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We present a procedure for averaging one-parameter random unitary groups and random self-adjoint groups. Central to this is a generalization of the notion of weak convergence of a sequence of measures and the corresponding generalization of…

Mathematical Physics · Physics 2021-07-13 John E. Gough , Yurii N. Orlov , Vsevolod Zh. Sakbaev , Oleg G. Smolyanov

Quantum entanglement is one of the core features of quantum theory. While it is typically revealed by measurements along carefully chosen directions, here we review different methods based on so-called random or randomized measurements.…

Quantum Physics · Physics 2020-11-24 Lukas Knips

The quantum walk is the quantum analogue of the well-known random walk, which forms the basis for models and applications in many realms of science. Its properties are markedly different from the classical counterpart and might lead to…

We show that a quantum walk process can be used to construct and secure quantum memory. More precisely, we show that a localized quantum walk with temporal disorder can be engineered to store the information of a single, unknown qubit on a…

Quantum Physics · Physics 2015-04-22 C. M. Chandrashekar , Th. Busch

Quantum walks are roughly analogous to classical random walks, and like classical walks they have been used to find new (quantum) algorithms. When studying the behavior of large graphs or combinations of graphs it is useful to find the…

Quantum Physics · Physics 2015-10-28 Seth S. Cottrell

Propagation in quantum walks is revisited by showing that very general 1D discrete-time quantum walks with time- and space-dependent coefficients can be described, at the continuous limit, by Dirac fermions coupled to electromagnetic…

Quantum Physics · Physics 2013-07-16 Fabrice Debbasch , Giuseppe Di Molfetta , David Espaze , Vincent Foulonneau

Random walk on the set of irreducible representations of a finite group is investigated. For the symmetric and general linear groups, a sharp convergence rate bound is obtained and a cutoff phenomenon is proved. As related results, an…

Probability · Mathematics 2007-05-23 Jason Fulman

Quantum walks (QWs) exhibit different properties compared with classical random walks (RWs), most notably by linear spreading and localization. In the meantime, random walks that replicate quantum walks, which we refer to as…

Mathematical Physics · Physics 2022-11-01 Tomoki Yamagami , Etsuo Segawa , Nicolas Chauvet , André Röhm , Ryoichi Horisaki , Makoto Naruse

Large unweighted directed graphs are commonly used to capture relations between entities. A fundamental problem in the analysis of such networks is to properly define the similarity or dissimilarity between any two vertices. Despite the…

Machine Learning · Statistics 2015-11-03 Tatsunori B. Hashimoto , Yi Sun , Tommi S. Jaakkola

Quantum walks are known to have nontrivial interactions with absorbing boundaries. In particular it has been shown that an absorbing boundary in the one dimensional quantum walk partially reflects information, as observed by absorption…

Quantum Physics · Physics 2020-03-11 Parker Kuklinski

We quantitatively differentiate between the spreads of discrete-time quantum and classical random walks on a cyclic graph. Due to the closed nature of any cyclic graph, there is additional "collision"- like interference in the quantum…

Quantum Physics · Physics 2020-01-28 Jayanth Jayakumar , Sreetama Das , Aditi Sen De , Ujjwal Sen

As random operations for quantum systems are intensively used in various quantum information tasks, a trustworthy measure of the randomness in quantum operations is highly demanded. The Haar measure of randomness is a useful tool with wide…

Quantum walks exhibit properties without classical analogues. One of those is the phenomenon of asymptotic trapping -- there can be non-zero probability of the quantum walker being localised in a finite part of the underlying graph…

Quantum Physics · Physics 2022-06-22 Jan Mareš , Jaroslav Novotný , Martin Štefaňák , Igor Jex

We study the localization properties, energy spectra and coin-position entanglement of the aperiodic discrete-time quantum walks. The aperiodicity is described by spatially dependent quantum coins distributed on the lattice, whose…

Quantum Physics · Physics 2019-09-11 A. R. C. Buarque , W. S. Dias

The quantum random walk is a possible approach to construct new quantum algorithms. Several groups have investigated the quantum random walk and experimental schemes were proposed. In this paper we present the experimental implementation of…

Quantum Physics · Physics 2009-11-07 Jiangfeng Du , Hui Li , Xiaodong Xu , Mingjun Shi , Jihui Wu , Xianyi Zhou , Rongdian Han

We study localization properties of continuously monitored dynamics and associated measurement-induced phase transitions in disordered quantum many-body systems on the basis of the quantum trajectory approach. By calculating the fidelity…

Statistical Mechanics · Physics 2023-06-09 Kazuki Yamamoto , Ryusuke Hamazaki

This article is concerned with numerical methods to approximate effective coefficients in stochastic homogenization of discrete linear elliptic equations, and their numerical analysis --- which has been made possible by recent contributions…

Numerical Analysis · Mathematics 2012-11-09 A. -C. Egloffe , A. Gloria , J. -C. Mourrat , T. N. Nguyen

We study some spectral properties of random walks on infinite countable amenable groups with an emphasis on locally finite groups, e.g. the infinite symmetric group. On locally finite groups, the random walks under consideration are driven…

Spectral Theory · Mathematics 2016-08-26 Alexander Bendikov , Barbara Bobikau , Christophe Pittet

We show a simulation of quantum random walks with multiple photons using a staggered array of 50/50 beam splitters with a bank of detectors at any desired level. We discuss the multiphoton interference effects that are inherent to this…

Quantum Physics · Physics 2013-04-12 Bryan T Gard , Robert M Cross , Petr M Anisimov , Hwang Lee , Jonathan P Dowling

How self-loops on vertices affect quantum walks is an interesting issue, and self-loops play important roles in quantum walk based algorithms. However, the original model that adjusting the effect of self-loops by changing their number has…

Quantum Physics · Physics 2017-07-04 Huiquan Wang , Jie Zhou , Junjie Wu , Xun Yi