1,532 research outputs found
Kinetic Approach to Fractional Exclusion Statistics
We show that the kinetic approach to statistical mechanics permits an elegant
and efficient treatment of fractional exclusion statistics. By using the
exclusion-inclusion principle recently proposed [Phys. Rev. E49, 5103 (1994)]
as a generalization of the Pauli exclusion principle, which is based on a
proper definition of the transition probability between two states, we derive a
variety of different statistical distributions interpolating between bosons and
fermions. The Haldane exclusion principle and the Haldane-Wu fractional
exclusion statistics are obtained in a natural way as particular cases. The
thermodynamic properties of the statistical systems obeying the generalized
exclusion-inclusion principle are discussed.Comment: 6 pages, REVTE
On the isospin dependence of the mean spin-orbit field in nuclei
By the use of the latest experimental data on the spectra of Sb and
Sn and on the analysis of properties of other odd nuclei adjacent to
doubly magic closed shells the isospin dependence of a mean spin-orbit
potential is defined. Such a dependence received the explanation in the
framework of different theoretical approaches.Comment: 52 pages, Revtex, no figure
Exclusion statistics for fractional quantum Hall states on a sphere
We discuss exclusion statistics parameters for quasiholes and quasielectrons
excited above the fractional quantum Hall states near . We
derive the diagonal statistics parameters from the (``unprojected'') composite
fermion (CF) picture. We propose values for the off-diagonal (mutual)
statistics parameters as a simple modification of those obtained from the
unprojected CF picture, by analyzing finite system numerical spectra in the
spherical geometry.Comment: 9 pages, Revtex, 4 Postscript figures. Universality of the statistics
parameters is stressed, 2 figs adde
Spin ice in a field: quasi-phases and pseudo-transitions
Thermodynamics of the short-range model of spin ice magnets in a field is
considered in the Bethe - Peierls approximation. The results obtained for
[111], [100] and [011] fields agrees reasonably well with the existing
Monte-Carlo simulations and some experiments. In this approximation all
extremely sharp field-induced anomalies are described by the analytical
functions of temperature and applied field. In spite of the absence of true
phase transitions the analysis of the entropy and specific heat reliefs over
H-T plane allows to discern the "pseudo-phases" with specific character of spin
fluctuations and define the lines of more or less sharp "pseudo-transitions"
between them.Comment: 18 pages, 16 figure
Conductance and Shot Noise for Particles with Exclusion Statistics
The first quantized Landauer approach to conductance and noise is generalized
to particles obeying exclusion statistics. We derive an explicit formula for
the crossover between the shot and thermal noise limits and argue that such a
crossover can be used to determine experimentally whether charge carriers in
FQHE devices obey exclusion statistics.Comment: 4 pages, revtex, 1 eps figure include
Identification of nonlinearity in conductivity equation via Dirichlet-to-Neumann map
We prove that the linear term and quadratic nonlinear term entering a
nonlinear elliptic equation of divergence type can be uniquely identified by
the Dirichlet to Neuman map. The unique identifiability is proved using the
complex geometrical optics solutions and singular solutions
Bosonic and fermionic single-particle states in the Haldane approach to statistics for identical particles
We give two formulations of exclusion statistics (ES) using a variable number
of bosonic or fermionic single-particle states which depend on the number of
particles in the system. Associated bosonic and fermionic ES parameters are
introduced and are discussed for FQHE quasiparticles, anyons in the lowest
Landau level and for the Calogero-Sutherland model. In the latter case, only
one family of solutions is emphasized to be sufficient to recover ES;
appropriate families are specified for a number of formulations of the
Calogero-Sutherland model. We extend the picture of variable number of
single-particle states to generalized ideal gases with statistical interaction
between particles of different momenta. Integral equations are derived which
determine the momentum distribution for single-particle states and distribution
of particles over the single-particle states in the thermal equilibrium.Comment: 6 pages, REVTE
Exclusion Statistics in Conformal Field Theory Spectra
We propose a new method for investigating the exclusion statistics of
quasi-particles in Conformal Field Theory (CFT) spectra. The method leads to
one-particle distribution functions, which generalize the Fermi-Dirac
distribution. For the simplest invariant CFTs we find a generalization
of Gentile parafermions, and we obtain new distributions for the simplest
-invariant CFTs. In special examples, our approach reproduces
distributions based on `fractional exclusion statistics' in the sense of
Haldane. We comment on applications to fractional quantum Hall effect edge
theories.Comment: 4 pages, 1 figure, LaTeX (uses revtex
Resonance regimes of scattering by small bodies with impedance boundary conditions
The paper concerns scattering of plane waves by a bounded obstacle with
complex valued impedance boundary conditions. We study the spectrum of the
Neumann-to-Dirichlet operator for small wave numbers and long wave asymptotic
behavior of the solutions of the scattering problem. The study includes the
case when is an eigenvalue or a resonance. The transformation from the
impedance to the Dirichlet boundary condition as impedance grows is described.
A relation between poles and zeroes of the scattering matrix in the non-self
adjoint case is established. The results are applied to a problem of scattering
by an obstacle with a springy coating. The paper describes the dependence of
the impedance on the properties of the material, that is on forces due to the
deviation of the boundary of the obstacle from the equilibrium position
Absence of a Spin Liquid Phase in the Hubbard Model on the Honeycomb Lattice
A spin liquid is a novel quantum state of matter with no conventional order
parameter where a finite charge gap exists even though the band theory would
predict metallic behavior. Finding a stable spin liquid in two or higher
spatial dimensions is one of the most challenging and debated issues in
condensed matter physics. Very recently, it has been reported that a model of
graphene, i.e., the Hubbard model on the honeycomb lattice, can show a spin
liquid ground state in a wide region of the phase diagram, between a semi-metal
(SM) and an antiferromagnetic insulator (AFMI). Here, by performing numerically
exact quantum Monte Carlo simulations, we extend the previous study to much
larger clusters (containing up to 2592 sites), and find, if any, a very weak
evidence of this spin liquid region. Instead, our calculations strongly
indicate a direct and continuous quantum phase transition between SM and AFMI.Comment: 15 pages with 7 figures and 9 tables including supplementary
information, accepted for publication in Scientific Report
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