2,168,154 research outputs found
On domain shapes and processes in supersymmetric theories
A supersymmetric theory with several scalar superfields generically has
several domain wall type classical configurations which interpolate between
various supersymmetric vacua of the scalar fields. Depending on the couplings,
some of these configurations develop instability and decay into multiple domain
walls, others can form intersections in space. These phenomena are considered
here in a simplest, yet non-trivial, model with two scalar superfields.Comment: 10 pages, LaTeX, 5 figures in LaTe
Bottomonium dipion transitions
Dipion transitions of the subthreshold bottomonium levels with are studied in the
framework of the chiral decay Lagrangian, derived earlier. The channels are considered in the intermediate state and
realistic wave functions of and are used in the
overlap matrix elements. Imposing the Adler zero requirement on the transition
matrix element, one obtains 2d and 1d dipion spectra in reasonable agreement
with experiment.Comment: 34 pages, 18 figure
The problem of Coulomb interactions in the theory of the quantum Hall effect
We summarize the main ingredients of a unifying theory for abelian quantum
Hall states. This theory combines the Finkelstein approach to localization and
interaction effects with the topological concept of an instanton vacuum as well
as Chern-Simons gauge theory. We elaborate on the meaning of a new symmetry
( invariance) for systems with an infinitely ranged interaction
potential. We address the renormalization of the theory and present the main
results in terms of a scaling diagram of the conductances.Comment: 9 pages, 3 figures. To appear in Proceedings of the International
Conference "Mesoscopics and Strongly Correlated Electron Systems", July 2000,
Chernogolovka, Russi
Quantum State Density and Critical Temperature in M-theory
We discuss the asymptotic properties of quantum states density for
fundamental branes which can yield a microscopic interpretation of the
thermodynamic quantities in M-theory. The matching of BPS part of spectrum for
superstring and supermembrane gives the possibility of getting membrane's
results via string calculations. In the weak coupling limit of M-theory the
critical behavior coincides with the first order phase transition in standard
string theory at temperature less than the Hagedorn's temperature . The
critical temperature at large coupling constant is computed by considering
M-theory on manifold with topology .
Alternatively we argue that any finite temperature can be introduced in the
framework of membrane thermodynamics.Comment: 16 pages, published in Mod. Phys. Lett. A16(2001)224
Skyrmions and domain walls in (2+1) dimensions
We study classical solutions of the vector O(3) sigma model in (2+1)
dimensions, spontaneously broken to O(2)xZ2. The model possesses Skyrmion-type
solutions as well as stable domain walls which connect different vacua. We show
that different types of waves can propagate on the wall, including waves
carrying a topological charge. The domain wall can also absorb Skyrmions and,
under appropriate initial conditions, it is possible to emit a Skyrmion from
the wall.Comment: plain tex : 15 pages, 21 Postscript figures, uses epsf.te
Strings with extended non-Abelian gauge interaction
The new generalization of the gauge interaction for the bosonic strings is
found. We consider some quasiequivariant maps from the space of metrics on the
worldsheet to the space of -tuples of one- and two-dimensional loops. The
two-dimensional case is based on the cylinders interacted with a path space
connection. The special 2-gauge string model is formulated using two
1-connections, non-Abelian background symmetric tensor field and non-Abelian
2-form. The branched non-Abelian space-time is the result of our construction.Comment: 11 page
Semiclassical Calculation of Photon-Stimulated Schwinger Pair Creation
We consider the electron-positron pair creation by a photon in an external
constant electric field. The presented treatment is based on a purely
quasiclassical calculation of the imaginary part of the on-shell photon
polarization operator. By using this approach we find the pair production rate
for photons with polarization parallel as well as orthogonal to the external
electric field in the leading order in the parameter , which has
been recently found by other methods. For the orthogonal polarization we also
find a new contribution to the rate, which is leading in the ratio of the
photon energy to the electron mass . We also reproduce by a purely
geometrical calculation the exponential factor in the probability of the
stimulated pair creation at arbitrary energy of the photon.Comment: 16 pages, 4 figure
(Mis-)handling gauge invariance in the theory of the quantum Hall effect II: Perturbative results
The concept of F-invariance, which previously arose in our analysis of the
integral and half-integral quantum Hall effects, is studied in 2+2\epsilon
spatial dimensions. We report the results of a detailed renormalization group
analysis and establish the renormalizability of the (Finkelstein) action to two
loop order. We show that the infrared behavior of the theory can be extracted
from gauge invariant (F-invariant) quantities only. For these quantities
(conductivity, specific heat) we derive explicit scaling functions. We identify
a bosonic quasiparticle density of states which develops a Coulomb gap as one
approaches the metal-insulator transition from the metallic side. We discuss
the consequences of F-invariance for the strong coupling, insulating regime.Comment: 26 pages, 7 figures; minor modifications; submitted to Phys.Rev.
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