhao-Zhong Chen , Shining Zhu , J. B. Wang , Xiao-Song Ma

In order to model realistic quantum devices it is necessary to simulate quantum systems strongly coupled to their environment. To date, most understanding of open quantum systems is restricted either to weak system-bath couplings, or to…

Quantum Physics · Physics 2018-09-25 Aidan Strathearn , Peter Kirton , Dainius Kilda , Jonathan Keeling , Brendon W. Lovett

We describe a simple quantum mechanical method that can be used to obtain accurate numerical results over long time scales for the spin correlation tensor of an electron spin that is hyperfine coupled to a large number of nuclear spins.…

Quantum Physics · Physics 2018-08-13 Lachlan P. Lindoy , David E. Manolopoulos

In papers\cite{js,jsa}, the amplitudes of continuous-time quantum walk on graphs possessing quantum decomposition (QD graphs) have been calculated by a new method based on spectral distribution associated to their adjacency matrix. Here in…

Quantum Physics · Physics 2009-11-13 M. A. Jafarizadeh , S. Salimi , R. Sufiani

Starting from our idea of combining the Feynman path integral spirit and the Dyson series kernel, we find an explicit and general form of time evolution operator that is a $c$-number function and a power series of perturbation including all…

Quantum Physics · Physics 2007-05-23 An Min Wang