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Related papers: The effect of unitary noise on Grover's quantum se…

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Grover's algorithm for quantum searching of a database is generalized to deal with arbitrary initial amplitude distributions. First order linear difference equations are found for the time evolution of the amplitudes of the r marked and N-r…

Quantum Physics · Physics 2016-09-08 David Biron , Ofer Biham , Eli Biham , Markus Grassl , Daniel A. Lidar

Grover's quantum algorithm can find a marked item from an unstructured database faster than any classical algorithm, and hence it has been used for several applications such as cryptanalysis and optimization. When there exist multiple…

Quantum Physics · Physics 2025-07-02 Kota Tani , Shunji Tsuchiya , Seiichiro Tani , Yuki Takeuchi

$ $In its usual form, Grover's quantum search algorithm uses $O(\sqrt{N})$ queries and $O(\sqrt{N} \log N)$ other elementary gates to find a solution in an $N$-bit database. Grover in 2002 showed how to reduce the number of other gates to…

Quantum Physics · Physics 2016-10-24 Srinivasan Arunachalam , Ronald de Wolf

An algebraic analysis of Grover's quantum search algorithm is presented for the case in which the initial state is an arbitrary pure quantum state of n qubits. This approach reveals the geometrical structure of the quantum search process,…

Quantum Physics · Physics 2009-11-11 D. Shapira , Y. Shimoni , O. Biham

The variational quantum imaginary time evolution algorithm is efficient in finding the ground state of a quantum Hamiltonian. This algorithm involves solving a system of linear equations in a classical computer and the solution is then used…

Quantum Physics · Physics 2024-05-10 Gaurav Saxena , Ahmed Shalabi , Thi Ha Kyaw

Grover's algorithm solves the unstructured search problem. Grover's algorithm can find the target state with certainty only if searching one out of four. Designing the deterministic search algorithm can avoid any repetition of the…

Quantum Physics · Physics 2025-01-14 Zhen Wang , Kun Zhang , Vladimir Korepin

Many quantum algorithms rely on the measurement of complex quantum amplitudes. Standard approaches to obtain the phase information, such as the Hadamard test, give rise to large overheads due to the need for global controlled-unitary…

Quantum Physics · Physics 2024-05-29 Yilun Yang , Arthur Christianen , Mari Carmen Bañuls , Dominik S. Wild , J. Ignacio Cirac

A recently proposed variational quantum algorithm has expanded the horizon of variational quantum computing to nonlinear physics and fluid dynamics. In this work, we probe the ability of such approaches to capture the ground state of the…

Quantum Physics · Physics 2025-07-15 Muhammad Umer , Eleftherios Mastorakis , Sofia Evangelou , Dimitris G. Angelakis

Crosstalk and several sources of operational interference are invisible when qubit or a gate is calibrated or benchmarked in isolation. These are unlocked during the execution of full quantum circuit applying entangling gates to several…

Quantum Physics · Physics 2022-03-02 Muhammad Ahsan

Since the final quantum state in the Grover search algorithm is the normalized marked quantum state from the Gram-Schmidt process, Abrams and Lloyd [1] has shown that we can generate this vector by using a non-unitary gate. Following their…

Quantum Physics · Physics 2025-08-22 Ammar Daskin

Understanding and mitigating noise in quantum systems is a fundamental challenge in achieving scalable and fault-tolerant quantum computation. Error modeling for quantum systems can be formulated in many ways, some of which are very…

In general, a quantum algorithm wants to avoid decoherence or perturbation, since such factors may cause errors in the algorithm. In this letter, we will supply the answer to the interesting question: can the factors seemingly harmful to a…

Quantum Physics · Physics 2007-05-23 Joonwoo Bae , Younghun Kwon

Quantum noise is a central challenge in quantum computing across many applications. Extensive work has examined how qubits couple to their environment, leading to decoherence and relaxation, which is irreversible. Current studies focus on…

Quantum Physics · Physics 2026-04-30 Yunos El Kaderi , Andreas Honecker , Iryna Andriyanova

We study some discrete symmetries of unbiased (Hadamard) and biased quantum walk on a line, which are shown to hold even when the quantum walker is subjected to environmental effects. The noise models considered in order to account for…

Quantum Physics · Physics 2009-11-13 C. M. Chandrashekar , R. Srikanth , Subhashish Banerjee

Overcoming the influence of noise and imperfections in quantum devices is one of the main challenges for viable quantum applications. In this article, we present different protocols, which we denote as "superposed quantum error mitigation",…

Grover's quantum search algorithm provides a quadratic speedup over the classical one. The computational complexity is based on the number of queries to the oracle. However, depth is a more modern metric for noisy intermediate-scale quantum…

Quantum Physics · Physics 2020-03-31 Kun Zhang , Vladimir E. Korepin

In this paper we present a novel quantum algorithm, namely the quantum grid search algorithm, to solve a special search problem. Suppose $ k $ non-empty buckets are given, such that each bucket contains some marked and some unmarked items.…

Quantum Physics · Physics 2019-09-11 Alok Shukla , Prakash Vedula

For the unsorted database quantum search with the unknown fraction $\lambda$ of target items, there are mainly two kinds of methods, i.e., fixed-point or trail-and-error. (i) In terms of the fixed-point method, Yoder et al. [Phys. Rev.…

Quantum Physics · Physics 2019-12-05 Tan Li , Shuo Zhang , Xiang-Qun Fu , Xiang Wang , Yang Wang , Jie Lin , Wan-Su Bao

Quantum noise is conventionally viewed as a fundamental obstacle in near-term quantum computing, motivating extensive error correction and mitigation strategies. We present numerical evidence that challenges this consensus. Through…

Quantum Physics · Physics 2026-01-21 Linghua Zhu , Yulong Dong , Ziyu Zhang , Xiaosong Li

Overcoming the influence of noise and imperfections is a major challenge in quantum computing. Here, we present an approach based on applying a desired unitary computation in superposition between the system of interest and some auxiliary…

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