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I investigate whether it would technologically and economically make sense to build database search engines based on Grover's quantum search algorithm. The answer is not fully conclusive but in my judgement rather negative.

Quantum Physics · Physics 2009-10-31 Christof Zalka

Recently, Andreas de Vries proposed a quantum algorithm that would find an element in an unsorted database exponentially faster than Grover's algorithm. We show that de Vries' algorithm does not work as intended and does not give any clue…

Quantum Physics · Physics 2007-05-23 L. A. B. Kowada , C. M. H. de Figueiredo , R. Portugal , C. C. Lavor

Sorting is a fundamental computational process, which facilitates subsequent searching of a database. It can be thought of as factorisation of the search process. The location of a desired item in a sorted database can be found by classical…

Quantum Physics · Physics 2009-11-06 Apoorva Patel

Grover's quantum search algorithm promises a quadratic speedup for unstructured search over its classical counterpart. But this advantage is affected by noise acting on the search space. Here, we show that a quantum switch can act as a…

Quantum Physics · Physics 2025-05-13 Suryansh Srivastava , Arun K. Pati , Samyadeb Bhattacharya , Indranil Chakrabarty

In this paper, we extend a previously presented Grover-based heuristic to tackle general combinatorial optimization problems with linear constraints. We further describe the introduced method as a framework that enables performance…

Quantum Physics · Physics 2025-12-08 Sören Wilkening , Timo Ziegler , Maximilian Hess

In this paper, we study decoherence on Grover's quantum searching algorithm using a perturbative method. We assume that each two-state system (qubit) suffers \sigma_{z} error with probability p (0\leq p\leq 1) independently at every step in…

Quantum Physics · Physics 2010-09-03 Hiroo Azuma

The landmark Grover algorithm for amplitude amplification serves as an essential subroutine in various type of quantum algorithms, with guaranteed quantum speedup in query complexity. However, there have been no proposal to realize the…

Quantum Physics · Physics 2022-03-28 Hiroyuki Tezuka , Kouhei Nakaji , Takahiko Satoh , Naoki Yamamoto

Grover's algorithm accelerates unstructured database search quadratically compared to classical algorithms. In the NISQ era, distributed quantum computing can decrease circuit depth and reduce noise. In this paper, an algorithm for…

Quantum Physics · Physics 2026-04-16 Huaijing Huang , Daowen Qiu , Ximing Hua , Xinyu Chen

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

In the multitarget Grover algorithm, we are given an unstructured N-element list of objects S_i containing a T-element subset tau and function f, called an oracle, such that f(S_i)=1 if S_i is in tau, otherwise f(S_i) = 0. By using quantum…

Quantum Physics · Physics 2013-05-29 Keith Kastella , Richard Freeling

Imagine a phone directory containing N names arranged in completely random order. In order to find someone's phone number with a 50% probability, any classical algorithm (whether deterministic or probabilistic) will need to look at a…

Quantum Physics · Physics 2008-02-03 Lov K. Grover

The study of quantum computation has been motivated by the hope of finding efficient quantum algorithms for solving classically hard problems. In this context, quantum algorithms by local adiabatic evolution have been shown to solve an…

Quantum Physics · Physics 2009-11-10 Jérémie Roland , Nicolas J. Cerf

We discuss quantum algorithms that calculate numerical integrals and descriptive statistics of stochastic processes. With either of two distinct approaches, one obtains an exponential speed increase in comparison to the fastest known…

Quantum Physics · Physics 2007-05-23 Daniel S. Abrams , Colin P. Williams

Some of the secret sharing schemes having unique quantum features like parallelism and entanglement are supposed to be relatively secure. Different schemes proposed by various researchers over the years have features which could be specific…

Quantum Physics · Physics 2007-07-10 Arti Chamoli , C. M. Bhandari

In this paper we propose an approach to prepare GHZ states of an arbitrary multi-particle system in terms of Grover's fast quantum searching algorithm. This approach can be regarded as an extension of the Grover's algorithm to find one or…

Quantum Physics · Physics 2015-06-26 Hao-Sheng Zeng , Le-Man Kuang

The search task is one of the most difficult when it comes to execution speed, and reducing the latter is important both when working with large data and with small samples, if they need to be processed frequently and in a limited time.…

Quantum Physics · Physics 2025-04-24 Karina Zakharova

There exist quantum algorithms that are more efficient than their classical counterparts; such algorithms were invented by Shor in 1994 and then Grover in 1996. A lack of invention since Grover's algorithm has been commonly attributed to…

Quantum Physics · Physics 2007-08-27 Adrian Gepp , Phil Stocks

It has been shown in recent years that quantum information has a topological nature (\cite{AC}, \cite{Co}, \cite{Co2}). In \cite{V}, Vicary undergoes the study of quantum algorithms using this new topological approach. The advantage of this…

Quantum Physics · Physics 2014-05-20 Ali Nabi Duman

Grover's algorithm is one of the most famous algorithms which explicitly demonstrates how the quantum nature can be utilized to accelerate the searching process. In this work, Grover's quantum search problem is mapped to a time-optimal…

Quantum Physics · Physics 2019-08-28 Chungwei Lin , Yebin Wang , Grigory Kolesov , Uroš Kalabić

Database search has wide applications and is used as a subroutine in many important algorithms. We shall consider a database with one target item. Quantum algorithm finds the target item in a database faster than any classical algorithm. It…

Quantum Physics · Physics 2009-11-13 Vladimir Korepin , Ying Xu