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We consider a classical scheduling problem on $m$ identical machines. For an arbitrary constant $q>1$, the aim is to assign jobs to machines such that $\sum_{i=1}^m C_i^q$ is minimized, where $C_i$ is the total processing time of jobs…

Computational Complexity · Computer Science 2021-07-14 Lin Chen , Liangde Tao , José Verschae

We show that one can approximate the least fixed point solution for a multivariate system of monotone probabilistic polynomial equations in time polynomial in both the encoding size of the system of equations and in log(1/\epsilon), where…

Computational Complexity · Computer Science 2013-02-21 Kousha Etessami , Alistair Stewart , Mihalis Yannakakis

The celebrated result of Kabanets and Impagliazzo (Computational Complexity, 2004) showed that PIT algorithms imply circuit lower bounds, and vice versa. Since then it has been a major challenge to understand the precise connections between…

Computational Complexity · Computer Science 2025-08-19 Robert Andrews , Deepanshu Kush , Roei Tell

In this paper, we obtain a number of new simple pseudo-polynomial time algorithms on the well-known knapsack problem, focusing on the running time dependency on the number of items $n$, the maximum item weight $w_\mathrm{max}$, and the…

Data Structures and Algorithms · Computer Science 2024-01-30 Qizheng He , Zhean Xu

An area law is proved for the Renyi entanglement entropy of possibly degenerate ground states in one-dimensional gapped quantum systems. Suppose in a chain of $n$ spins the ground states of a local Hamiltonian with energy gap $\epsilon$ are…

Strongly Correlated Electrons · Physics 2015-01-08 Yichen Huang

A method is presented in which the ground-state subspace is projected out of a Hamiltonian representation. As a result of this projection, an effective Hamiltonian is constructed where its ground-state coincides with an excited-state of the…

Quantum Physics · Physics 2023-08-14 P. Jouzdani , S. Bringuier , M. Kostuk

Time-driven quantum systems are important in many different fields of physics like cold atoms, solid state, optics, etc. Many of their properties are encoded in the time evolution operator which is calculated by using a time-ordered product…

Polynomially-large ground-state energy gaps are rare in many-body quantum systems, but useful for adiabatic quantum computing. We show analytically that the gap is generically polynomially-large for quadratic fermionic Hamiltonians. We then…

Quantum Physics · Physics 2013-05-29 Michael J. O'Hara , Dianne P. O'Leary

This paper is concerned with linear parameter-dependent systems and considers the notion uniform ensemble reachability. The focus of this work is on constructive methods to compute suitable parameter-independent open-loop inputs for such…

Optimization and Control · Mathematics 2023-06-16 Michael Schönlein

Finding the ground state of a quantum many-body system is a fundamental problem in quantum physics. In this work, we give a classical machine learning (ML) algorithm for predicting ground state properties with an inductive bias encoding…

Quantum Physics · Physics 2024-10-18 Laura Lewis , Hsin-Yuan Huang , Viet T. Tran , Sebastian Lehner , Richard Kueng , John Preskill

We study polynomial time algorithms for estimating the mean of a heavy-tailed multivariate random vector. We assume only that the random vector $X$ has finite mean and covariance. In this setting, the radius of confidence intervals achieved…

Statistics Theory · Mathematics 2019-06-05 Samuel B. Hopkins

We present an efficient quantum algorithm for simulating the evolution of a sparse Hamiltonian H for a given time t in terms of a procedure for computing the matrix entries of H. In particular, when H acts on n qubits, has at most a…

Quantum Physics · Physics 2007-05-23 Dominic W. Berry , Graeme Ahokas , Richard Cleve , Barry C. Sanders

The well-known algorithm for quantum phase estimation requires that the considered unitary is available as a conditional transformation depending on the quantum state of an ancilla register. We present an algorithm converting an unknown…

Quantum Physics · Physics 2007-05-23 Dominik Janzing

An important objective in scheduling literature is to minimize the sum of weighted flow times. We are given a set of jobs where each job is characterized by a release time, a processing time, and a weight. Our goal is to find a preemptive…

Data Structures and Algorithms · Computer Science 2022-08-08 Alexander Armbruster , Lars Rohwedder , Andreas Wiese

We present a quantum algorithm to achieve higher-order transformations of Hamiltonian dynamics. Namely, the algorithm takes as input a finite number of queries to a black-box seed Hamiltonian dynamics to simulate a desired Hamiltonian. Our…

Quantum Physics · Physics 2024-06-13 Tatsuki Odake , Hlér Kristjánsson , Akihito Soeda , Mio Murao

Imaginary-time evolution is fundamental for analyzing quantum many-body systems, yet classical simulation requires exponentially growing resources in both system size and evolution time. While quantum approaches reduce the system-size…

Quantum Physics · Physics 2025-12-12 Lei Zhang , Jizhe Lai , Xian Wu , Xin Wang

We give a quasi-polynomial time classical algorithm for estimating the ground state energy and for computing low energy states of quantum impurity models. Such models describe a bath of free fermions coupled to a small interacting subsystem…

Quantum Physics · Physics 2018-10-23 Sergey Bravyi , David Gosset

Manipulating Hamiltonians governing physical systems has found a broad range of applications, from quantum chemistry to semiconductor design. In this work, we provide a new way of manipulating Hamiltonians, by transforming their eigenvalues…

Quantum Physics · Physics 2025-04-30 Tatsuki Odake , Hlér Kristjánsson , Philip Taranto , Mio Murao

By using the properties of orthogonal polynomials, we present an exact unitary transformation that maps the Hamiltonian of a quantum system coupled linearly to a continuum of bosonic or fermionic modes to a Hamiltonian that describes a…

Quantum Physics · Physics 2010-10-04 Alex W. Chin , Ángel Rivas , Susana F. Huelga , Martin B. Plenio

We introduce a new concept of approximation applicable to decision problems and functions, inspired by Bayesian probability. From the perspective of a Bayesian reasoner with limited computational resources, the answer to a problem that…

Computational Complexity · Computer Science 2025-06-27 Vanessa Kosoy , Alexander Appel