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The evolution of a walker in standard "Discrete-time Quantum Walk (DTQW)" is determined by coin and shift unitary operators. The conditional shift operator shifts the position of the walker to right or left by unit step size while the…

Quantum Physics · Physics 2020-03-03 Rashid Ahmad , Safia Bibi , Uzma Sajjad

The preparation of initial superposition states of discrete-time quantum walks (DTQWs) are necessary for the study and applications of DTQWs. In linear optics, it is easy to prepare initial superposition states of the coin, which are always…

We have recently proposed a two-dimensional quantum walk where the requirement of a higher dimensionality of the coin space is substituted with the alternance of the directions in which the walker can move [C. Di Franco, M. Mc Gettrick, and…

Quantum Physics · Physics 2011-10-27 C. Di Franco , M. Mc Gettrick , T. Machida , Th. Busch

Bell-network states are loop-quantum-gravity states that glue quantum polyhedra with entanglement. We present an algorithm and a code that evaluates the reduced density matrix of a Bell-network state and computes its entanglement entropy.…

General Relativity and Quantum Cosmology · Physics 2019-04-24 Eugenio Bianchi , Pietro Dona , Ilya Vilensky

The generation and control of quantum correlations in high-dimensional systems is a major challenge in the present landscape of quantum technologies. Achieving such non-classical high-dimensional resources will potentially unlock enhanced…

We explore the notion of generated entropy in open quantum systems. We focus on the study of the discrete-time quantum walk on the line, from the entropy production perspective. We argue that the evolution of the coin can be modeled as an…

Quantum Physics · Physics 2020-04-13 Andrés Vallejo , Alejandro Romanelli , Raúl Donangelo , Renato Portugal

For a discrete time quantum walk (QW) on the $N$-cycle, allowing for decoherence on the coin, we derive a number of new results, including an explicit formula for the position probability distribution. For a QW of this type, we show that…

Quantum Physics · Physics 2015-05-13 Chaobin Liu , Nelson Petulante

Classical physics is often a good approximation for quantum systems composed of many interacting particles, although wavepacket dispersion and scattering processes continuously induce delocalization and entanglement. According to…

The quantum walk (QW) is the term given to a family of algorithms governing the evolution of a discrete quantum system and as such has a founding role in the study of quantum computation. We contribute to the investigation of QW phenomena…

Quantum Physics · Physics 2015-07-02 Hao Luo , Peng Xue

We study a model for the entanglement of a two-dimensional reflecting Brownian motion in a bounded region divided into two halves by a wall with three or more small windows. We map the Brownian motion into a Markov Chain on the fundamental…

Probability · Mathematics 2020-10-19 Gage Bonner , Jean-Luc Thiffeault , Benedek Valko

Quantum walks have wide applications in quantum information, such as universal quantum computation, so it is important to explore properties of quantum walks thoroughly. We propose a novel method to implement discrete-time quantum walks…

Quantum Physics · Physics 2022-06-09 Qi-Ping Su , Shi-Chao Wang , Yan Chi , Yong-Nan Sun , Li Yu , Zhe Sun , Franco Nori , Chui-Ping Yang

We study properties of entangled systems in the (mainly non-relativistic) second quantization formalism. This is then applied to interacting and non-interacting bosons and fermions and the differences between the two are discussed. We…

Quantum Physics · Physics 2009-11-10 V. Vedral

We consider two independent quantum walks on separate lines augmented by partial or full swapping of coins after each step. For classical random walks, swapping or not swapping coins makes little difference to the random walk…

Quantum Physics · Physics 2012-02-08 Peng Xue , Barry C. Sanders

The most elementary quantum walk is characterized by a 2-dimensional unitary coin flip matrix, which can be parameterized by 4 real variables. The influence of the choice of the coin flip matrix on the time evolution operator is analysed in…

Quantum Physics · Physics 2015-01-30 Lauri Lehman

The problem of entanglement produced by an arbitrary operator is formulated and a related measure of entanglement production is introduced. This measure of entanglement production satisfies all properties natural for such a characteristic.…

Quantum Physics · Physics 2009-11-10 V. I. Yukalov

Quantifying the entangling capability of quantum operations is a fundamental task in quantum information science. Traditionally, this capability is measured by the entangling power (EP), defined as the average entanglement generated when a…

Quantum Physics · Physics 2026-01-30 Kyoungho Cho , Jeongho Bang

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

Entanglement is a resource central to quantum information (QI). In particular, entanglement shared between two distant parties allows them to do certain tasks that would otherwise be impossible. In this context, we study the effect on the…

Quantum Physics · Physics 2017-08-23 Howard M. Wiseman , Stephen D. Bartlett , John A. Vaccaro

We argue that the degrees of freedom in a d-dimensional CFT can be re-organized in an insightful way by studying observables on the moduli space of causal diamonds (or equivalently, the space of pairs of timelike separated points). This…

High Energy Physics - Theory · Physics 2016-09-02 Jan de Boer , Felix M. Haehl , Michal P. Heller , Robert C. Myers

We use the techniques in symmetric orbifolding to calculate the Entanglement Entropy of a single interval in a two dimensional conformal field theory on a circle which is excited to a pure highest weight state. This is achieved by…

High Energy Physics - Theory · Physics 2012-08-17 Amir Esmaeil Mosaffa