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We study the classical and quantum transport processes on some finite networks and model them by continuous-time random walks (CTRW) and continuous-time quantum walks (CTQW), respectively. We calculate the classical and quantum transition…

Quantum Physics · Physics 2011-04-05 S. Salimi , R. Radgohar , M. M. Soltanzadeh

Quantum walks subject to decoherence generically suffer the loss of their genuine quantum feature, a quadratically faster spreading compared to classical random walks. This intuitive statement has been verified analytically for certain…

Even after decades of research the problem of first passage time statistics for quantum dynamics remains a challenging topic of fundamental and practical importance. Using a projective measurement approach, with a sampling time $\tau$, we…

Statistical Mechanics · Physics 2017-04-05 Harel Friedman , David A. Kessler , Eli Barkai

Noisy intermediate-scale quantum computers (NISQ) are in their childhood, but showing high promise. One main concern for NISQ machines is their inherent noisiness, as the qubit states are subject to disturbances with each algorithmic…

Quantum Physics · Physics 2024-07-08 Wolfgang Nowak , Tim Brünnette , Merel Schalkers , Matthias Möller

We characterize quantumness of the so-called quantum walks (whose dynamics is governed by quantum mechanics) by introducing two computable measures which are stronger than the variance of the walker's position probability distribution. The…

Quantum Physics · Physics 2018-10-09 F. Shahbeigi , S. J. Akhtarshenas , A. T. Rezakhani

We present a Mathematica package, QSWalk, to simulate the time evaluation of Quantum Stochastic Walks (QSWs) on arbitrary directed and weighted graphs. QSWs are a generalization of continuous time quantum walks that incorporate both…

Quantum Physics · Physics 2017-06-07 Peter E. Falloon , Jeremy Rodriguez , Jingbo B. Wang

We formulate three current models of discrete-time quantum walks in a combinatorial way. These walks are shown to be closely related to rotation systems and 1-factorizations of graphs. For two of the models, we compute the traces and total…

Combinatorics · Mathematics 2019-05-17 Chris Godsil , Hanmeng Zhan

Quantum walk (QW) is the quantum analog of the random walk. QW is an integral part of the development of numerous quantum algorithms. Hence, an in-depth understanding of QW helps us to grasp the quantum algorithms. We revisit the…

Quantum Physics · Physics 2021-02-16 Mahesh N. Jayakody , Chandrakala Meena , Priodyuti Pradhan

We study a quantum stochastic neural network (QSNN) based on quantum stochastic walks on a graph, and use gradient descent to update the network parameters. We apply a toy model of QSNN with a few neurons to the problems of function…

Quantum Physics · Physics 2022-04-22 Lu-Ji Wang , Jia-Yi Lin , Shengjun Wu

Discrete-time quantum walks, quantum generalizations of classical random walks, provide a framework for quantum information processing, quantum algorithms and quantum simulation of condensed matter systems. The key property of quantum…

Quantum Physics · Physics 2023-06-07 Rostislav Duda , Moein N. Ivaki , Isac Sahlberg , Kim Pöyhönen , Teemu Ojanen

We analyze a special class of 1-D quantum walks (QWs) realized using optical multi-ports. We assume non-perfect multi-ports showing errors in the connectivity, i.e. with a small probability the multi- ports can connect not to their nearest…

Quantum Physics · Physics 2011-10-06 H. Lavička , V. Potoček , T. Kiss , E. Lutz , I. Jex

Quantum walks contribute significantly to developing quantum algorithms and quantum simulations. Here, we introduce a first of its kind one-dimensional quantum walk in the $d$-dimensional quantum domain, where $d>2$, and show its…

Quantum Physics · Physics 2024-10-04 Amit Saha , Debasri Saha , Amlan Chakrabarti

Quantum walks, in virtue of the coherent superposition and quantum interference, possess exponential superiority over its classical counterpart in applications of quantum searching and quantum simulation. The quantum enhanced power is…

We consider the effect of different unitary noise mechanisms on the evolution of a quantum walk (QW) on a linear chain with a generic coin operation: (i) bit-flip channel noise, restricted to the coin subspace of the QW, and (ii)…

Quantum Physics · Physics 2007-11-27 G. Abal , R. Donangelo , F. Severo , R. Siri

Financial markets are noisy yet contain a latent graph-theoretic structure that can be exploited for superior risk-adjusted returns. We propose a quantum stochastic walk (QSW) optimizer that embeds assets in a weighted graph: nodes…

Portfolio Management · Quantitative Finance 2026-02-05 Yen Jui Chang , Wei-Ting Wang , Yun-Yuan Wang , Chen-Yu Liu , Kuan-Cheng Chen , Ching-Ray Chang

We investigate the evolution of a discrete-time one-dimensional quantum walk driven by a position-dependent coin. The rotation angle which depends upon the position of a quantum particle parameterizes the coin operator. For different values…

Quantum Physics · Physics 2020-08-26 Rashid Ahmad , Uzma Sajjad , Muhammad Sajid

We consider Hamiltonian quantum systems with energy bandwidth \Delta E and show that each measurement that determines the time up to an error \Delta t generates at least the entropy (\hbar/(\Delta t \Delta E))^2/2. Our result describes…

Quantum Physics · Physics 2007-05-23 Dominik Janzing , Thomas Beth

We investigate the quantum walk on the line when decoherences are introduced either through simultaneous measurements of the chirality and particle position, or as a result of broken links. Both mechanisms drive the system to a classical…

Quantum Physics · Physics 2009-11-10 A. Romanelli , R. Siri , G. Abal , A. Auyuanet , R. Donangelo

Quantum walks are expected to provide useful algorithmic tools for quantum computation. This paper introduces absorbing probability and time of quantum walks and gives both numerical simulation results and theoretical analyses on Hadamard…

Quantum Physics · Physics 2009-11-07 Tomohiro Yamasaki , Hirotada Kobayashi , Hiroshi Imai

We introduce a discrete-time quantum random walk (QRW) framework for spatial epidemic modelling on a two-dimensional square lattice and compare its dynamics to classical random-walk SIR models. In our model, each infected site spawns a…

Quantum Physics · Physics 2025-09-15 Sayan Manna , Nikhil Kowshik , Sudebkumar Prasant Pal