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We consider quantum walks on the cycle in the non-stationary case where the `coin' operation is allowed to change at each time step. We characterize, in algebraic terms, the set of possible state transfers and prove that, as opposed to the…

Quantum Physics · Physics 2009-11-13 Domenico D'Alessandro , Gianfranco Parlangeli , Francesca Albertini

The lackadaisical quantum walk is a quantum analogue of the lazy random walk obtained by adding a self-loop to each vertex in the graph. We analytically prove that lackadaisical quantum walks can find a unique marked vertex on any regular…

Quantum Physics · Physics 2022-02-01 Peter Høyer , Zhan Yu

Electronic transport through chaotic quantum dots exhibits universal, system independent, properties, consistent with random matrix theory. The quantum transport can also be rooted, via the semiclassical approximation, in sums over the…

Chaotic Dynamics · Physics 2013-03-06 Gregory Berkolaiko , Jack Kuipers

Quantum walks have been shown to have a wide range of applications, from artificial intelligence, to photosynthesis, and quantum transport. Quantum stochastic walks (QSWs) generalize this concept to additional non-unitary evolution. In this…

Quantum Physics · Physics 2021-05-26 Peter K. Schuhmacher , Luke C. G. Govia , Bruno G. Taketani , Frank K. Wilhelm

We clarify the correspondence between the two approaches to quantum graphs: via quantum adjacency matrices and via quantum relations. We show how the choice of a (possibly non-tracial) weight manifests itself on the quantum relation side…

Operator Algebras · Mathematics 2024-12-11 Mateusz Wasilewski

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

We give a short overview over recent developments on quantum graphs and outline the connection between general quantum graphs and so-called quantum random walks.

Quantum Physics · Physics 2015-06-26 Gregor Tanner

We introduce and study peak state transfer, a notion of high state transfer in qubit networks modeled by continuous-time quantum walks. Unlike perfect or pretty good state transfer, peak state transfer does not require fidelity arbitrarily…

Quantum Physics · Physics 2025-10-02 Gabriel Coutinho , Krystal Guo , Vincent Schmeits

We study transport properties of discrete quantum dynamical systems on the lattice, in particular Coined Quantum Walks and the Chalker--Coddington model. We prove existence of a non trivial charge transport and that the absolutely…

Mathematical Physics · Physics 2019-06-20 Joachim Asch , Olivier Bourget , Alain Joye

Quantum and random walks have been shown to be equivalent in the following sense: a time-dependent random walk can be constructed such that its vertex distribution at all time instants is identical to the vertex distribution of any…

Quantum Physics · Physics 2023-06-13 Matheus G. Andrade , Franklin de Lima Marquezino , Daniel R. Figueiredo

One-dimensional discrete-time quantum walks show a rich spectrum of topological phases that have so far been exclusively analysed in momentum space. In this work we introduce an alternative approach to topology which is based on the…

Mesoscale and Nanoscale Physics · Physics 2014-04-30 B. Tarasinski , J. K. Asboth , J. P. Dahlhaus

We characterize the spectrum of the transition matrix for simple random walk on graphs consisting of a finite graph with a finite number of infinite Cayley trees attached. We show that there is a continuous spectrum identical to that for a…

Quantum Physics · Physics 2024-04-16 Bergfinnur Durhuus , Thordur Jonsson , John Wheater

In this paper we study continuous-time quantum walks on Cayley graphs of the symmetric group, and prove various facts concerning such walks that demonstrate significant differences from their classical analogues. In particular, we show that…

Quantum Physics · Physics 2007-05-23 Heath Gerhardt , John Watrous

Perfect transfer of a quantum state through a one-dimensional chain is now well understood, allowing one not only to decide whether a fixed Hamiltonian achieves perfect transfer, but to design a suitable one. We are particularly interested…

Quantum Physics · Physics 2011-08-30 Alastair Kay

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

A new family of discrete-time quantum walks (DTQWs) on the line with an exact discrete $U(N)$ gauge invariance is introduced. It is shown that the continuous limit of these DTQWs, when it exists, coincides with the dynamics of a Dirac…

Quantum Physics · Physics 2025-02-28 Pablo Arnault , Giuseppe Di Molfetta , Marc Brachet , Fabrice Debbasch

Non Commutative Geometry (NCG) is considered in the context of a charged particle moving in a uniform magnetic field. The classical and quantum mechanical treatments are revisited and a new marker of NCG is introduced. This marker is then…

Quantum Physics · Physics 2024-06-19 Fabrice Debbasch

Nowadays, quantum simulation schemes come in two flavours. Either they are continuous-time discrete-space models (a.k.a Hamiltonian-based), pertaining to non-relativistic quantum mechanics. Or they are discrete-spacetime models (a.k.a…

Quantum Physics · Physics 2019-10-18 Giuseppe Di Molfetta , Pablo Arrighi

The two major discrete time formulations for quantum walks, coined and scattering, are unitarily equivalent for arbitrary position dependent transition amplitudes and any topology (PRA {\bf 80}, 052301 (2009)). Although the proof explicit…

Quantum Physics · Physics 2013-04-15 B F Venancio , F M Andrade , M G E da Luz

We make and generalize the observation that summing of probability amplitudes of a discrete-time quantum walk over partitions of the walking graph consistent with the step operator results in a unitary evolution on the reduced graph which…

Quantum Physics · Physics 2020-04-06 Václav Potoček