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A quantum particle evolving by Schr\"odinger's equation contains, from the kinetic energy of the particle, a term in its Hamiltonian proportional to Laplace's operator. In discrete space, this is replaced by the discrete or graph Laplacian,…

Quantum Physics · Physics 2016-09-16 Thomas G. Wong , Luís Tarrataca , Nikolay Nahimov

We present a quantum algorithm for ranking the nodes on a network in their order of importance. The algorithm is based on a directed discrete-time quantum walk, and works on all directed networks. This algorithm can theoretically be applied…

Quantum Physics · Physics 2020-04-02 Prateek Chawla , Roopesh Mangal , C. M. Chandrashekar

Since Grover's seminal work, quantum search has been studied in great detail. In the usual search problem, we have a collection of n items and we would like to find a marked item. We consider a new variant of this problem in which…

Quantum Physics · Physics 2007-05-23 Andris Ambainis

Unstructured search remains as one of the significant challenges in computer science, as classical search algorithms become increasingly impractical for large-scale systems due to their linear time complexity. Quantum algorithms, notably…

Quantum Physics · Physics 2025-05-22 Harishankar Mishra , Asvija Balasubramanyam , Gudapati Naresh Raghava

Quantum walks provide a framework for understanding and designing quantum algorithms that is both intuitive and universal. To leverage the computational power of these walks, it is important to be able to programmably modify the graph a…

Quantum Physics · Physics 2022-09-07 Aaron W. Young , William J. Eckner , Nathan Schine , Andrew M. Childs , Adam M. Kaufman

In this paper, we propose an extension of quantum searches on graphs driven by quantum walks to simplicial complexes. To this end, we newly define a quantum walk on simplicial complex which is an alternative of preceding studies by authors.…

Mathematical Physics · Physics 2017-12-06 Kaname Matsue , Osamu Ogurisu , Etsuo Segawa

A quantum walk on a lattice is a paradigm of a quantum search in a database. The database qubit strings are the lattice sites, qubit rotations are tunneling events, and the target site is tagged by an energy shift. For quantum walks on a…

Quantum Physics · Physics 2025-10-14 Emma C. King , Moritz Linnebacher , Peter P. Orth , Matteo Rizzi , Giovanna Morigi

In previous papers about searches on star graphs several patterns have been made apparent; the speed up only occurs when graphs are "tuned" so that their time step operators have degenerate eigenvalues, and only certain initial states are…

Mathematical Physics · Physics 2015-06-19 Seth S. Cottrell

Grover's search algorithm is the optimal quantum algorithm that can search an unstructured database quadratically faster than any known classical algorithm. The role of entanglement and correlations in the search algorithm have been studied…

Quantum Physics · Physics 2016-11-15 Namit Anand , Arun Kumar Pati

Universal quantum computation can be realised using both continuous-time and discrete-time quantum walks. We present a version based on single particle discrete-time quantum walk to realize multi-qubit computation tasks. The scalability of…

Quantum Physics · Physics 2023-08-21 Prateek Chawla , Shivani Singh , Aman Agarwal , Sarvesh Srinivasan , C. M. Chandrashekar

We study the discrete-time quantum walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and…

Quantum Physics · Physics 2015-03-17 Scott D. Berry , Jingbo B. Wang

We study the quantum walk search algorithm of Shenvi, Kempe and Whaley [PRA 67 052307 (2003)] on data structures of one to two spatial dimensions, on which the algorithm is thought to be less efficient than in three or more spatial…

Quantum Physics · Physics 2010-10-25 Neil B. Lovett , Matthew Everitt , Matthew Trevers , Daniel Mosby , Dan Stockton , Viv Kendon

The spatial search problem consists in minimizing the number of steps required to find a given site in a network, under the restriction that only oracle queries or translations to neighboring sites are allowed. In this paper, a quantum…

Quantum Physics · Physics 2012-05-18 G. Abal , R. Donangelo , F. L. Marquezino , R. Portugal

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

Random walks are a fundamental primitive used in many machine learning algorithms with several applications in clustering and semi-supervised learning. Despite their relevance, the first efficient parallel algorithm to compute random walks…

Distributed, Parallel, and Cluster Computing · Computer Science 2021-12-02 Michael Kapralov , Silvio Lattanzi , Navid Nouri , Jakab Tardos

A framework is presented for the design and analysis of quantum mechanical algorithms, the sqrt(N) step quantum search algorithm is an immediate consequence of this framework. It leads to several other search-type applications - several…

Quantum Physics · Physics 2007-05-23 Lov K. Grover

We set the ground for a theory of quantum walks on graphs- the generalization of random walks on finite graphs to the quantum world. Such quantum walks do not converge to any stationary distribution, as they are unitary and reversible.…

Quantum Physics · Physics 2016-09-08 Dorit Aharonov , Andris Ambainis , Julia Kempe , Umesh Vazirani

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

A new model of quantum random walks is introduced, on lattices as well as on finite graphs. These quantum random walks take into account the behavior of open quantum systems. They are the exact quantum analogues of classical Markov chains.…

Quantum Physics · Physics 2014-02-14 S. Attal , F. Petruccione , C. Sabot , I. Sinayskiy

As quantum machine learning continues to develop at a rapid pace, the importance of ensuring the robustness and efficiency of quantum algorithms cannot be overstated. Our research presents an analysis of quantum randomized smoothing, how…

Quantum Physics · Physics 2024-07-26 Nicola Franco , Marie Kempkes , Jakob Spiegelberg , Jeanette Miriam Lorenz