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We investigate the quantum equation of motion (qEOM), a hybrid quantum-classical algorithm for computing excitation properties of a fermionic many-body system, with a particular emphasis on the strong-coupling regime. The method is designed…

Nuclear Theory · Physics 2023-09-20 Manqoba Q. Hlatshwayo , John Novak , Elena Litvinova

The usual semiclassical approximation for atom-field dynamics consists in substituting the field operators by complex numbers related to the (supposedly large enough) intensity of the field. We show that a semiclassical evolution for…

Quantum Physics · Physics 2015-05-13 R. Rossi , K. M. Fonseca , Romero M. C. Nemes

We propose a variational approach to explore quasiparticle excitations in interacting quantum many-body systems, motivated by the potential in leveraging near-term noisy intermediate scale quantum devices for quantum state preparation. By…

Quantum Physics · Physics 2025-02-12 Rimika Jaiswal , Izabella Lovas , Leon Balents

In this article we investigate driven dissipative quantum dynamics of an ensemble of two-level systems given by a Markovian master equation with collective and non-collective dissipators. Exploiting the permutation symmetry in our model, we…

Quantum Physics · Physics 2021-02-03 Konrad Merkel , Valentin Link , Kimmo Luoma , Walter T. Strunz

We investigate the fully quantum evolution of the population imbalance in a perfectly symmetric Bose-Josephson junction modeled by a two-mode Bose-Hubbard Hamiltonian, focusing on the validity of macroscopic quantum self-trapping beyond the…

Quantum Gases · Physics 2026-04-14 Andrea Bardin , Anna Minguzzi , Luca Salasnich

State-space smoothing has found many applications in science and engineering. Under linear and Gaussian assumptions, smoothed estimates can be obtained using efficient recursions, for example Rauch-Tung-Striebel and Mayne-Fraser algorithms.…

Optimization and Control · Mathematics 2016-09-27 A. Y. Aravkin , J. V. Burke , L. Ljung , A. Lozano , G. Pillonetto

We examine the medium time quantum dynamics and population equilibration of two, three and four-well Bose-Hubbard models using stochastic integration in the truncated Wigner phase-space representation. We find that all three systems will…

Quantum Gases · Physics 2015-05-30 C. V. Chianca , M. K. Olsen

To analyze quantum many-body Hamiltonians, recently, machine learning techniques have been shown to be quite useful and powerful. However, the applicability of such machine learning solvers is still limited. Here, we propose schemes that…

Strongly Correlated Electrons · Physics 2020-04-17 Yusuke Nomura

This paper proposes a novel approach for learning a data-driven quadratic manifold from high-dimensional data, then employing this quadratic manifold to derive efficient physics-based reduced-order models. The key ingredient of the approach…

Numerical Analysis · Mathematics 2022-12-29 Rudy Geelen , Stephen Wright , Karen Willcox

An approach to the quantum-classical mechanics of phase space dependent operators, which has been proposed recently, is remodeled as a formalism for wave fields. Such wave fields obey a system of coupled non-linear equations that can be…

Quantum Physics · Physics 2007-05-23 Alessandro Sergi

While the treatment of chemically relevant systems containing hundreds or even thousands of electrons remains beyond the reach of quantum devices, the development of quantum-classical hybrid algorithms to resolve electronic correlation…

In the previous paper [J. R. Mannouch and J. O. Richardson, J.~Chem.~Phys.~xxx, xxxxx (xxxx)] we derived a new partially linearized mapping-based classical-trajectory technique, called spin-PLDM. This method describes the dynamics…

Chemical Physics · Physics 2021-02-03 J. R. Mannouch , J. O. Richardson

Unbiased stochastic sampling of the one- and two-body reduced density matrices is achieved in full configuration interaction quantum Monte Carlo with the introduction of a second, "replica" ensemble of walkers, whose population evolves in…

Computational Physics · Physics 2015-09-02 Robert E. Thomas , Daniel Opalka , Catherine Overy , Peter J. Knowles , Ali Alavi , George H. Booth

Preparing algebraically correlated ground states of quantum many-body systems is an important, yet challenging task for quantum simulation. We introduce a protocol that employs local projective measurements and unitary feedback for…

Quantum Physics · Physics 2026-03-12 Johannes Feldmeier , Yu-Jie Liu , Mikhail D. Lukin , Soonwon Choi

We introduce a novel methodology for simulating the excited-state dynamics of extensive molecular aggregates in the framework of the long-range corrected time-dependent density-functional tight-binding fragment molecular orbital method…

Chemical Physics · Physics 2024-04-23 Richard Einsele , Roland Mitrić

We put forward a Monte Carlo algorithm that samples the Euclidean time operator growth dynamics at infinite temperature. Crucially, our approach is free from the numerical sign problem for a broad family of quantum many-body spin systems,…

Strongly Correlated Electrons · Physics 2024-11-26 Ayush De , Umberto Borla , Xiangyu Cao , Snir Gazit

Probing correlated states of many-body systems is one of the central tasks for quantum simulators and processors. A promising approach to state preparation is to realize desired correlated states as steady states of engineered dissipative…

Quantum Physics · Physics 2025-02-05 Jerome Lloyd , Alexios Michailidis , Xiao Mi , Vadim Smelyanskiy , Dmitry A. Abanin

The models in statistical physics such as an Ising model offer a convenient way to characterize stationary activity of neural populations. Such stationary activity of neurons may be expected for recordings from in vitro slices or…

Neurons and Cognition · Quantitative Biology 2017-05-05 Christian Donner , Klaus Obermayer , Hideaki Shimazaki

While quantum algorithms for simulation exhibit better asymptotic scaling than their classical counterparts, they currently cannot be implemented on real-world devices. Instead, chemists and computer scientists rely on costly classical…

Quantum Physics · Physics 2022-06-03 Christopher Kang , Nicholas P. Bauman , Sriram Krishnamoorthy , Karol Kowalski

In this paper, we formally demonstrate that the non-equilibrium density matrix developed by Hershfield for the steady state has the form of a McLennan-Zubarev non-equilibrium ensemble. The correction term in this pseudo equilibrium…

Statistical Mechanics · Physics 2014-02-26 H. Ness