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Propagation and interference of quantum-mechanical particles comprise an important part of elementary processes in quantum physics, and their essence can be modeled using a quantum walk, a mathematical concept that describes the motion of a…

Quantum Physics · Physics 2020-05-27 Masaya Tamura , Takashi Mukaiyama , Kenji Toyoda

We put forward a new, versatile and highly-scalable experimental setup for the realization of discrete two-dimensional quantum random walks with a single-qubit coin and tunable degree of decoherence. The proposed scheme makes use of a small…

Quantum Physics · Physics 2012-11-29 Jiří Svozilík , Roberto de Jesús León-Montiel , Juan P. Torres

This paper presents the first experimental evidence of the transition from dynamical localization to delocalization under the influence of a quasi-periodic driving on a quantum system. A quantum kicked rotator is realized by placing cold…

Atomic Physics · Physics 2007-05-23 Jean Ringot , Pascal Szriftgiser , Jean-Claude Garreau , Dominique Delande

Certain continuous-time quantum walks can be viewed as scattering processes. These processes can perform quantum computations, but it is challenging to design graphs with desired scattering behavior. In this paper, we study and construct…

Quantum Physics · Physics 2018-08-02 Andrew M. Childs , David Gosset , Daniel Nagaj , Mouktik Raha , Zak Webb

We consider a one dimensional random walk in random environment that is uniformly biased to one direction. In addition to the transition probability, the jump rate of the random walk is assumed to be spatially inhomogeneous and random. We…

Probability · Mathematics 2018-11-27 Amir Dembo , Ryoki Fukushima , Naoki Kubota

We consider a generalization of a one-dimensional stochastic process known in the physical literature as L\'evy-Lorentz gas. The process describes the motion of a particle on the real line in the presence of a random array of marked points,…

Probability · Mathematics 2016-04-12 Alessandra Bianchi , Giampaolo Cristadoro , Marco Lenci , Marilena Ligabò

In this paper we present closed-form expressions for the wave function that governs the evolution of the discrete-time quantum walk on a line when the coin operator is arbitrary. The formulas were derived assuming that the walker can either…

Quantum Physics · Physics 2015-02-18 Miquel Montero

We advance the previous studies of quantum walks on the line with two coins. Such four-state quantum walks driven by a three-direction shift operator may have nonzero stationary distributions (localization), thus distinguishing themselves…

Quantum Physics · Physics 2011-07-19 Chaobin Liu

Quantum interference can terminate energy growth in a continually kicked system, via a single-particle ergodicity-breaking mechanism known as dynamical localization. The effect of many-body interactions on dynamically localized states,…

We calculate the diffusion coefficients of persistent random walks on cubic and hypercubic lattices, where the direction of a walker at a given step depends on the memory of one or two previous steps. These results are then applied to study…

Statistical Mechanics · Physics 2013-02-07 Thomas Gilbert , Huu Chuong Nguyen , David P Sanders

We consider a random walk in random environment with random holding times, that is, the random walk jumping to one of its nearest neighbors with some transition probability after a random holding time. Both the transition probabilities and…

Probability · Mathematics 2014-12-30 Ryoki Fukushima , Naoki Kubota

We demonstrate a quantum walk with time-dependent coin bias. With this technique we realize an experimental single-photon one-dimensional quantum walk with a linearly-ramped time-dependent coin flip operation and thereby demonstrate two…

Quantum Physics · Physics 2015-08-11 Peng Xue , Rong Zhang , Hao Qin , Xiang Zhan , Zhihao Bian , Jian Li , Barry C. Sanders

We study numerically the behavior of continuous-time quantum walks over networks which are topologically equivalent to square lattices. On short time scales, when placing the initial excitation at a corner of the network, we observe a fast,…

Quantum Physics · Physics 2009-11-11 Oliver Muelken , Antonio Volta , Alexander Blumen

We investigate the quantum walk and the quantum kicked rotor in resonance subjected to noise with a L\'evy waiting time distribution. We find that both systems have a sub-ballistic wave function spreading as shown by a power-law tail of the…

Quantum Physics · Physics 2009-11-13 A. Romanelli , R. Siri , V. Micenmacher

Quantum-resonance ratchets have been realized over the last ten years for the production of directed currents of atoms. These non-dissipative systems are based on the interaction of a Bose-Einstein condensate with an optical standing wave…

We consider a quantum particle (walker) on a line who coherently chooses to jump to the left or right depending on the result of toss of a quantum coin. The lengths of the jumps are considered to be independent and identically distributed…

Quantum Physics · Physics 2019-04-26 Sreetama Das , Shiladitya Mal , Aditi Sen De , Ujjwal Sen

Quantum walks have by now been realized in a large variety of different physical settings. In some of these, particularly with trapped ions, the walk is implemented in phase space, where the corresponding position states are not orthogonal.…

Quantum Physics · Physics 2014-04-02 R. Matjeschk , A. Ahlbrecht , M. Enderlein , Ch. Cedzich , A. H. Werner , M. Keyl , T. Schaetz , R. F. Werner

The discrete time quantum walk defined as a quantum-mechanical analogue of the discrete time random walk have recently been attracted from various and interdisciplinary fields. In this review, the weak limit theorem, that is, the asymptotic…

Quantum Physics · Physics 2013-07-15 Yutaka Shikano

We study a spin-1/2-particle moving on a one dimensional lattice subject to disorder induced by a random, space-dependent quantum coin. The discrete time evolution is given by a family of random unitary quantum walk operators, where the…

Quantum Physics · Physics 2015-05-27 Andre Ahlbrecht , Volkher B. Scholz , Albert H. Werner

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