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We consider a spin-$j$ particle coupled to a structured bath of bosonic modes that decay into thermal baths. We obtain an analytic expression for the reduced spin state and use it to investigate non-Markovian spin dynamics. In the heavily…

Quantum Physics · Physics 2022-04-06 Mattias T. Johnsson , Ben Q. Baragiola , Thomas Volz , Gavin K. Brennen

The Ising model doesn't have a strictly defined dynamics, only a spectrum. There are different ways to equip it with a time dependence e.g. the Glauber or the Kawasaki dynamics, which are both stochastic, but it means there is a master…

Statistical Mechanics · Physics 2021-09-07 Máté Tibor Veszeli , Gábor Vattay

Response functions are central objects in physics. They provide crucial information about the behavior of physical systems, and they can be directly compared with scattering experiments involving particles like neutrons, or photons.…

Quantum Gases · Physics 2019-08-23 Ettore Vitali , Hao Shi , Mingpu Qin , Shiwei Zhang

We present a standard field theoretical derivation of the dynamic density and spin linear response functions of a dilute superfluid Fermi gas in the BCS-BEC crossover in both three and two dimensions. The derivation of the response…

Quantum Gases · Physics 2016-08-09 Lianyi He

In this work we present a very simple and efficient numerical scheme which can be applied to study the dynamics of bosonic systems like, for instance, spinor Bose-Einstein condensates with nonlocal interactions but equally well works for…

Computational Engineering, Finance, and Science · Computer Science 2018-09-03 Krzysztof Gawryluk , Tomasz Karpiuk , Mariusz Gajda , Kazimierz Rzazewski , Miroslaw Brewczyk

We investigate the BCS pairing in a mixture of fermionic polar molecules with two different hyperfine states. We derive a set of coupled gap equations and find that this system supports both spin-singlet and -triplet BCS pairs. We also…

Quantum Gases · Physics 2015-05-14 T. Shi , J. -N. Zhang , C. -P. Sun , S. Yi

The dynamics of the composition of uniform Bose condensates involving two species capable of reciprocal interconversion is treated in terms of a collective quasi-spin model. This collective model quickly reduces to classical form towards…

Quantum Physics · Physics 2007-05-23 A. N. Salgueiro , M. C. Nemes , M. D. Sampaio , A. F. R. de Toledo Piza

We consider a spin chain of fermionic atoms in an optical lattice, interacting with each other by super-exchange interactions. We theoretically investigate the dissipative evolution of the spin chain when it is coupled by magnetic…

Quantum Gases · Physics 2018-07-23 M. Robert-de-Saint-Vincent , P. Pedri , B. Laburthe-Tolra

We present a rigorous derivation of the BCS gap equation for superfluid fermionic gases with point interactions. Our starting point is the BCS energy functional, whose minimizer we investigate in the limit when the range of the interaction…

Mathematical Physics · Physics 2014-03-12 Gerhard Bräunlich , Christian Hainzl , Robert Seiringer

Grassmann Phase Space Theory (GSPT) is applied to the BEC/BCS crossover in cold fermionic atomic gases and used to determine the evolution (over either time or temperature) of the Quantum Correlation Functions (QCF) that specify: (a) the…

Quantum Gases · Physics 2023-02-07 B. J. Dalton , N. M. Kidwani

The BCS model of an isolated superconductor initially prepared in a nonequilibrium state, predicts the existence of interesting dynamical phenomena in the time-dependent order parameter as decaying oscillations, persistent oscillations and…

Superconductivity · Physics 2019-05-22 H. P. Ojeda Collado , Gonzalo Usaj , José Lorenzana , C. A. Balseiro

We introduce a new fermionic variational wavefunction, generalizing the Bardeen-Cooper-Schrieffer (BCS) wavefunction, which is suitable for interacting multi-species spinful systems and sustaining superfluidity. Applications range from…

Superconductivity · Physics 2014-07-02 George Kastrinakis

In this paper we present a very general theoretical framework for addressing fermionic superfluids over the entire range of BCS to Bose Einstein condensation (BEC) crossover in the presence of population imbalance or spin polarization. Our…

Strongly Correlated Electrons · Physics 2011-09-13 Qijin Chen , Yan He , Chih-Chun Chien , K. Levin

The exact solutions of a one-dimensional mixture of spinor bosons and spinor fermions with $\delta$-function interactions are studied. Some new sets of Bethe ansatz equations are obtained by using the graded nest quantum inverse scattering…

Strongly Correlated Electrons · Physics 2015-05-13 Shi-Jian Gu , Junpeng Cao , Shu Chen , Hai-Qing Lin

We address the problem of identifying the (nonstationary) quantum systems that admit supersymmetric dynamical invariants. In particular, we give a general expression for the bosonic and fermionic partner Hamiltonians. Due to the…

Quantum Physics · Physics 2009-11-07 Ali Mostafazadeh

Accurate simulations of thermalization in open quantum systems require a reliable representation of the bath correlation function (BCF). Numerical approaches, such as the hierarchical equations of motion and the pseudomode method,…

Quantum Physics · Physics 2025-11-26 Masaaki Tokieda

We show that the low-frequency modes of a sub-Ohmic bosonic heat bath generate an effective dynamical asymmetry for an intrinsically symmetric quantum spin -1/2. An initially fully polarized spin first decays towards a quasiequilibrium…

Statistical Mechanics · Physics 2015-03-13 P. Nalbach , M. Thorwart

It was recently shown that the BCS formalism leads to several solutions for the energy gap and the equilibrium quasiparticle distribution, with a phase transition temperature which depends on the position of the chemical potential within…

Superconductivity · Physics 2019-08-19 Dragos-Victor Anghel

A two-dimensional (2D) assembly of noninteracting, temperature-dependent, composite-boson Cooper pairs (CPs) in chemical and thermal equilibrium with unpaired fermions is examined in a binary boson-fermion statistical model as the…

Superconductivity · Physics 2016-08-16 M. Casas , N. J. Davidson , M. de Llano , T. A. Mamedov , A. Puente , R. M. Quick , A. Rigo , M. A. Solís

The dynamics of a simple spin chain (2 spins) coupled to bosonic baths at different temperatures is studied. The analytical solution for the reduced density matrix of the system is found. The dynamics and temperature dependence of spin-spin…

Quantum Physics · Physics 2009-05-05 Ilya Sinaysky , Francesco Petruccione , Daniel Burgarth