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Quantum computing provides a powerful framework for tackling computational problems that are classically intractable. The goal of this paper is to explore the use of quantum computers for solving relevant problems in systems and control…

Systems and Control · Electrical Eng. & Systems 2025-12-23 Jan Schneider , Julian Berberich

Quantum computations promise the ability to solve problems intractable in the classical setting. Restricting the types of computations considered often allows to establish a provable theoretical advantage by quantum computations, and later…

Quantum Physics · Physics 2021-11-19 Dmitri Maslov , Jin-Sung Kim , Sergey Bravyi , Theodore J. Yoder , Sarah Sheldon

In this paper, we study quantum algorithms of matrix multiplication from the viewpoint of inputting quantum/classical data to outputting quantum/classical data. The main target is trying to overcome the input and output problem, which are…

Quantum Physics · Physics 2018-07-31 Changpeng Shao

We investigate the power of quantum computers when they are required to return an answer that is guaranteed to be correct after a time that is upper-bounded by a polynomial in the worst case. We show that a natural generalization of Simon's…

Quantum Physics · Physics 2017-01-04 Gilles Brassard , Peter Hoyer

Many claims of computational advantages have been made for quantum computing over classical, but they have not been demonstrated for practical problems. Here, we present algorithms for solving time-dependent PDEs, with particular reference…

Quantum Physics · Physics 2025-06-17 Sachin S. Bharadwaj , Katepalli R. Sreenivasan

We develop an extension of recently developed methods for obtaining time-space tradeoff lower bounds for problems of learning from random test samples to handle the situation where the space of tests is signficantly smaller than the space…

Machine Learning · Computer Science 2017-08-10 Paul Beame , Shayan Oveis Gharan , Xin Yang

Obeying constraints imposed by classical physics, we give optimal fine-grained algorithms for matrix multiplication and problems involving graphs and mazes, where all calculations are done in 3-dimensional space. We assume that whatever the…

Data Structures and Algorithms · Computer Science 2024-12-20 Quentin F. Stout

We consider the problem of preprocessing an $n\times n$ matrix $\mathbf{M}$, and supporting queries that, for any vector $v$, returns the matrix-vector product $\mathbf{M} v$. This problem has been extensively studied in both theory and…

Data Structures and Algorithms · Computer Science 2026-02-10 Emile Anand , Jan van den Brand , Rose McCarty

Since Harrow, Hassidim, and Lloyd (2009) showed that a system of linear equations with $N$ variables and condition number $\kappa$ can be solved on a quantum computer in $\operatorname{poly}(\log(N), \kappa)$ time, exponentially faster than…

Quantum Physics · Physics 2024-07-16 Qisheng Wang , Zhicheng Zhang

Running quantum algorithms often involves implementing complex quantum circuits with such a large number of multi-qubit gates that the challenge of tackling practical applications appears daunting. To date, no experiments have successfully…

In this work, we establish the first separation between computation with bounded and unbounded space, for problems with short outputs (i.e., working memory can be exponentially larger than output size), both in the classical and the quantum…

Computational Complexity · Computer Science 2026-04-07 Zihan Hao , Zikuan Huang , Qipeng Liu

We describe two algorithms for multiplying n x n matrices using time and energy n^2 polylog(n) under basic models of classical physics. The first algorithm is for multiplying integer-valued matrices, and the second, quite different…

Computational Complexity · Computer Science 2023-12-14 Gregory Valiant

We present a quantum algorithm that verifies a product of two n*n matrices over any field with bounded error in worst-case time n^{5/3} and expected time n^{5/3} / min(w,sqrt(n))^{1/3}, where w is the number of wrong entries. This improves…

Quantum Physics · Physics 2007-05-23 Harry Buhrman , Robert Spalek

This work explores fundamental modeling and algorithmic issues arising in the well-established MapReduce framework. First, we formally specify a computational model for MapReduce which captures the functional flavor of the paradigm by…

Data Structures and Algorithms · Computer Science 2013-06-13 Andrea Pietracaprina , Geppino Pucci , Matteo Riondato , Francesco Silvestri , Eli Upfal

A tight lower bound for required I/O when computing an ordinary matrix-matrix multiplication on a processor with two layers of memory is established. Prior work obtained weaker lower bounds by reasoning about the number of segments needed…

Computational Complexity · Computer Science 2019-02-07 Tyler Michael Smith , Bradley Lowery , Julien Langou , Robert A. van de Geijn

Branching programs are quite popular for studying time-space lower bounds. Bera et al. recently introduced the model of generalized quantum branching program aka. GQBP that generalized two earlier models of quantum branching programs. In…

Quantum Physics · Physics 2024-10-08 Debajyoti Bera , Tharrmashastha SAPV

Multiple Tensor-Times-Matrix (Multi-TTM) is a key computation in algorithms for computing and operating with the Tucker tensor decomposition, which is frequently used in multidimensional data analysis. We establish communication lower…

Distributed, Parallel, and Cluster Computing · Computer Science 2023-02-03 Hussam Al Daas , Grey Ballard , Laura Grigori , Suraj Kumar , Kathryn Rouse

A fertile area of recent research has demonstrated concrete polynomial time lower bounds for solving natural hard problems on restricted computational models. Among these problems are Satisfiability, Vertex Cover, Hamilton Path, Mod6-SAT,…

Computational Complexity · Computer Science 2010-02-03 Ryan Williams

We give a new version of the adversary method for proving lower bounds on quantum query algorithms. The new method is based on analyzing the eigenspace structure of the problem at hand. We use it to prove a new and optimal strong direct…

Quantum Physics · Physics 2007-05-23 Andris Ambainis , Robert Spalek , Ronald de Wolf

For a decision problem from coding theory, we prove a quadratic expected time-space tradeoff of the form $\eT\eS=\Omega(\tfrac{n^2}{q})$ for $q$-way deterministic decision branching programs, where $q\geq 2$. Here $\eT$ is the expected…

Computational Complexity · Computer Science 2020-01-21 Nandakishore Santhi , Alexander Vardy