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The recent interest in aspects common to quantum information and condensed matter has prompted a prosperous activity at the border of these disciplines that were far distant until few years ago. Numerous interesting questions have been…

Quantum Physics · Physics 2008-11-26 Luigi Amico , Rosario Fazio , Andreas Osterloh , Vlatko Vedral

We present a family of many-body models which are exactly solvable analytically. The models are an extended n-body interaction Lipkin-Meshkov-Glick model which considers spin-flip terms which are associated with the interaction of an…

Quantum Physics · Physics 2008-11-26 I. Fuentes-Schuller , P. Barberis-Blostein

The key problem of statistical physics standing over one hundred years is how to exactly calculate the partition function (or free energy) of many-body interaction systems, which severely hinders application of the theory for realistic…

Statistical Mechanics · Physics 2019-04-26 Bo-Yuan Ning , Le-Cheng Gong , Tsu-Chien Weng , Xi-Jing Ning

We study the mechanism of thermalization in finite many-fermion systems with random $k$-body interactions in presence of a mean-field. The system Hamiltonian $H$, for $m$ fermions in $N$ single particle states with $k$-body interactions, is…

Chaotic Dynamics · Physics 2023-04-05 Priyanka Rao , N. D. Chavda

The in-medium similarity renormalization group (IMSRG) is a popular many-body method used for computations of nuclei. It solves the many-body Schr\"odinger equation through a continuous unitary transformation of the many-body Hamiltonian.…

Nuclear Theory · Physics 2026-04-28 Matthias Heinz

It is shown that statistical mechanics is applicable to isolated quantum systems with finite numbers of particles, such as complex atoms, atomic clusters, or quantum dots in solids, where the residual two-body interaction is sufficiently…

Statistical Mechanics · Physics 2016-08-31 V. V. Flambaum , A. A. Gribakina , G. F. Gribakin , I. V. Ponomarev

To overcome the limitations of existing algorithms for solving self-bound quantum many-body problems -- such as those encountered in nuclear and particle physics -- that access only a restricted subset of energy levels and provide limited…

Nuclear Theory · Physics 2025-05-27 Weijie Du , Yangguang Yang , Zixin Liu , Chao Yang , James P. Vary

We present a formal derivation of the many-body perturbation theory for a system of electrons and bosons subject to a nonlinear electron-boson coupling. The interaction is treated at an arbitrary high order of bosons scattered. The…

Strongly Correlated Electrons · Physics 2018-08-15 Andrea Marini , Yaroslav Pavlyukh

Solving for the lowest energy eigenstate of the many-body Schrodinger equation is a cornerstone problem that hinders understanding of a variety of quantum phenomena. The difficulty arises from the exponential nature of the Hilbert space…

We introduce a model of multi-agent dynamics for self-organised motion; individuals travel at a constant speed while trying to adopt the averaged body attitude of their neighbours. The body attitudes are represented through unitary…

Mathematical Physics · Physics 2017-06-21 Pierre Degond , Amic Frouvelle , Sara Merino-Aceituno , Ariane Trescases

Open quantum systems host a wide range of intriguing phenomena, yet their simulation on well-controlled quantum devices is challenging, owing to the exponential growth of the Hilbert space and the inherently non-unitary nature of the…

While general quantum many-body systems require exponential resources to be simulated on a classical computer, systems of non-interacting fermions can be simulated exactly using polynomially scaling resources. Such systems may be of…

Strongly Correlated Electrons · Physics 2019-12-18 Norbert Schuch , Bela Bauer

Understanding the dynamics of open quantum many-body systems is a major problem in quantum matter. Specifically, efficiently solving the spectrum of the Liouvillian superoperator governing such dynamics remains a critical open challenge.…

Quantum Physics · Physics 2024-11-26 Guangze Chen , Jose L. Lado , Fei Song

The article summarizes and consolidates investigations on hyperbolic complex numbers with respect to the Klein-Gordon equation for fermions and bosons. The hyperbolic complex numbers are applied in the sense that complex extensions of…

Mathematical Physics · Physics 2014-07-01 S. Ulrych

Artificial neural networks have been recently introduced as a general ansatz to compactly represent many- body wave functions. In conjunction with Variational Monte Carlo, this ansatz has been applied to find Hamil- tonian ground states and…

Strongly Correlated Electrons · Physics 2018-10-24 Kenny Choo , Giuseppe Carleo , Nicolas Regnault , Titus Neupert

The Lipkin-Meshkov-Glick is a simple, but not trivial, model of a quantum many-body system which allows us to solve the many-body Schr\"odinger equation without making any approximation. The model, which in its unperturbed case is composed…

Nuclear Theory · Physics 2018-06-01 Giampaolo Co' , Stefano De Leo

Nonequilibrium dynamics of quantum many-body systems is challenging for classical computing, providing opportunities for demonstrating practical quantum computational advantage with analogue quantum simulators. Owing to the intimate…

In this thesis we present new results relevant to two important problems in quantum information science: the development of a theory of entanglement and the exploration of the use of controlled quantum systems to the simulation of quantum…

Quantum Physics · Physics 2008-10-21 Fernando G. S. L. Brandao

Paradigmatic spin Hamiltonians in condensed matter and quantum sensing typically utilize pair-wise or 2-body interactions between constituents in the material or ensemble. However, there is growing interest in exploring more general…

We develop a variational approach at finite temperature that incorporates many-body correlation self-consistently. The grand potential is constructed in terms of Green's function expressed by the variational parameters. We apply this…

Quantum Gases · Physics 2019-05-30 Akimitsu Kirikoshi , Wataru Kohno , Takafumi Kita