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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

We offer theoretical explanations for some recent observations in numerical simulations of quantum random walks (QRW). Specifically, in the case of a QRW on the line with one particle (walker) and two entangled coins, we explain the…

Quantum Physics · Physics 2009-12-11 Chaobin Liu , Nelson Petulante

We investigate continuous-time quantum walks of two indistinguishable particles (bosons, fermions or hard-core bosons) in one-dimensional lattices with nearest-neighbour interactions. The two interacting particles can undergo independent-…

Quantum Physics · Physics 2014-02-17 Xizhou Qin , Yongguan Ke , Xiwen Guan , Zhibing Li , Natan Andrei , Chaohong Lee

We study the quantum walk of two interacting particles on a line with an interface separating two topologically distinct regions. The interaction induces a localization-delocalization transition of the edge state at the interface. We…

Quantum Physics · Physics 2018-09-05 Alberto D. Verga , Ricardo Gabriel Elias

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 investigate the properties of a quantum walk which can simulate the behavior of a spin $1/2$ particle in a model with an ordinary spatial dimension, and one extra dimension with warped geometry between two branes. Such a setup…

Quantum Physics · Physics 2022-09-19 Andreu Anglés-Castillo , Armando Pérez

Quantum walks are well-known for their ballistic dispersion, traveling $\Theta(t)$ away in $t$ steps, which is quadratically faster than a classical random walk's diffusive spreading. In physical implementations of the walk, however, the…

Quantum Physics · Physics 2016-01-25 Thomas G. Wong

We consider a new model of quantum walk on a one-dimensional momentum space that includes both discrete jumps and continuous drift. Its time evolution has two stages; a Markov diffusion followed by localized dynamics. As in the well known…

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

We present a scheme to describe the dynamics of accelerating discrete-time quantum walk for one- and two-particle in position space. We show the effect of acceleration in enhancing the entanglement between the particle and position space in…

Quantum Physics · Physics 2019-07-10 Shivani Singh , Radhakrishnan Balu , Raymond Laflamme , C. M. Chandrashekar

We study the motion of two non-interacting quantum particles performing a random walk on a line and analyze the probability that the two particles are detected at a particular position after a certain number of steps (meeting problem). The…

Quantum Physics · Physics 2007-05-23 M. Stefanak , T. Kiss , I. Jex , B. Mohring

In most widely discussed discrete time quantum walk model, after every unitary shift operator, the particle evolves into the superposition of position space and settles down in one of its basis states, loosing entanglement in the coin space…

Quantum Physics · Physics 2007-05-23 C. M. Chandrashekar

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

The common perception is that strong coupling to the environment will always render the evolution of the system density matrix quasi-classical (in fact, diffusive) in the long time limit. We present here a counter-example, in which a…

Other Condensed Matter · Physics 2007-05-23 Nikolay Prokof'ev , Philip Stamp

When confined to a topological environment consisting of a cycle coupled with a half-line, quantum walks exhibit long-term statistical tendencies which differ dramatically from the tendencies of classical random walks in the same…

Quantum Physics · Physics 2015-06-08 Forrest Ingram-Johnson , Chaobin Liu , Nelson Petulante

Coined quantum walks may be interpreted as the motion in position space of a quantum particle with a spin degree of freedom; the dynamics are determined by iterating a unitary transformation which is the product of a spin transformation and…

Quantum Physics · Physics 2007-05-23 Alex D. Gottlieb , Svante Janson , Petra F. Scudo

We consider asymptotic behaviour of a Hadamard walk on a cycle. For a walk which starts with a state in which all the probability is concentrated on one node, we find the explicit formula for the limiting distribution and discuss its…

Quantum Physics · Physics 2015-06-26 Malgorzata Bednarska , Andrzej Grudka , Pawel Kurzynski , Tomasz Luczak , Antoni Wojcik

We present a discrete-time, one-dimensional quantum walk based on the entanglement between the momentum of ultracold rubidium atoms (the walk space) and two internal atomic states (the "coin" degree of freedom). Our scheme is highly…

Quantum Physics · Physics 2018-09-26 Siamak Dadras , Alexander Gresch , Caspar Groiseau , Sandro Wimberger , Gil S. Summy

A thermodynamic theory is developed to describe the behavior of the entanglement between the coin and position degrees of freedom of the quantum walk on the line. This theory shows that, in spite of the unitary evolution, a steady state is…

Quantum Physics · Physics 2011-08-31 Alejandro Romanelli

We investigate a system of two atoms in an optical lattice, performing a quantum walk by state-dependent shift operations and a coin operation acting on the internal states. The atoms interact, e.g., by cold collisions, whenever they are in…

Quantum walks provide simple models of various fundamental processes. It is pivotal to know when the dynamics underlying a walk lead to quantum advantages just by examining its statistics. A walk with many indistinguishable particles and…

Quantum Physics · Physics 2015-11-03 Magdalena Stobińska , Peter P. Rohde , Paweł Kurzyński