相关论文: Interacting Boson Model plus broken-pairs descript…
Superfluid-insulator transitions in a one-dimensional mixture of two-color fermions and scalar bosons are studied within the framework of the Bose-Fermi-Hubbard model. Zero-temperature phase diagrams are constructed for repulsive…
The Dicke spin-boson model is composed by a single bosonic mode and an ensemble of $N$ identical two-level atoms. Assuming thermal equilibrium with a reservoir at temperature $\beta^{-1}$, we consider the situation where the coupling…
A comprehensive decay scheme of $^{93}$Nb below 2 MeV has been constructed from information obtained with the $^{93}$Nb(n,n$^\prime$$\gamma$) and $^{94}$Zr(p,2n$\gamma$$\gamma$)$^{93}$Nb reactions. Branching ratios, lifetimes, transition…
The system of two interacting bosons in a two-dimensional harmonic trap is compared with the system consisting of two noninteracting fermions in the same potential. In particular, we discuss how the properties of the ground state of the…
The fine structure of the low energy part of the nucleon and strange hyperon spectra, which are formed of single states without parity doublets, may be understood in terms of an $SU(3)$ flavor-symmetric quark-quark interaction that…
The paradigmatic spin-boson model considers a spin degree of freedom interacting with an environment typically constituted by a continuum of bosonic modes. This ubiquitous model is of relevance in a number of physical systems where, in…
The two-chain model of correlated fermions, appropriate e.g. for doped spin ladders or carbon nanotubes, is investigated in the weak-interaction limit. It is shown that the model scales to situations with high internal symmetries,…
A model is proposed to study the possible pairing structures of N-boson systems with nonzero spin. Analytical solutions have been obtained. The emphasis is placed on the spin-structures of ground states with attractive or repulsive pairing…
We study ring-exchange models for bosons or XY-spins on the triangular lattice. A four-spin exchange leads to a manifold of ground states with gapless excitations and critical power-law correlations. With a nearest-neighbour exchange,…
The high-spin states in odd-odd $^{194}$Tl nucleus have been studied by populating them using the $^{185,187}$Re($^{13}$C, xn) reactions at 75 MeV of beam energy. $\gamma-\gamma$ coincidence measurement has been performed using the INGA…
Using Density Matrix renormalization group (DMRG), we study the ground state properties of spin one-half fermions and scalar bosons in the soft-core limit, with weak s-wave inter and intra species interactions. We considered the system…
The Hubbard model is used to study an electronic system at half filling. Starting from a functional integral representation the spin-up Grassmann field is integrated out. It is shown that the resulting spinless fermion theory has an…
Spectrum and electric dipole transition rates and relative intensities in $^{152-154}$Sm, $^{156-160}$Gd, $^{160-162}$Dy are studied in the framework of the interacting boson model with s,p,d,f bosons. It is found that E1 transition data…
We extend a non local and non covariant version of the Thirring model in order to describe a many-body system with spin-flipping interactions By introducing a model with two fermion species we are able to avoid the use of non abelian…
Integrability conditions for systems of bosons or fermions with seniority conserving hamiltonians are derived. The conditions are shown to be invariant under a large class of transformations of the interaction matrix elements. Previously…
We consider bosons at Landau level filling $\nu=1$ on a thin torus. In analogy with previous work on fermions at filling $\nu =1/2$, we map the low-energy sector onto a spin-1/2 chain. While the fermionic system may realize the gapless…
Analysis of the recently obtained experimental data for collective states of ^{160}Dy is presented. The Interacting Vector Boson Model (IVBM) was applied for the classification of low lying states with positive parity…
The relativistic interacting quark-diquark model of baryons, recently developed, is here extended to introduce a spin-isospin transition interaction into the mass operator. The refined version of the model is used to calculate the non…
The quasi-realistic free fermionic heterotic-string models provide some of the most detailed examples to explore the phenomenology of string unification. While providing a powerful tool to generate models and their spectra, understanding…
The structure of the $\Delta J = 1$ doublet bands in $^{128}Cs$ is investigated within the framework of the Interacting Vector Boson Fermion Model (IVBFM). A new, purely collective interpretation of these bands is given on the basis of the…