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We present a new approach to compute low lying eigenvalues and corresponding eigenvectors for strongly correlated many-body systems. The method was inspired by the so-called Automated Multilevel Sub-structuring Method (AMLS). Originally, it…

Computational Physics · Physics 2010-04-28 Ralf Gamillscheg , Gundolf Haase , Wolfgang von der Linden

Quantum many-body systems pose a formidable computational challenge due to the exponential growth of their Hilbert space. While machine learning (ML) has shown promise as an alternative paradigm, most applications remain at the…

Disordered Systems and Neural Networks · Physics 2026-02-03 Yilun Gao , Alberto Rodríguez , Rudolf A. Römer

For a wide class of Hamiltonians, a novel method to obtain lower and upper bounds for the lowest energy is presented. Unlike perturbative or variational techniques, this method does not involve the computation of any integral (a…

Quantum Physics · Physics 2009-11-10 Amaury Mouchet

State preparation is of fundamental importance in quantum physics, which can be realized by constructing the quantum circuit as a unitary that transforms the initial state to the target, or implementing a quantum control protocol to evolve…

Quantum Physics · Physics 2021-11-23 Ying Lu , Yue-Min Li , Peng-Fei Zhou , Shi-Ju Ran

Determining ground state energies of quantum systems by hybrid classical/quantum methods has emerged as a promising candidate application for near-term quantum computational resources. Short of large-scale fault-tolerant quantum computers,…

Quantum Physics · Physics 2016-10-25 Nicholas C. Rubin

Hamiltonian light-front quantum field theory provides a framework for calculating both static and dynamic properties of strongly interacting relativistic systems. Invariant masses, correlated parton amplitudes and time-dependent scattering…

Nuclear Theory · Physics 2014-06-10 James P. Vary , Xingbo Zhao , Anton Ilderton , Heli Honkanen , Pieter Maris , Stanley J. Brodsky

We introduce a novel technique for efficiently cooling many-body quantum systems with unknown Hamiltonians down to their ground states with a high fidelity. The technique involves initially applying a strong external field followed by a…

Quantum Physics · Physics 2024-08-20 Tarek A. Elsayed

Variational methods have proven to be excellent tools to approximate ground states of complex many body Hamiltonians. Generic tools like neural networks are extremely powerful, but their parameters are not necessarily physically motivated.…

Strongly Correlated Electrons · Physics 2022-03-04 Agnes Valenti , Eliska Greplova , Netanel H. Lindner , Sebastian D. Huber

The performance of computational methods for many-body physics and chemistry is strongly dependent on the choice of basis used to cast the problem; hence, the search for better bases and similarity transformations is important for progress…

We describe a semidefinite relaxation method which finds lower bounds to the ground state energy of a quantum Hamiltonian subject to Hermitian linear constraints along with approximations of ground state expectation values. We show that…

Strongly Correlated Electrons · Physics 2026-05-29 Michael G. Scheer

We propose a new treatment for the quantum three-body problem. It is based on an expansion of the wave function on harmonic oscillator functions with different sizes in the Jacobi coordinates. The matrix elements of the Hamiltonian can be…

Quantum Physics · Physics 2020-04-17 B. Silvestre-Brac , R. Bonnaz , C. Semay , F. Brau

A new variational basis with well-behaved local approximation properties and multiple output is proposed for Coulomb systems. The trial function has proper behaviour at all Coulomb centres. Nonlinear asymptotic parameters are introduced…

Atomic Physics · Physics 2007-05-23 Vladimir S. Vanyashin

We introduce a quantum generalization of classical kinetic Ising models, described by a certain class of quantum many body master equations. Similarly to kinetic Ising models with detailed balance that are equivalent to certain Hamiltonian…

Quantum Physics · Physics 2015-05-14 R. Augusiak , F. M. Cucchietti , F. Haake , M. Lewenstein

We investigate why, in quantum many-body systems, the adiabatic fidelity and the overlap between the initial state and instantaneous ground states often yield nearly identical values. Our analysis suggests that this phenomenon results from…

Quantum Physics · Physics 2025-11-14 Jyong-Hao Chen , Vadim Cheianov

Estimating ground state energies of many-body Hamiltonians is a central task in many areas of quantum physics. In this work, we give quantum algorithms which, given any $k$-body Hamiltonian $H$, compute an estimate for the ground state…

A variational method for studying the ground state of strongly interacting quantum many-body bosonic systems is presented. Our approach constructs a class of extensive variational non-Gaussian wavefunctions which extend Gaussian states by…

Strongly Correlated Electrons · Physics 2023-02-01 Tian Qian , Jose J. Fernandez-Melgarejo , David Zueco , Javier Molina-Vilaplana

Several protocols are proposed to build continuous energy surfaces of many-body quantum systems, regarding both energy and states. The standard variational principle is augmented with constraints on state overlap, ensuring arbitrary…

Nuclear Theory · Physics 2024-05-29 Paul Carpentier , Nathalie Pillet , Denis Lacroix , Noel Dubray , David Regnier

We present a novel generic framework to approximate the non-equilibrium steady states of dissipative quantum many-body systems. It is based on the variational minimization of a suitable norm of the quantum master equation describing the…

Quantum Physics · Physics 2015-02-20 Hendrik Weimer

We discuss the description of a many-body nuclear system using Hamiltonians that contain the nucleon relativistic kinetic energy and potentials with relativistic corrections. Through the Foldy-Wouthuysen transformation, the field…

Nuclear Theory · Physics 2008-11-26 P. Amore , M. B. Barbaro , A. De Pace

Background: Ab initio many-body methods have been developed over the past ten years to address mid-mass nuclei... As progress in the design of inter-nucleon interactions is made, further efforts must be made to tailor many-body methods.…

Nuclear Theory · Physics 2017-02-01 J. Ripoche , D. Lacroix , D. Gambacurta , J. -P. Ebran , T. Duguet