295 research outputs found
Atomic Bose-Fermi mixed condensates with Boson-Fermion quasi-bound cluster states
The boson-fermion atomic bound states (composite fermion) and their roles for
the phase structures are studied in a bose-fermi mixed condensate of atomic gas
in finite temperature and density. The two-body scattering equation is
formulated for a boson-fermion pair in the mixed condensate with the
Yamaguchi-type potential. By solving the equation, we evaluate the binding
energy of a composite fermion, and show that it has small T-dependence in the
physical region, because of the cancellation of the boson- and fermion-
statistical factors in the equation. We also calculate the phase structure of
the BF mixed condensate under the equilibrium B+F -> BF, and discuss the role
of the composite fermions: the competitions between the degenerate state of the
composite fermions and the Bose-Einstein condensate (BEC) of isolated bosons.
The criterion for the BEC realization is obtained from the
algebraically-derived phase diagrams at T=0.Comment: 5 pages, 3 figure
Nonrigid chiral soliton for the octet and decuplet baryons
Systematic treatment of the collective rotation of the nonrigid chiral
soliton is developed in the SU(3) chiral quark soliton model and applied to the
octet and decuplet baryons. The strangeness degrees of freedom are treated by a
simplified bound-state approach which omits the locality of the kaon wave
function. Then, the flavor rotation is divided into the isospin rotation and
the emission and absorption of the kaon. The kaon Hamiltonian is diagonalized
by the Hartree approximation. The soliton changes the shape according to the
strangeness. The baryons appear as the rotational bands of the combined system
of the soliton and the kaon.Comment: 11 pages(LaTex), 1 figures(eps
Collective ferromagnetism in two-component Fermi-degenerate gas trapped in finite potential
Spin asymmetry of the ground states is studied for the trapped
spin-degenerate (two-component) gases of the fermionic atoms with the repulsive
interaction between different components, and, for large particle number, the
asymmetric (collective ferromagnetic) states are shown to be stable because it
can be energetically favorable to increase the fermi energy of one component
rather than the increase of the interaction energy between up-down components.
We formulate the Thomas-Fermi equations and show the algebraic methods to solve
them. From the Thomas-Fermi solutions, we find three kinds of ground states in
finite system: 1) paramagnetic (spin-symmetric), 2) ferromagnetic (equilibrium)
and 3) ferromagnetic (nonequilibrium) states. We show the density profiles and
the critical atom numbers for these states obtained analytically, and, in
ferromagnetic states, the spin-asymmetries are shown to occur in the central
regions of the trapped gas, and grows up with increasing particle number. Based
on the obtained results, we discuss the experimental conditions and current
difficulties to realize the ferromagnetic states of the trapped atom gas, which
should be overcome.Comment: submit to PR
Instability of the hedgehog shape for the octet baryon in the chiral quark soliton model
In this paper the stability of the hedgehog shape of the chiral soliton is
studied for the octet baryon with the SU(3) chiral quark soliton model. The
strangeness degrees of freedom are treated by a simplified bound-state
approach, which omits the locality of the kaon wave function. The mean field
approximation for the flavor rotation is applied to the model. The classical
soliton changes shape according to the strangeness. The baryon appears as a
rotational band of the combined system of the deformed soliton and the kaon.Comment: 24 pages, LaTeX, 8 eps file
Bosonization and QCD in Two Dimensions
This review is devoted to the application of bosonization techniques to two
dimensional QCD. We start with a description of the ``abelian bosonization".
The methods of the abelian bosonization are applied to several examples like
the Thirring model, the Schwinger model and QCD. The failure of this scheme
to handle flavored fermions is explained. Witten's non-abelian bosonization
rules are summarized including the generalization to the case of fermions with
color and flavor degrees of freedom. We discuss in details the bosonic version
of the mass bilinear of colored-flavored fermions in various schemes. The color
group is gauged and the full bosonized version of massive multiflavor QCD is
written down. The strong coupling limit is taken in the ``product scheme" and
then in the scheme. Once the multiflavor action in
the interesting region of the low energies is written down, we extract the
semiclassical low lying baryonic spectrum. First classical soliton solutions of
the bosonic action are derived. Quantizing the flavor space around those
classical solutions produces the masses as well as the flavor properties of the
two dimensional baryons. In addition low lying multibaryonic solutions are
presented, as well as wave functions and matrix elements of interest, like
content.Comment: 72 pages, WIS-92/54, TAUP-1981-9
Flavor symmetry breaking effects on SU(3) Skyrmion
We study the massive SU(3) Skyrmion model to investigate the flavor symmetry
breaking (FSB) effects on the static properties of the strange baryons in the
framework of the rigid rotator quantization scheme combined with the improved
Dirac quantization one. Both the chiral symmetry breaking pion mass and FSB
kinetic terms are shown to improve the ratio of the strange-light to
light-light interaction strengths and that of the strange-strange to
light-light.Comment: 12 pages, latex, no figure
Out of equilibrium O (N) linear-sigma system - Construction of perturbation theory with gap- and Boltzmann-equations
We establish from first principles a perturbative framework that allows us to
compute reaction rates for processes taking place in nonequilibrium
linear-sigma systems in broken phase. The system of our concern is quasiuniform
system near equilibrium or nonequilibrium quasistationary system. We employ the
closed-time-path formalism and use the so-called gradient approximation. No
further approximation is introduced. In the course of construction of the
framework, we obtain the gap equation that determines the effective masses of
and of , and the generalized Boltzmann equation that describes
the evolution of the number-density functions of and of .Comment: 18 page
Heavy Quark Solitons: Strangeness and Symmetry Breaking
We discuss the generalization of the Callan-Klebanov model to the case of
heavy quark baryons. The light flavor group is considered to be and the
limit of heavy spin symmetry is taken. The presence of the Wess-Zumino-Witten
term permits the neat development of a picture , at the collective level, of a
light diquark bound to a ``heavy" quark with decoupled spin degree of freedom.
The consequences of symmetry breaking are discussed in detail. We point
out that the mass splittings of the heavy baryons essentially measure
the ``low energy" physics once more and that the comparison with experiment is
satisfactory.Comment: 17 pages, RevTEX. Minor typos corrected and new references adde
Magnetic structures and reorientation transitions in noncentrosymmetric uniaxial antiferromagnets
A phenomenological theory of magnetic states in noncentrosymmetric tetragonal
antiferromagnets is developed, which has to include homogeneous and
inhomogeneous terms (Lifshitz-invariants) derived from Dzyaloshinskii-Moriya
couplings. Magnetic properties of this class of antiferromagnets with low
crystal symmetry are discussed in relation to its first known members, the
recently detected compounds Ba2CuGe2O7 and K2V3O8. Crystallographic symmetry
and magnetic ordering in these systems allow the simultaneous occurrence of
chiral inhomogeneous magnetic structures and weak ferromagnetism. New types of
incommensurate magnetic structures are possible, namely, chiral helices with
rotation of staggered magnetization and oscillations of the total
magnetization. Field-induced reorientation transitions into modulated states
have been studied and corresponding phase diagrams are constructed. Structures
of magnetic defects (domain-walls and vortices) are discussed. In particular,
vortices, i.e. localized non-singular line defects, are stabilized by the
inhomogeneous Dzyaloshinskii-Moriya interactions in uniaxial noncentrosymmetric
antiferromagnets.Comment: 18 pages RevTeX4, 13 figure
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