42 research outputs found
Supersymmetric Theories on a Non Simply Connected Space-Time
We study the Wess-Zumino theory on where a spatial
coordinate is compactified. We show that when the bosonic and fermionic fields
satisfy the same boundary condition, the theory does not develop a vacuum
energy or tadpoles. We work out the two point functions at one loop and show
that their forms are consistent with the nonrenormalization theorem. However,
the two point functions are nonanalytic and we discuss the structure of this
nonanalyticity.Comment: 10 pages, TEX file, figures upon request from author
On the Ward Identities at Finite Temperature
We show both in 1+1 and 3+1 dimensions that, contrary to the recent
suggestions, the contribution of the fermion loop to the polarization tensor is
manifestly transverse at finite temperature. Some subtleties associated with
the Ward identities at finite temperature are also pointed out.Comment: 12 pages, UR-1361, ER40685-81
Induced fractional valley number in graphene with topological defects
We report on the possibility of valley number fractionalization in graphene
with a topological defect that is accounted for in Dirac equation by a
pseudomagnetic field. The valley number fractionalization is attributable to an
imbalance on the number of one particle states in one of the two Dirac points
with respect to the other and it is related to the flux of the pseudomagnetic
field. We also discuss the analog effect the topological defect might lead in
the induced spin polarization of the charge carriers in graphene
Virial coefficients from 2+1 dimensional QED effective actions at finite temperature and density
From spinor and scalar 2+1 dimensional QED effective actions at finite
temperature and density in a constant magnetic field background, we calculate
the corresponding virial coefficients for particles in the lowest Landau level.
These coefficients depend on a parameter theta related to the time-component of
the gauge field, which plays an essential role for large gauge invariance. The
variation of the parameter theta might lead to an interpolation between
fermionic and bosonic virial coefficients, although these coefficients are
singular for theta=pi/2.Comment: 10 Latex pages, no figures. Version to appear in MPL
Non-polynomial potentials with deformable topological structures
We construct models of self-interacting scalar fields whose BPS solutions
exhibit kink profiles which can be continuously deformed into two-kinks by
varying one of the parameters of the self-interacting potential. The effective
models are obtained from other models with two interacting scalar fields. The
effective models are then applied in a brane-world scenario where we analyze
the consequences of the thicker branes in the warped geometry and in the
localization of gravity.Comment: 16 pages, 5 figure
Path Integral Solubility of a General Two-Dimensional Model
The solubility of a general two dimensional model, which reduces to various
models in different limits, is studied within the path integral formalism.
Various subtleties and interesting features are pointed out.Comment: 7 pages, UR1386, ER40685-83
Trapping neutral fermions with kink-like potentials
The intrinsically relativistic problem of neutral fermions subject to
kink--like potentials () is investigated and the
exact bound-state solutions are found. Apart from the lonely hump solutions for
, the problem is mapped into the exactly solvable Surm-Liouville
problem with a modified P\"{o}schl-Teller potential. An apparent paradox
concerning the uncertainty principle is solved by resorting to the concepts of
effective mass and effective Compton wavelength.Comment: 13 page