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The Quantum Approximate Optimization Algorithm (QAOA) by Farhi et al. is a quantum computational framework for solving quantum or classical optimization tasks. Here, we explore using QAOA for Binary Linear Least Squares (BLLS); a problem…

Quantum Physics · Physics 2021-04-27 Ajinkya Borle , Vincent E. Elfving , Samuel J. Lomonaco

We show that almost all n-bit Boolean functions have bounded-error quantum query complexity at least n/2, up to lower-order terms. This improves over an earlier n/4 lower bound of Ambainis, and shows that van Dam's oracle interrogation is…

Quantum Physics · Physics 2012-08-07 Andris Ambainis , Arturs Backurs , Juris Smotrovs , Ronald de Wolf

Case-Based Reasoning (CBR) is an artificial intelligence approach to problem-solving with a good record of success. This article proposes using Quantum Computing to improve some of the key processes of CBR, such that a Quantum Case-Based…

Artificial Intelligence · Computer Science 2022-01-12 Parfait Atchade-Adelomou , Daniel Casado-Fauli , Elisabet Golobardes-Ribe , Xavier Vilasis-Cardona

We propose a quantum algorithm for closest pattern matching which allows us to search for as many distinct patterns as we wish in a given string (database), requiring a query function per symbol of the pattern alphabet. This represents a…

Quantum Physics · Physics 2007-05-23 P. Mateus , Y. Omar

The Quadratic Unconstrained Binary Optimization (QUBO) modeling and solution framework is a requirement for quantum and digital annealers. However optimality for QUBO problems of any practical size is extremely difficult to achieve. In…

Artificial Intelligence · Computer Science 2021-05-13 Amit Verma , Mark Lewis

In the search with wildcards problem [Ambainis, Montanaro, Quantum Inf.~Comput.'14], one's goal is to learn an unknown bit-string $x \in \{-1,1\}^n$. An algorithm may, at unit cost, test equality of any subset of the hidden string with a…

Quantum Physics · Physics 2025-11-07 Arjan Cornelissen , Nikhil S. Mande , Subhasree Patro , Nithish Raja , Swagato Sanyal

To implement arbitrary quantum circuits in architectures with restricted interactions, one may effectively simulate all-to-all connectivity by routing quantum information. We consider the entanglement dynamics and routing between two…

Quantum Information scrambling (QI-scrambling) is a pivotal area of inquiry within the study of quantum many-body systems. This research derives mathematical upper and lower bounds for the scrambling rate by applying the Maligranda…

Quantum Physics · Physics 2025-07-25 Ahmed Zahia , M. Y. Abd-Rabbou , Atta ur Rahman , Cong Feng Qiao

Quantum-inspired classical algorithms provide us with a new way to understand the computational power of quantum computers for practically-relevant problems, especially in machine learning. In the past several years, numerous efficient…

Quantum Physics · Physics 2025-01-15 Nikhil S. Mande , Changpeng Shao

Due to the expected disparity in quantum vs. classical clock speeds, quantum advantage for branch and bound algorithms is more likely achievable in settings involving large search trees and low operator evaluation costs. Therefore, in this…

Optimization and Control · Mathematics 2024-07-30 Thomas Häner , Kyle E. C. Booth , Sima E. Borujeni , Elton Yechao Zhu

The quantum guesswork quantifies the minimum number of queries needed to guess the state of a quantum ensemble if one is allowed to query only one state at a time. Previous approaches to the computation of the guesswork were based on…

Quantum Physics · Physics 2023-08-28 Michele Dall'Arno , Francesco Buscemi , Takeshi Koshiba

In this paper we prove a space lower bound of $n^{\Omega(k)}$ for non-deterministic (syntactic) read-once branching programs ({\sc nrobp}s) on functions expressible as {\sc cnf}s with treewidth at most $k$ of their primal graphs. This lower…

Computational Complexity · Computer Science 2015-07-28 Igor Razgon

This paper presents an enhancement to Grover's search algorithm for instances where the number of items (or the size of the search problem) $N$ is not a power of 2. By employing an efficient algorithm for the preparation of uniform quantum…

Quantum Physics · Physics 2025-06-06 Alok Shukla , Prakash Vedula

The Quantum Alternating Operator Ansatz (QAOA) represents a branch of quantum algorithms for solving combinatorial optimization problems. A specific variant, the Grover-Mixer Quantum Alternating Operator Ansatz (GM-QAOA), ensures uniform…

Quantum Physics · Physics 2024-05-27 Ningyi Xie , Jiahua Xu , Tiejin Chen , Xinwei Lee , Yoshiyuki Saito , Nobuyoshi Asai , Dongsheng Cai

The widely used quantum Cramer-Rao bound (QCRB) sets a lower bound for the mean square error of unbiased estimators in quantum parameter estimation, however, in general QCRB is only tight in the asymptotical limit. With a limited number of…

Quantum Physics · Physics 2016-09-07 Jing Liu , Haidong Yuan

The hybrid quantum-classical learning scheme provides a prominent way to achieve quantum advantages on near-term quantum devices. A concrete example towards this goal is the quantum neural network (QNN), which has been developed to…

Quantum Physics · Physics 2022-05-31 Yuxuan Du , Min-Hsiu Hsieh , Tongliang Liu , Dacheng Tao

Quantum networks will allow to implement communication tasks beyond the reach of their classical counterparts. A pressing and necessary issue for the design of quantum network protocols is the quantification of the rates at which these…

Quantum Physics · Physics 2020-04-22 Stefan Bäuml , Koji Azuma , Go Kato , David Elkouss

We study the unsorted database search problem with items $N$ from the viewpoint of unitary discrimination. Instead of considering the famous $O(\sqrt{N})$ Grover's the bounded-error algorithm for the original problem, we seek for the…

Quantum Physics · Physics 2009-11-13 Xiaodi Wu , Runyao Duan

The laws of quantum mechanics place fundamental limits on the accuracy of measurements and therefore on the estimation of unknown parameters of a quantum system. In this work, we prove lower bounds on the size of confidence regions reported…

Quantum Physics · Physics 2014-12-23 Michael Walter , Joseph M. Renes

The barren plateau phenomenon is one of the main obstacles to implementing variational quantum algorithms in the current generation of quantum processors. Here, we introduce a method capable of avoiding the barren plateau phenomenon in the…