English
Related papers

Related papers: Szegedy Walk Unitaries for Quantum Maps

200 papers

In this paper, we consider a spectral analysis of discrete time quantum walks on the path. For isospectral coin cases, we show that the time averaged distribution and stationary distributions of the quantum walks are described by the pair…

Quantum Physics · Physics 2018-12-18 Choon-Lin Ho , Yusuke Ide , Norio Konno , Etsuo Segawa , Kentaro Takumi

Closed quantum systems follow a unitary time evolution that can be simulated on quantum computers. By incorporating non-unitary effects via, e.g., measurements on ancilla qubits, these algorithms can be extended to open-system dynamics,…

Quantum Physics · Physics 2025-05-07 Peter J. Eder , Jernej Rudi Finžgar , Sarah Braun , Christian B. Mendl

Quantum computing promises to improve the information processing power to levels unreachable by classical computation. Quantum walks are heading the development of quantum algorithms for searching information on graphs more efficiently than…

Quantum walks can be used either as tools for quantum algorithm development or as entanglement generators, potentially useful to test quantum hardware. We present a novel algorithm based on a discrete Hadamard quantum walk on a line with…

Quantum Physics · Physics 2009-01-27 Salvador E. Venegas-Andraca , Sougato Bose

Quantum walks, both discrete and continuous, serve as fundamental tools in quantum information processing with diverse applications. This work introduces a hybrid quantum walk model that integrates the coin mechanism of discrete walks with…

Quantum Physics · Physics 2025-09-12 Tianen Chen , Yun Shang

A discrete-time staggered quantum walk was recently introduced as a generalization that allows to unify other versions, such as the coined and Szegedy's walk. However, it also produces new forms of quantum walks not covered by previous…

Quantum Physics · Physics 2018-11-14 Bruno Chagas , Renato Portugal , Stefan Boettcher , Etsuo Segawa

Existence of the eigenvalues of the discrete-time quantum walks is deeply related to localization of the walks. We revealed the distributions of the eigenvalues given by the splitted generating function method (the SGF method) of the…

Spectral Theory · Mathematics 2020-02-19 Shimpei Endo , Takako Endo , Takashi Komatsu , Norio Konno

The lackadaisical quantum walk is a discrete-time, coined quantum walk on a graph with a weighted self-loop at each vertex. It uses a generalized Grover coin and the flip-flop shift, which makes it equivalent to Szegedy's quantum Markov…

Quantum Physics · Physics 2020-09-18 Mason L. Rhodes , Thomas G. Wong

Quantum walk is one of the main tools for quantum algorithms. Defined by analogy to classical random walk, a quantum walk is a time-homogeneous quantum process on a graph. Both random and quantum walks can be defined either in continuous or…

Quantum Physics · Physics 2010-01-10 Andrew M. Childs

This paper studies the search for a single arc in a graph using the Szegedy walk. Arc search can be interpreted as finding a quantum particle not only in its position but also with a specific internal state. The quantum walk employed in…

Quantum Physics · Physics 2026-04-22 Sho Kubota , Kiyoto Yoshino

We use quantum walks to construct a new quantum algorithm for element distinctness and its generalization. For element distinctness (the problem of finding two equal items among N given items), we get an O(N^{2/3}) query quantum algorithm.…

Quantum Physics · Physics 2014-05-01 Andris Ambainis

The lackadaisical quantum walk is a lazy version of a discrete-time, coined quantum walk, where each vertex has a weighted self-loop that permits the walker to stay put. They have been used to speed up spatial search on a variety of graphs,…

Quantum Physics · Physics 2022-01-20 Jacob Rapoza , Thomas G. Wong

In this paper, we consider an extended coined Szegedy model and discuss the existence of the point spectrum of induced quantum walks in terms of recurrence properties of the underlying birth and death process. We obtain that if the…

Quantum Physics · Physics 2020-07-03 Yusuke Ide , Norio Konno , Etsuo Segawa

We formulate three current models of discrete-time quantum walks in a combinatorial way. These walks are shown to be closely related to rotation systems and 1-factorizations of graphs. For two of the models, we compute the traces and total…

Combinatorics · Mathematics 2019-05-17 Chris Godsil , Hanmeng Zhan

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

Quantum walks contribute significantly to developing quantum algorithms and quantum simulations. Here, we introduce a first of its kind one-dimensional quantum walk in the $d$-dimensional quantum domain, where $d>2$, and show its…

Quantum Physics · Physics 2024-10-04 Amit Saha , Debasri Saha , Amlan Chakrabarti

A notion of up and down Grover walks on simplicial complexes are proposed and their properties are investigated. These are abstract Szegedy walks, which is a special kind of unitary operators on a Hilbert space. The operators introduced in…

Spectral Theory · Mathematics 2017-07-26 Xin Luo , Tatsuya Tate

The development of quantum algorithms based on quantum versions of random walks is placed in the context of the emerging field of quantum computing. Constructing a suitable quantum version of a random walk is not trivial: pure quantum…

Quantum Physics · Physics 2007-05-23 Viv Kendon

In this work, we present a new algorithm for generating quantum circuits that efficiently implement continuous time quantum walks on arbitrary simple sparse graphs. The algorithm, called matching decomposition, works by decomposing a…

Quantum Physics · Physics 2026-01-19 Mostafa Atallah , Alvin Gonzales , Daniel Dilley , Igor Gaidai , Zain H. Saleem , Rebekah Herrman

We investigate the genuinely quantum features of continuous-time quantum walks by combining a single-time and a multi-time quantifier of nonclassicality. On the one hand, we consider the quantum-classical dynamical distance…

Quantum Physics · Physics 2026-04-15 Paolo Luppi , Claudia Benedetti , Andrea Smirne