8,452 research outputs found
Non-minimal Einstein-Yang-Mills-Higgs theory: Associated, color and color-acoustic metrics for the Wu-Yang monopole model
We discuss a non-minimal Einstein-Yang-Mills-Higgs model with uniaxial
anisotropy in the group space associated with the Higgs field. We apply this
theory to the problem of propagation of color and color-acoustic waves in the
gravitational background related to the non-minimal regular Wu-Yang monopole.Comment: 14 pages, no figure
Bosonizing one-dimensional cold atomic gases
We present results for the long-distance asymptotics of correlation functions
of mesoscopic one-dimensional systems with periodic and open (Dirichlet)
boundary conditions, as well as at finite temperature in the thermodynamic
limit. The results are obtained using Haldane's harmonic-fluid approach (also
known as ``bosonization''), and are valid for both bosons and fermions, in
weakly and strongly interacting regimes. The harmonic-fluid approach and the
method to compute the correlation functions using conformal transformations are
explained in great detail. As an application relevant to one-dimensional
systems of cold atomic gases, we consider the model of bosons interacting with
a zero-range potential. The Luttinger-liquid parameters are obtained from the
exact solution by solving the Bethe-ansatz equations in finite-size systems.
The range of applicability of the approach is discussed, and the prefactor of
the one-body density matrix of bosons is fixed by finding an appropriate
parametrization of the weak-coupling result. The formula thus obtained is shown
to be accurate, when compared with recent diffusion Montecarlo calculations,
within less than 10%. The experimental implications of these results for Bragg
scattering experiments at low and high momenta are also discussed.Comment: 39 pages + 14 EPS figures; typos corrected, references update
Shot Noise Enhancement in Resonant Tunneling Structures in a Magnetic Field
We have observed that the shot noise of tunnel current, I, in
GaSb-AlSb-InAs-AlSb-GaSb double-barrier structure under a magnetic field can
exceed 2qI. The measurements were done at T=4K in fields up to 5T parallel to
the current. The noise enhancement occurred at each of the several
negative-differential conductance regions induced by the tunneling of holes
through Landau levels in the InAs quantum well. The amount of the enhancement
increased with the strength of the negative conductance and reached values up
to 8qI. These results are explained qualitatively by fluctuations of the
density of states in the well, but point out the need for a detailed theory of
shot noise enhancement in resonant tunneling devices.Comment: 4 pages, RevTex, 3 figure
Coulomb drag shot noise in coupled Luttinger liquids
Coulomb drag shot noise has been studied theoretically for 1D interacting
electron systems, which are realized e.g. in single-wall nanotubes. We show
that under adiabatic coupling to external leads, the Coulomb drag shot noise of
two coupled or crossed nanotubes contains surprising effects, in particular a
complete locking of the shot noise in the tubes. In contrast to Coulomb drag of
the average current, the noise locking is based on a symmetry of the underlying
Hamiltonian and is not limited to asymptotically small energy scales.Comment: 4 pages Revtex, accepted for publication in PR
Freezing of dynamical exponents in low dimensional random media
A particle in a random potential with logarithmic correlations in dimensions
is shown to undergo a dynamical transition at . In
exact results demonstrate that , the static glass transition
temperature, and that the dynamical exponent changes from at high temperature to in the glass phase. The same
formulae are argued to hold in . Dynamical freezing is also predicted in
the 2D random gauge XY model and related systems. In a mapping between
dynamics and statics is unveiled and freezing involves barriers as well as
valleys. Anomalous scaling occurs in the creep dynamics.Comment: 5 pages, 2 figures, RevTe
BIOLOGICAL AMMONIA REMOVAL BY SUBMERGED AERATED FILTER FROM HANOI GROUND WATER
Joint Research on Environmental Science and Technology for the Eart
The Effect of the Pairing Interaction on the Energies of Isobar Analog Resonances in Sb and Isospin Admixture in Sn Isotopes
In the present study, the effect of the pairing interaction and the isovector
correlation between nucleons on the properties of the isobar analog resonances
(IAR) in Sb isotopes and the isospin admixture in Sn
isotopes is investigated within the framework of the quasiparticle random phase
approximation (QRPA). The form of the interaction strength parameter is related
to the shell model potential by restoring the isotopic invariance of the
nuclear part of the total Hamiltonian. In this respect, the isospin admixtures
in the Sn isotopes are calculated, and the dependence of the
differential cross section and the volume integral for the
Sn(He,t)Sb reactions at E(He) MeV occurring by the excitation
of IAR on mass number A is examined. Our results show that the calculated value
for the isospin mixing in the Sn isotope is in good agreement with Colo
et al.'s estimates , and the obtained values for the volume integral
change within the error range of the value reported by Fujiwara et al.
(535 MeV fm). Moreover, it is concluded that although the
differential cross section of the isobar analog resonance for the (He,t)
reactions is not sensitive to pairing correlations between nucleons, a
considerable effect on the isospin admixtures in isotopes can be
seen with the presence of these correlations.Comment: 16 pages, 5 EPS figures and 2 tables, Late
Dynamical Properties of the 1/r^2-Type Supersymmetric t-J Model in a Magnetic Field: Manifestation of Spin-Charge Separation
Quasi-particle picture in a magnetic field is pursued for dynamical spin and
charge correlation functions of the one-dimensional supersymmetric t-J model
with inverse-square interaction. With use of exact diagonalization and the
asymptotic Bethe-ansatz equations for finite systems, excitation contents of
relevant excited states are identified which are valid in the thermodynamic
limit. The excitation contents are composed of spinons, antispinons, holons and
antiholons obeying fractional statistics. Both longitudinal and transverse
components of the dynamical spin structure factor are independent of the
electron density in the region where only quasi-particles with spin degrees of
freedom (spinons and antispinons) contribute. The dynamical charge structure
factor does not depend on the spin-polarization density in the region where
only quasi-particles with charge (holons and antiholons) are excited. These
features indicate the strong spin-charge separation in dynamics, reflecting the
high symmetry of the model.Comment: 10 pages, 1 table (PS file), 15 figures (JPEG file). Submitted to J.
Phys. Soc. Jp
The Constraints of Conformal Symmetry on RG Flows
If the coupling constants in QFT are promoted to functions of space-time, the
dependence of the path integral on these couplings is highly constrained by
conformal symmetry. We begin the present note by showing that this idea leads
to a new proof of Zamolodchikov's theorem. We then review how this simple
observation also leads to a derivation of the a-theorem. We exemplify the
general procedure in some interacting theories in four space-time dimensions.
We concentrate on Banks-Zaks and weakly relevant flows, which can be controlled
by ordinary and conformal perturbation theories, respectively. We compute
explicitly the dependence of the path integral on the coupling constants and
extract the change in the a-anomaly (this agrees with more conventional
computations of the same quantity). We also discuss some general properties of
the sum rule found in arXiv:1107.3987 and study it in several examples.Comment: 25 pages, 5 figure
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