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We review a recent approach for the simulation of many-body interacting systems based on an efficient generalization of the Lanczos method for Quantum Monte Carlo simulations. This technique allows to perform systematic corrections to a…

Strongly Correlated Electrons · Physics 2007-05-23 Sandro Sorella

Density-potential functional theory (DPFT) is an alternative formulation of orbital-free density functional theory that may be suitable for modeling the electronic structure of large systems. To date, DPFT has been applied mainly to quantum…

Materials Science · Physics 2023-04-21 Martin-Isbjörn Trappe , William C. Witt , Sergei Manzhos

The two-site Holstein model represents a first non-trivial paradigm for the interaction between an itinerant charge with a quantum oscillator, a very common topic in different ambits. Exact results can be achieved both analytically and…

Strongly Correlated Electrons · Physics 2008-06-19 Simone Paganelli , Sergio Ciuchi

Variational quantum algorithms have been a promising candidate to utilize near-term quantum devices to solve real-world problems. The powerfulness of variational quantum algorithms is ultimately determined by the expressiveness of the…

Quantum Physics · Physics 2023-05-23 Xiaokai Hou , Qingyu Li , Man-Hong Yung , Xusheng Xu , Zizhu Wang , Chu Guo , Xiaoting Wang

We present a novel, non-parametric form for compactly representing entangled many-body quantum states, which we call a `Gaussian Process State'. In contrast to other approaches, we define this state explicitly in terms of a configurational…

Strongly Correlated Electrons · Physics 2020-11-11 Aldo Glielmo , Yannic Rath , Gabor Csanyi , Alessandro De Vita , George H. Booth

Dynamical quantum simulation may be one of the first applications to see quantum advantage. However, the circuit depth of standard Trotterization methods can rapidly exceed the coherence time of noisy quantum computers. This has led to…

Quantum Physics · Physics 2020-09-08 Benjamin Commeau , M. Cerezo , Zoë Holmes , Lukasz Cincio , Patrick J. Coles , Andrew Sornborger

We present a general variational approach to determine the steady state of open quantum lattice systems via a neural network approach. The steady-state density matrix of the lattice system is constructed via a purified neural network ansatz…

Quantum Physics · Physics 2019-07-03 Filippo Vicentini , Alberto Biella , Nicolas Regnault , Cristiano Ciuti

Recently, a variant of the Bohr Hamiltonian was proposed where the mass term is allowed to depend on the beta variable of nuclear deformation. Analytic solutions of this modified Hamiltonian have been obtained using the Davidson and the…

Nuclear Theory · Physics 2019-12-25 D. Petrellis , Dennis Bonatsos , N. Minkov

In open quantum systems, the Liouvillian gap characterizes the relaxation time toward the steady state. However, accurately computing this quantity is notoriously difficult due to the exponential growth of the Hilbert space and the…

Quantum Physics · Physics 2025-07-29 Xu-Dan Xie , Zheng-Yuan Xue , Dan-Bo Zhang

A new variational principle for optimizing thermal density matrices is introduced. As a first application, the variational many body density matrix is written as a determinant of one body density matrices, which are approximated by…

Plasma Physics · Physics 2009-10-31 Burkhard Militzer , E. L. Pollock

The physics of a closed quantum mechanical system is governed by its Hamiltonian. However, in most practical situations, this Hamiltonian is not precisely known, and ultimately all there is are data obtained from measurements on the system.…

Variational methods have been widely used in soft matter physics for both static and dynamic problems. These methods are mostly based on two variational principles: the variational principle of minimum free energy (MFEVP) and Onsager's…

Soft Condensed Matter · Physics 2022-07-27 Haiqin Wang , Boyi Zou , Jian Su , Dong Wang , Xinpeng Xu

We consider quantum dynamics of the order parameter in the discrete pairing model (Richardson model) in thermodynamic equilibrium. The integrable Richardson Hamiltonian is represented as a direct sum of Hamiltonians acting in different…

Superconductivity · Physics 2014-11-20 Victor Galitski

High-resolution simulations of particle-based kinetic plasma models typically require a high number of particles and thus often become computationally intractable. This is exacerbated in multi-query simulations, where the problem depends on…

Numerical Analysis · Mathematics 2023-07-10 Jan S. Hesthaven , Cecilia Pagliantini , Nicolò Ripamonti

Ground-state properties, such as energies and double occupancies, of a one-dimensional two-band Hubbard model are calculated using a first principles Gutzwiller conjugate gradient minimization theory. The favorable agreement with the…

Strongly Correlated Electrons · Physics 2023-01-18 Zhuo Ye , Feng Zhang , Yong-Xin Yao , Cai-Zhuang Wang , Kai-Ming Ho

The Fermi-Hubbard model is of fundamental importance in condensed-matter physics, yet is extremely challenging to solve numerically. Finding the ground state of the Hubbard model using variational methods has been predicted to be one of the…

Quantum Physics · Physics 2021-01-04 Chris Cade , Lana Mineh , Ashley Montanaro , Stasja Stanisic

Consider a massive (inert) particle impinged from above by N Brownian particles that are instantaneously reflected upon collision with the inert particle. The velocity of the inert particle increases due to the influence of an external…

Probability · Mathematics 2022-12-28 Sayan Banerjee , Amarjit Budhiraja , Benjamin Estevez

We introduce a class of variational states to study ground state properties and real-time dynamics in (2+1)-dimensional compact QED. These are based on complex Gaussian states which are made periodic in order to account for the compact…

High Energy Physics - Theory · Physics 2020-11-19 Julian Bender , Patrick Emonts , Erez Zohar , J. Ignacio Cirac

We investigate an extended version of the periodic Anderson model (the so-called periodic Anderson-Hubbard model) with the aim to understand the role of interaction between conduction electrons in the formation of the heavy-fermion and…

Strongly Correlated Electrons · Physics 2013-05-30 I. Hagymasi , K. Itai , J. Solyom

Density functional perturbation theory is a well-established method to study responses of molecules and solids, especially responses to atomic displacements or to different perturbing fields (electric, magnetic). Like for density functional…

Materials Science · Physics 2024-02-16 Xavier Gonze , Samare Rostami , Christian Tantardini