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We analyze the efficiency of quantum simulations of fermionic and bosonic models in trapped ions. In particular, we study the optimal time of entangling gates and the required number of total elementary gates. Furthermore, we exemplify…

Quantum Physics · Physics 2014-06-19 L. Lamata , A. Mezzacapo , J. Casanova , E. Solano

Many interesting physical theories have analytic classical actions. We show how Feynman's path integral may be defined non-perturbatively, for such theories, without a Wick rotation to imaginary time. We start by introducing a class of…

High Energy Physics - Theory · Physics 2023-05-17 Job Feldbrugge , Neil Turok

Portfolio optimization plays a central role in finance to obtain optimal portfolio allocations that aim to achieve certain investment goals. Over the years, many works have investigated different variants of portfolio optimization.…

Quantum Physics · Physics 2023-02-01 Debbie Lim , Patrick Rebentrost

We propose a neural-network variational quantum algorithm to simulate the time evolution of quantum many-body systems. Based on a modified restricted Boltzmann machine (RBM) wavefunction ansatz, the proposed algorithm can be efficiently…

Quantum Physics · Physics 2021-05-12 Chee-Kong Lee , Pranay Patil , Shengyu Zhang , Chang-Yu Hsieh

We investigate the simulation of fermionic systems on a quantum computer. We show in detail how quantum computers avoid the dynamical sign problem present in classical simulations of these systems, therefore reducing a problem believed to…

Condensed Matter · Physics 2009-02-05 G. Ortiz , J. E. Gubernatis , E. Knill , R. Laflamme

The development of powerful numerical techniques has drastically improved our understanding of quantum matter out of equilibrium. Inspired by recent progress in the area of noisy intermediate-scale quantum devices, this paper highlights…

Quantum Physics · Physics 2024-04-01 Jonas Richter

While thousands of experimental physicists and chemists are currently trying to build scalable quantum computers, it appears that simulation of quantum computation will be at least as critical as circuit simulation in classical VLSI design.…

Quantum Physics · Physics 2007-05-23 George F. Viamontes , Manoj Rajagopalan , Igor L. Markov , John P. Hayes

Non-Markovianity may significantly speed up quantum dynamics when the system interacts strongly with an infinite large reservoir, of which the coupling spectrum should be fine-tuned. The potential benefits are evident in many dynamics…

Quantum Physics · Physics 2022-02-07 Xiangyi Meng , Yang Li , Jian-Wei Zhang , Hong Guo , H. Eugene Stanley

Despite extensive research efforts, few quantum algorithms for classical optimization demonstrate realizable quantum advantage. The utility of many quantum algorithms is limited by high requisite circuit depth and nonconvex optimization…

Quantum Physics · Physics 2022-01-27 Taylor L. Patti , Jean Kossaifi , Anima Anandkumar , Susanne F. Yelin

We present an implementation of Grover's algorithm in the framework of Feynman's cursor model of a quantum computer. The cursor degrees of freedom act as a quantum clocking mechanism, and allow Grover's algorithm to be performed using a…

Quantum Physics · Physics 2007-05-23 Diego de Falco , Dario Tamascelli

The model of open quantum systems is adopted to describe the non-local dynamical behaviour of qubits processed by entangling gates. The analysis gets to the conclusion that a distinction between evaluation steps and task-oriented computing…

Quantum Physics · Physics 2015-12-24 Stefano Bonzio , Paola Verrucchi

An $n$-qubit quantum circuit is said to be peaked if it has an output probability that is at least inverse-polynomially large as a function of $n$. We describe a classical algorithm with quasipolynomial runtime $n^{O(\log{n})}$ that…

Quantum Physics · Physics 2023-09-18 Sergey Bravyi , David Gosset , Yinchen Liu

We describe an algorithm that computes the ground state energy and correlation functions for 2-local Hamiltonians in which interactions between qubits are weak compared to single-qubit terms. The running time of the algorithm is polynomial…

Quantum Physics · Physics 2009-11-13 Sergey Bravyi , David DiVincenzo , Daniel Loss

We introduce a new discrete-time variational principle inspired by the quantum clock originally proposed by Feynman, and use it to write down quantum evolution as a ground state eigenvalue problem. The construction allows one to apply…

Quantum Physics · Physics 2014-03-05 Jarrod R. McClean , John A. Parkhill , Alán Aspuru-Guzik

The Vlasov-Maxwell system of equations, which describes classical plasma physics, is extremely challenging to solve, even by numerical simulation on powerful computers. By linearizing and assuming a Maxwellian background distribution…

Quantum Physics · Physics 2019-12-19 Alexander Engel , Graeme Smith , Scott E. Parker

We introduce a framework for the formal specification and verification of quantum circuits based on the Feynman path integral. Our formalism, built around exponential sums of polynomial functions, provides a structured and natural way of…

Quantum Physics · Physics 2019-01-30 Matthew Amy

For a quantum system undergoing non-Markovian open quantum dynamics, we demonstrate a tomography algorithm based on multi-time measurements of the system, which reconstructs a minimal environment coupled to the system, such that the system…

Quantum Physics · Physics 2022-08-31 Chu Guo

This paper introduces a novel method for approximating the dynamics of a large autonomous system projected onto a fixed subspace. The core contribution is a novel recursive algorithm to construct an effective time-dependent generator that…

Quantum Physics · Physics 2025-10-24 Tommaso Grigoletto

Digital quantum simulation uses the capabilities of quantum computers to determine the dynamics of quantum systems, which are beyond the computability of modern classical computers. A notoriously challenging task in this field is the…

Quantum Physics · Physics 2021-04-19 Benedikt Fauseweh , Jian-Xin Zhu

Quantum computers have the potential to efficiently solve a system of nonlinear ordinary differential equations (ODEs), which play a crucial role in various industries and scientific fields. However, it remains unclear which system of…

Quantum Physics · Physics 2025-04-07 Yu Tanaka , Keisuke Fujii