233 research outputs found
Solitons and giants in matrix models
We present a method for solving BPS equations obtained in the
collective-field approach to matrix models. The method enables us to find BPS
solutions and quantum excitations around these solutions in the one-matrix
model, and in general for the Calogero model. These semiclassical solutions
correspond to giant gravitons described by matrix models obtained in the
framework of AdS/CFT correspondence. The two-field model, associated with two
types of giant gravitons, is investigated. In this duality-based matrix model
we find the finite form of the -soliton solution. The singular limit of this
solution is examined and a realization of open-closed string duality is
proposed.Comment: 17 pages, JHEP cls; v2: final version to appear in JHEP, 2 references
added, physical motivation and interpretation clarifie
Multi-vortex solution in the Sutherland model
We consider the large- Sutherland model in the Hamiltonian
collective-field approach based on the expansion. The Bogomol'nyi limit
appears and the corresponding solutions are given by static-soliton
configurations. They exist only for \l<1, i.e. for the negative coupling
constant of the Sutherland interaction. We determine their creation energies
and show that they are unaffected by higher-order corrections. For \l=1, the
Sutherland model reduces to the free one-plaquette Kogut-Susskind model.Comment: Latex, using ioplppt.sty, 11 page
Solitons and excitations in the duality-based matrix model
We analyse a specific, duality-based generalization of the hermitean matrix
model. The existence of two collective fields enables us to describe specific
excitations of the hermitean matrix model. By using these two fields, we
construct topologically non-trivial solutions (BPS solitons) of the model. We
find the low-energy spectrum of quantum fluctuations around the uniform
solution. Furthermore, we construct the wave functional of the ground state and
obtain the corresponding Green function.Comment: 13 pages,v2: new solutions constructed, title changed accordingl
Waves and Solitons in the Continuum Limit of the Calogero-Sutherland Model
We examine a collection of particles interacting with inverse-square two-body
potentials in the thermodynamic limit. We find explicit large-amplitude density
waves and soliton solutions for the motion of the system. Waves can be
constructed as coherent states of either solitons or phonons. Therefore, either
solitons or phonons can be considered as the fundamental excitations. The
generic wave is shown to correspond to a two-band state in the quantum
description of the system, while the limiting cases of solitons and phonons
correspond to particle and hole excitations.Comment: Version to appear in Physical Rerview Letters; contains some new
results and explanation
Density Correlation Functions in Calogero Sutherland Models
Using arguments from two dimensional Yang-Mills theory and the collective
coordinate formulation of the Calogero-Sutherland model, we conjecture the
dynamical density correlation function for coupling and , where is
an integer. We present overwhelming evidence that the conjecture is indeed
correct.Comment: 12 pages phyzzx, CERN-TH/94.7243 One reference change
Comment on ``Low-dimensional Bose liquids: beyond the Gross-Pitaevskii approximation''
This is a comment on the work of Kolomeisky et al., Phys. Rev. Lett. 85, 1146
(2000). We point out that they are using the wrong form of the energy
functional for one-dimensional fermions. We point out two possible forms of the
energy functional, both of which can be derived from first principles but using
different methods. One is obtained from the collective field theory method,
while the other is derived from the extended Thomas-Fermi method. These two
forms of the energy functional do not support the soliton solutions which are
obtained by Kolomeisky et al.Comment: Revtex, 2 page
SELF-DUAL ANYONS IN UNIFORM BACKGROUND FIELDS
We study relativistic self-dual Chern-Simons-Higgs systems in the presence of
uniform background fields that explicitly break CTP. A rich, but discrete
vacuum structure is found when the gauge symmetry is spontaneously broken,
while the symmetric phase can have an infinite vacuum degeneracy at tree level.
The latter is due to the proliferation of neutral solitonic states that cost
zero energy. Various novel self-dual solitons, such as these, are found in both
the symmetric and the asymmetric phases. Also by considering a similar system
on a two-sphere and the subsequent large sphere limit, we isolate sensible and
finite expressions for the conserved angular and linear momenta, which satisfy
anomalous commutation relations. We conclude with a few remarks on unresolved
issues.Comment: LaTeX, 20 pages, 4 uuencoded figures included
Survey of electronic properties and local structures around Fe in selected multinary chalcogenides
Paper presents detailed studies of local and electronic structure around Fe in Cd0.97Fe0.03Te, Cd0.98Fe0.02Te0.97Se0.03 and Cd0.99Fe0.01Te0.91S0.09 multinary chalcogenides by means of X ray absorption fine structure XAFS , X ray magnetic circular dichroism XMCD and electron paramagnetic resonance EPR measurements. In addition, electronic consequences of Fe incorporation into CdTe semiconductor host were studied by means of first principles calculations. In order to improve accuracy of the calculated total energies, the band gaps and the band edge positions, special attention is paid to the treatment of exchange correlation interaction and the description of highly localized Fe 3d states. Also, the Bader theory of the topological properties of the electron charge density is used to access details of the nature, strength and distribution of the next nearest neighbour bonds. Local and electronic structure around Fe in Cd0.97Fe0.03Te and Cd0.98Fe0.02Te0.97Se0.03 systems have been found to exhibit similar characteristics, since the first coordination sphere around Fe comprises four Te atoms located at approximately the same distance. In Cd0.99Fe0.01Te0.91S0.09 system, however, local bimodal distribution of distances has been revealed, with one Fe Te bond replaced with much shorter Fe S bond, resulting in much stronger crystal field. Along with the crystal field effect, the spin orbit interaction has proven to play decisive role in determining the nature of Fe doped CdTe systems. While the systems with higher Fe concentrations 25 at. are intrinsic insulators, in systems with only 3.125 at. Fe one spin channel contributes to the density of states at the Fermi level, which makes them suitable for spin selective electronic transport application
Particle Production in Matrix Cosmology
We consider cosmological particle production in 1+1 dimensional string
theory. The process is described most efficiently in terms of anomalies, but we
also discuss the explicit mode expansions. In matrix cosmology the usual vacuum
ambiguity of quantum fields in time-dependent backgrounds is resolved by the
underlying matrix model. This leads to a finite energy density for the "in"
state which cancels the effect of anomalous particle production.Comment: 24 pages, 1 figure; v2: references added, minor change
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