Spatially inhomogeneous population dynamics: beyond the mean field approximation
نویسندگان
چکیده
منابع مشابه
Boson-fermion Model beyond Mean-field Approximation
A model of hybridized bosons and fermions is studied beyond the mean field approximation. The divergent boson self-energy at zero temperature makes the Cooper pairing of fermions impossible. The frequency and momentum dependence of the self-energy and the condensation temperature T c of initially localized bosons are calculated analytically. The value of the boson condensation temperature T c i...
متن کاملMean Field Approximation in Conformation Dynamics
We propose a new approach to the transfer operator based analysis of the conformation dynamics of molecules. It is based on a statistical independence ansatz for the eigenfunctions of the operator related to a partitioning into subsystems. Numerical tests performed on small systems show excellent qualitative agreement between mean field and exact model, at greatly reduced computational cost.
متن کاملComment on “ Boson - fermion model beyond the mean - field approximation ”
In a recent paper [Alexandrov A S 1996 J. Phys.: Condens. Matter 8 6923–32; cond-mat/9603111], it has been suggested that there is no Cooper pairing in boson-fermion models of superconductivity. We show that this conjecture is based on an inconsistent approximation that violates an exact identity. Quite generally, the divergence of the fermion t-matrix (the Thouless criterion) is accompanied by...
متن کاملIn-medium chiral perturbation theory beyond the mean–field approximation
An explicit expression for the generating functional of two–flavor low–energy QCD with external sources in the presence of non-vanishing nucleon densities has been derived recently [1]. Within this approach we derive power counting rules for the calculation of in-medium pion properties. We develop the so-called standard rules for residual nucleon energies of the order of the pion mass and a mod...
متن کاملNambu-Jona-Lasinio models beyond the mean-field approximation.
Inspired by the model of Nambu and Jona-Lasinio, various Lagrangians are considered for a system of interacting quarks. Employing standard techniques of many-body theory, the scalar part of the quark self-energy is calculated including terms up to second-order in the interaction. Results obtained for the single-particle Green’s function are compared with those which only account for the mean-fi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Physics A: Mathematical and Theoretical
سال: 2019
ISSN: 1751-8113,1751-8121
DOI: 10.1088/1751-8121/ab2808