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For many-particle systems defined on lattices we investigate the global structure of effective Hamiltonians and observables obtained by means of a suitable basis transformation. We study transformations which lead to effective Hamiltonians…

Strongly Correlated Electrons · Physics 2009-11-10 Christian Knetter , Kai P. Schmidt , Goetz S. Uhrig

We derive a widely-applicable first principles approach for determining two-body, static effective interactions for low-energy Hamiltonians with quantitative accuracy. The algebraic construction rigorously conserves all instantaneous…

Strongly Correlated Electrons · Physics 2024-03-19 Charles J. C. Scott , George H. Booth

We study the entanglement Hamiltonian for finite intervals in infinite quantum chains for two different free-particle systems: coupled harmonic oscillators and fermionic hopping models with dimerization. Working in the ground state, the…

Statistical Mechanics · Physics 2020-10-20 Viktor Eisler , Giuseppe Di Giulio , Erik Tonni , Ingo Peschel

An effective Hamiltonian is considered for hydrogen bonding between two molecules due to the quantum mechanical interaction between the orbitals of the H-atom and the donor and acceptor atoms in the molecules. The Hamiltonian acts on two…

Chemical Physics · Physics 2012-04-03 Ross H. McKenzie

The quantum mechanical motion of the atomic nuclei is considered over a single- or a multi-dimensional subspace of electronic states which is separated by a gap from the rest of the electronic spectrum over the relevant range of nuclear…

Chemical Physics · Physics 2019-07-24 Edit Matyus , Stefan Teufel

We present a basis-set-free approach to the variational quantum eigensolver using an adaptive representation of the spatial part of molecular wavefunctions. Our approach directly determines system-specific representations of qubit…

Quantum Physics · Physics 2021-01-05 Jakob S. Kottmann , Philipp Schleich , Teresa Tamayo-Mendoza , Alán Aspuru-Guzik

We reelaborate on a general method for obtaining effective Hamiltonians that describe different nonlinear optical processes. The method exploits the existence of a nonlinear deformation of the su(2) algebra that arises as the dynamical…

Quantum Physics · Physics 2009-11-07 A. B. Klimov , J. L. Romero , J. Delgado , L. L. Sanchez-Soto

We derive an effective Hamiltonian for the nonlinear process of parametric down conversion in the presence of absorption. Based upon the Green function method for quantizing the electromagnetic field, we first set up Heisenberg's equations…

Quantum Physics · Physics 2015-03-13 J. A. Crosse , Stefan Scheel

We develop an approximate second quantization method for describing the many-particle systems in the presence of bound states of particles at low energies (the kinetic energy of particles is small in comparison to the binding energy of…

Quantum Physics · Physics 2015-06-26 Sergey V. Peletminskii , Yuriy V. Slyusarenko

Distilling highly entangled quantum states from weaker ones is a process that is crucial for efficient and long-distance quantum communication, and has implications for several other quantum information protocols. We introduce the notion of…

Quantum Physics · Physics 2017-10-17 Tamoghna Das , Asutosh Kumar , Amit Kumar Pal , Namrata Shukla , Aditi Sen De , Ujjwal Sen

The pairing interaction among identical nucleons in a single-particle level is treated in the hamiltonian formalism using even Grassmann variables. A minimal (irreducible) basis having a remarkable symmetry property is set up using…

Nuclear Theory · Physics 2009-10-31 M. B. Barbaro , A. Molinari , F. Palumbo , M. R. Quaglia

We describe a general method to identify exact, local parent Hamiltonians for trial states like quantum Hall or spin liquid states, which we have used extensively during the past decade. It can be used to identify exact parent Hamiltonians,…

Strongly Correlated Electrons · Physics 2018-08-29 Martin Greiter , Vera Schnells , Ronny Thomale

This paper presents a useful compact formula for deriving an effective Hamiltonian describing the time-averaged dynamics of detuned quantum systems. The formalism also works for ensemble-averaged dynamics of stochastic systems. To…

Quantum Physics · Physics 2009-11-13 Daniel F. V. James , Jonathan Jerke

We consider the following task: how for a given quantum state $\rho$ to find a grounded Hamiltonian $H$ satisfying the condition $\mathrm{Tr} H\rho\leq E_0<+\infty$ in such a way that the von Neumann entropy of the Gibbs state $\gamma_H(E)$…

Quantum Physics · Physics 2026-01-23 M. E. Shirokov

Quantum annealers are an alternative approach to quantum computing which make use of the adiabatic theorem to efficiently find the ground state of a physically realizable Hamiltonian. Such devices are currently commercially available and…

Quantum Physics · Physics 2021-02-24 Justin Copenhaver , Adam Wasserman , Birgit Wehefritz-Kaufmann

Obtaining the free energies of condensed phase chemical reactions remains computationally prohibitive for high-level quantum mechanical methods. We introduce a hierarchical machine learning framework that bridges this gap by distilling…

Chemical Physics · Physics 2026-03-19 Chenghan Li , Garnet Kin-Lic Chan

We show that any short-range Hamiltonian with a gap between the ground and excited states can be written as a sum of local operators, such that the ground state is an approximate eigenvector of each operator separately. We then show that…

Strongly Correlated Electrons · Physics 2012-07-24 M. B. Hastings

Given a fixed initial state, a desired Hamiltonian, and an amount of time, we provide a complete characterization of the set of Hamiltonians which perform the same action as the desired Hamiltonian on the state of interest. An example is…

Quantum Physics · Physics 2011-11-04 Ian N. Hincks , David G. Cory , Chandrasekhar Ramanathan

Over the past few years, Hamiltonian effective field theory has been successfully applied to studies of nucleon and hyperon excited states. By discretizing the Hamiltonian in a finite volume, one can obtain the energy spectrum and compare…

High Energy Physics - Phenomenology · Physics 2025-12-01 Yu Zhuge , Dan Guo , Zhan-Wei Liu , Derek B. Leinweber , Anthony W. Thomas

Quantum computation of the energy of molecules and materials is one of the most promising applications of fault-tolerant quantum computers. Practical applications require development of quantum algorithms with reduced resource requirements.…