English
Related papers

Related papers: Of Shadows and Gaps in Spatial Search

200 papers

Continuous-time quantum walks are natural tools for spatial search, where one searches for a marked vertex in a graph. Sometimes, the structure of the graph causes the walker to get trapped, such that the probability of finding the marked…

Quantum Physics · Physics 2016-08-10 Thomas G. Wong , Pascal Philipp

We study spatial search with continuous-time quantum walks on real-world complex networks. We use smaller replicas of the Internet network obtained with a recent geometric renormalization method introduced by Garc\'ia-P\'erez et al., Nat.…

Quantum Physics · Physics 2022-12-19 Joonas Malmi , Matteo A. C. Rossi , Guillermo García-Pérez , Sabrina Maniscalco

In the typical spatial search problems solved by continuous-time quantum walk, changing the location of the marked vertices does not alter the search problem. In this paper, we consider search when this is no longer true. In particular, we…

Quantum Physics · Physics 2016-04-11 Thomas G. Wong

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

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

We present a novel methodological framework for quantum spatial search, generalising the Childs & Goldstone ($\mathcal{CG}$) algorithm via alternating applications of marked-vertex phase shifts and continuous-time quantum walks. We…

Quantum Physics · Physics 2021-09-30 S. Marsh , J. B. Wang

In the paper, we investigated the influence of local and global interaction on the efficiency of continuous-time quantum spatial search. To do so, we analyzed numerically chimera graph, which is defined as 2D grid with each node replaced by…

Quantum Physics · Physics 2019-12-20 Adam Glos , Tomasz Januszek

Searching for an unknown marked vertex on a given graph (also known as spatial search) is an extensively discussed topic in the area of quantum algorithms, with a plethora of results based on different quantum walk models and targeting…

Quantum Physics · Physics 2025-06-27 Guanzhong Li , Jingquan Luo , Shiguang Feng , Lvzhou Li

Grover's quantum search algorithm provides a way to speed up combinatorial search, but is not directly applicable to searching a physical database. Nevertheless, Aaronson and Ambainis showed that a database of N items laid out in d spatial…

Quantum Physics · Physics 2007-05-23 Andrew M. Childs , Jeffrey Goldstone

We address quantum spatial search on graphs and its implementation by continuous-time quantum walks in the presence of dynamical noise. In particular, we focus on search on the complete graph and on the star graph of order $N$, proving that…

Quantum Physics · Physics 2018-11-29 Marco Cattaneo , Matteo A. C. Rossi , Matteo G. A. Paris , Sabrina Maniscalco

Local search is a powerful heuristic in optimization and computer science, the complexity of which has been studied in the white box and black box models. In the black box model, we are given a graph $G = (V,E)$ and oracle access to a…

Computational Complexity · Computer Science 2024-11-19 Simina Brânzei , Nicholas J. Recker

Local search is a powerful heuristic in optimization and computer science, the complexity of which was studied in the white box and black box models. In the black box model, we are given a graph $G = (V,E)$ and oracle access to a function…

Computational Complexity · Computer Science 2023-08-16 Simina Brânzei , Davin Choo , Nicholas Recker

Kronecker graphs, obtained by repeatedly performing the Kronecker product of the adjacency matrix of an "initiator" graph with itself, have risen in popularity in network science due to their ability to generate complex networks with…

Quantum Physics · Physics 2018-08-01 Thomas G. Wong , Konstantin Wünscher , Joshua Lockhart , Simone Severini

Recently similarity graphs became the leading paradigm for efficient nearest neighbor search, outperforming traditional tree-based and LSH-based methods. Similarity graphs perform the search via greedy routing: a query traverses the graph…

Machine Learning · Computer Science 2019-05-28 Dmitry Baranchuk , Dmitry Persiyanov , Anton Sinitsin , Artem Babenko

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

We study the average probability that a discrete-time quantum walk finds a marked vertex on a graph. We first show that, for a regular graph, the spectrum of the transition matrix is determined by the weighted adjacency matrix of an…

Combinatorics · Mathematics 2021-08-24 Hanmeng Zhan

A randomly walking quantum particle evolving by Schr\"odinger's equation searches on $d$-dimensional cubic lattices in $O(\sqrt{N})$ time when $d \ge 5$, and with progressively slower runtime as $d$ decreases. This suggests that graph…

Quantum Physics · Physics 2015-03-20 David A. Meyer , Thomas G. Wong

Applications in many domains require processing moving object trajectories. In this work, we focus on a trajectory similarity search that finds all trajectories within a given distance of a query trajectory over a time interval, which we…

Distributed, Parallel, and Cluster Computing · Computer Science 2014-10-13 Michael Gowanlock , Henri Casanova

Continuous-time quantum walks are typically effected by either the discrete Laplacian or the adjacency matrix. In this paper, we explore a third option: the signless Laplacian, which has applications in algebraic graph theory and may arise…

Quantum Physics · Physics 2025-03-26 Molly E. McLaughlin , Thomas G. Wong

Temporal graphs are graphs where the edge set can change in each time step, and the vertex set stays the same. Exploration of temporal graphs whose snapshot in each time step is a connected graph, called connected temporal graphs, has been…

Data Structures and Algorithms · Computer Science 2024-07-19 Konstantinos Dogeas , Thomas Erlebach , Frank Kammer , Johannes Meintrup , William K. Moses