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Sorting is one of the most basic primitives in many algorithms and data analysis tasks. Comparison-based sorting algorithms, like quick-sort and merge-sort, are known to be optimal when the outcome of each comparison is error-free. However,…

Data Structures and Algorithms · Computer Science 2025-05-06 Ragesh Jaiswal , Amit Kumar , Jatin Yadav

QAC circuits are quantum circuits with one-qubit gates and Toffoli gates of arbitrary arity. QAC$^0$ circuits are QAC circuits of constant depth, and are quantum analogues of AC$^0$ circuits. We prove the following: $\bullet$ For all $d \ge…

Quantum Physics · Physics 2020-12-01 Gregory Rosenthal

We investigate the boundary between classical and quantum computational power. This work consists of two parts. First we develop new classical simulation algorithms that are centered on sampling methods. Using these techniques we generate…

Quantum Physics · Physics 2012-02-20 M. Van den Nest

This paper considers an optimization problem for a dynamical system whose evolution depends on a collection of binary decision variables. We develop scalable approximation algorithms with provable suboptimality bounds to provide…

Optimization and Control · Mathematics 2016-10-31 Insoon Yang , Samuel A. Burden , Ram Rajagopal , S. Shankar Sastry , Claire J. Tomlin

A line of work initiated by Fortnow in 1997 has proven model-independent time-space lower bounds for the $\mathsf{SAT}$ problem and related problems within the polynomial-time hierarchy. For example, for the $\mathsf{SAT}$ problem, the…

Computational Complexity · Computer Science 2021-02-01 Abhijit S. Mudigonda , R. Ryan Williams

Quantum circuits composed of CNOT and $R_z$ are fundamental building blocks of many quantum algorithms, so optimizing the synthesis of such quantum circuits is crucial. We address this problem from a theoretical perspective by studying the…

Quantum Physics · Physics 2025-09-15 Yixin Cao , Yiren Lu , Junhong Nie , Xiaoming Sun , Guojing Tian

The minimum-cost flow problem is a classic problem in combinatorial optimization with various applications. Several pseudo-polynomial, polynomial, and strongly polynomial algorithms have been developed in the past decades, and it seems that…

Data Structures and Algorithms · Computer Science 2015-09-16 Tobias Brunsch , Kamiel Cornelissen , Bodo Manthey , Heiko Röglin , Clemens Rösner

We present an algorithm for efficiently approximating of qubit unitaries over gate sets derived from totally definite quaternion algebras. It achieves $\varepsilon$-approximations using circuits of length $O(\log(1/\varepsilon))$, which is…

Quantum Physics · Physics 2015-10-16 Vadym Kliuchnikov , Alex Bocharov , Martin Roetteler , Jon Yard

Motivated by the desire to utilize a limited number of configurable optical switches by recent advances in Software Defined Networks (SDNs), we define an online problem which we call the Caching in Matchings problem. This problem has a…

Data Structures and Algorithms · Computer Science 2024-02-26 Yaniv Sadeh , Haim Kaplan

We study the problem of reaching agreement in a synchronous distributed system by $n$ autonomous parties, when the communication links from/to faulty parties can omit messages. The faulty parties are selected and controlled by an adaptive,…

Distributed, Parallel, and Cluster Computing · Computer Science 2024-05-27 Mohammad T. Hajiaghayi , Dariusz R. Kowalski , Jan Olkowski

Near term quantum computers with a high quantity (around 50) and quality (around 0.995 fidelity for two-qubit gates) of qubits will approximately sample from certain probability distributions beyond the capabilities of known classical…

Quantum Physics · Physics 2018-01-23 Sergio Boixo , Sergei V. Isakov , Vadim N. Smelyanskiy , Hartmut Neven

We give a novel procedure for approximating general single-qubit unitaries from a finite universal gate set by reducing the problem to a novel magnitude approximation problem, achieving an immediate improvement in sequence length by a…

Quantum Physics · Physics 2023-12-20 Vadym Kliuchnikov , Kristin Lauter , Romy Minko , Adam Paetznick , Christophe Petit

The problem of enumerating all connected induced subgraphs of a given order $k$ from a given graph arises in many practical applications: bioinformatics, information retrieval, processor design,to name a few. The upper bound on the number…

Data Structures and Algorithms · Computer Science 2023-03-16 Shanshan Wang , Chenglong Xiao , Emmanuel Casseau

We prove a Carbery-Wright style anti-concentration inequality for the unitary Haar measure, by showing that the probability of a polynomial in the entries of a random unitary falling into an $\varepsilon$ range is at most a polynomial in…

Quantum Physics · Physics 2025-12-01 Bill Fefferman , Soumik Ghosh , Wei Zhan

A crucial subroutine in quantum computing is to load the classical data of $N$ complex numbers into the amplitude of a superposed $n=\lceil \log_2N\rceil$-qubit state. It has been proven that any algorithm universally implementing this…

Quantum Physics · Physics 2021-08-13 Xiao-Ming Zhang , Man-Hong Yung , Xiao Yuan

Random quantum circuits have been utilized in the contexts of quantum supremacy demonstrations, variational quantum algorithms for chemistry and machine learning, and blackhole information. The ability of random circuits to approximate any…

Quantum Physics · Physics 2023-03-23 Minzhao Liu , Junyu Liu , Yuri Alexeev , Liang Jiang

We propose a first-order augmented Lagrangian algorithm (FALC) to solve the composite norm minimization problem min |sigma(F(X)-G)|_alpha + |C(X)- d|_beta subject to A(X)-b in Q; where sigma(X) denotes the vector of singular values of X,…

Optimization and Control · Mathematics 2012-08-07 Necdet Serhat Aybat , Garud Iyengar

One of the main challenges in building a quantum processor is to characterize the environmental noise. Noise characterization can be achieved by exploiting different techniques, such as randomization where several sequences of random…

Quantum Physics · Physics 2020-11-04 Elena Ferraro , Marco De Michielis

In this paper we consider parallelization for applications whose objective can be expressed as maximizing a non-monotone submodular function under a cardinality constraint. Our main result is an algorithm whose approximation is arbitrarily…

Data Structures and Algorithms · Computer Science 2018-07-31 Eric Balkanski , Adam Breuer , Yaron Singer

Initially developed for the min-knapsack problem, the knapsack cover inequalities are used in the current best relaxations for numerous combinatorial optimization problems of covering type. In spite of their widespread use, these…

Discrete Mathematics · Computer Science 2016-11-22 Abbas Bazzi , Samuel Fiorini , Sangxia Huang , Ola Svensson