367 research outputs found
Trace formula for dielectric cavities III: TE modes
The construction of the semiclassical trace formula for the resonances with
the transverse electric (TE) polarization for two-dimensional dielectric
cavities is discussed. Special attention is given to the derivation of the two
first terms of Weyl's series for the average number of such resonances. The
obtained formulas agree well with numerical calculations for dielectric
cavities of different shapes.Comment: 12 pages, 6 figure
Composite non-Abelian Flux Tubes in N=2 SQCD
Composite non-Abelian vortices in N=2 supersymmetric U(2) SQCD are
investigated. The internal moduli space of an elementary non-Abelian vortex is
CP^1. In this paper we find a composite state of two coincident non-Abelian
vortices explicitly solving the first order BPS equations. Topology of the
internal moduli space T is determined in terms of a discrete quotient CP^2/Z_2.
The spectrum of physical strings and confined monopoles is discussed.
This gives indirect information about the sigma model with target space T.Comment: 37 pages, 7 figures, v3 details added, v4 erratum adde
Semi-classical calculations of the two-point correlation form factor for diffractive systems
The computation of the two-point correlation form factor K(t) is performed
for a rectangular billiard with a small size impurity inside for both periodic
or Dirichlet boundary conditions. It is demonstrated that all terms of
perturbation expansion of this form factor in powers of t can be computed
directly by semiclassical trace formula. The main part of the calculation is
the summation of non-diagonal terms in the cross product of classical orbits.
When the diffraction coefficient is a constant our results coincide with
expansion of exact expressions ontained by a different method.Comment: 42 pages, 10 figures, Late
Analogies between self-duality and stealth matter source
We consider the problem of a self-interacting scalar field nonminimally
coupled to the three-dimensional BTZ metric such that its energy-momentum
tensor evaluated on the BTZ metric vanishes. We prove that this system is
equivalent to a self-dual system composed by a set of two first-order
equations. The self-dual point is achieved by fixing one of the coupling
constant of the potential in terms of the nonminimal coupling parameter. At the
self-dual point and up to some boundary terms, the matter action evaluated on
the BTZ metric is bounded below and above. These two bounds are saturated
simultaneously yielding to a vanishing action for configurations satisfying the
set of self-dual first-order equations.Comment: 6 pages. To be published in Jour. Phys.
Det-Det Correlations for Quantum Maps: Dual Pair and Saddle-Point Analyses
An attempt is made to clarify the ballistic non-linear sigma model formalism
recently proposed for quantum chaotic systems, by the spectral determinant
Z(s)=Det(1-sU) of a quantized map U element of U(N). More precisely, we study
the correlator omega_U(s)= (averaging t over the unit circle).
Identifying the group U(N) as one member of a dual pair acting in the spinor
representation of Spin(4N), omega_U(s) is expanded in terms of irreducible
characters of U(N). In close analogy with the ballistic non-linear sigma model,
a coherent-state integral representation of omega_U(s) is developed. We show
that the leading-order saddle-point approximation reproduces omega_U(s)
exactly, up to a constant factor; this miracle can be explained by interpreting
omega_U(s) as a character of U(2N), for which the saddle-point expansion yields
the Weyl character formula. Unfortunately, this decomposition behaves
non-smoothly in the semiclassical limit, and to make further progress some
averaging over U needs to be introduced. Several averaging schemes are
investigated. In general, a direct application of the saddle-point
approximation to these schemes is demonstrated to give incorrect results; this
is not the case for a `semiclassical averaging scheme', for which all loop
corrections vanish identically. As a side product of the dual pair
decomposition, we compute a crossover between the Poisson and CUE ensembles for
omega_U(s)
Domain Lines as Fractional Strings
We consider N=2 supersymmetric quantum electrodynamics (SQED) with 2 flavors,
the Fayet--Iliopoulos parameter, and a mass term which breaks the
extended supersymmetry down to N=1. The bulk theory has two vacua; at
the BPS-saturated domain wall interpolating between them has a moduli space
parameterized by a U(1) phase which can be promoted to a scalar field
in the effective low-energy theory on the wall world-volume. At small
nonvanishing this field gets a sine-Gordon potential. As a result, only
two discrete degenerate BPS domain walls survive. We find an explicit solitonic
solution for domain lines -- string-like objects living on the surface of the
domain wall which separate wall I from wall II. The domain line is seen as a
BPS kink in the world-volume effective theory. We expect that the wall with the
domain line on it saturates both the and the b
central charges of the bulk theory. The domain line carries the magnetic flux
which is exactly 1/2 of the flux carried by the flux tube living in the bulk on
each side of the wall. Thus, the domain lines on the wall confine charges
living on the wall, resembling Polyakov's three-dimensional confinement.Comment: 28 pages, 13 figure, v2 typos fixed and reference adde
Percolation model for nodal domains of chaotic wave functions
Nodal domains are regions where a function has definite sign. In recent paper
[nlin.CD/0109029] it is conjectured that the distribution of nodal domains for
quantum eigenfunctions of chaotic systems is universal. We propose a
percolation-like model for description of these nodal domains which permits to
calculate all interesting quantities analytically, agrees well with numerical
simulations, and due to the relation to percolation theory opens the way of
deeper understanding of the structure of chaotic wave functions.Comment: 4 pages, 6 figures, Late
Semi-Meissner state and neither type-I nor type-II superconductivity in multicomponent systems
Traditionally, superconductors are categorized as type-I or type-II. Type-I
superconductors support only Meissner and normal states, while type-II
superconductors form magnetic vortices in sufficiently strong applied magnetic
fields. Recently there has been much interest in superconducting systems with
several species of condensates, in fields ranging from Condensed Matter to High
Energy Physics. Here we show that the type-I/type-II classification is
insufficient for such multicomponent superconductors. We obtain solutions
representing thermodynamically stable vortices with properties falling outside
the usual type-I/type-II dichotomy, in that they have the following features:
(i) Pippard electrodynamics, (ii) interaction potential with long-range
attractive and short-range repulsive parts, (iii) for an n-quantum vortex, a
non-monotonic ratio E(n)/n where E(n) is the energy per unit length, (iv)
energetic preference for non-axisymmetric vortex states, "vortex molecules".
Consequently, these superconductors exhibit an emerging first order transition
into a "semi-Meissner" state, an inhomogeneous state comprising a mixture of
domains of two-component Meissner state and vortex clusters.Comment: in print in Phys. Rev. B Rapid Communications. v2: presentation is
made more accessible for a general reader. Latest updates and links to
related papers are available at the home page of one of the authors:
http://people.ccmr.cornell.edu/~egor
On the spacing distribution of the Riemann zeros: corrections to the asymptotic result
It has been conjectured that the statistical properties of zeros of the
Riemann zeta function near z = 1/2 + \ui E tend, as , to the
distribution of eigenvalues of large random matrices from the Unitary Ensemble.
At finite numerical results show that the nearest-neighbour spacing
distribution presents deviations with respect to the conjectured asymptotic
form. We give here arguments indicating that to leading order these deviations
are the same as those of unitary random matrices of finite dimension , where is a well
defined constant.Comment: 9 pages, 3 figure
Trace formula for dieletric cavities : I. General properties
The construction of the trace formula for open dielectric cavities is
examined in detail. Using the Krein formula it is shown that the sum over
cavity resonances can be written as a sum over classical periodic orbits for
the motion inside the cavity. The contribution of each periodic orbit is the
product of the two factors. The first is the same as in the standard trace
formula and the second is connected with the product of reflection coefficients
for all points of reflection with the cavity boundary. Two asymptotic terms of
the smooth resonance counting function related with the area and the perimeter
of the cavity are derived. The coefficient of the perimeter term differs from
the one for closed cavities due to unusual high-energy asymptotics of the
-matrix for the scattering on the cavity. Corrections to the
leading semi-classical formula are briefly discussed. Obtained formulas agree
well with numerical calculations for circular dielectric cavities.Comment: 13 pages, 10 figure
- …