6,149 research outputs found
Electro-Optic Modulation of Single Photons
We use the Stokes photon of a biphoton pair to set the time origin for
electro-optic modulation of the wave function of the anti-Stokes photon thereby
allowing arbitrary phase and amplitude modulation. We demonstrate conditional
single-photon wave functions composed of several pulses, or instead, having
gaussian or exponential shapes
Sub-wavelength imaging at infrared frequencies using an array of metallic nanorods
We demonstrate that an array of metallic nanorods enables sub-wavelength
(near-field) imaging at infrared frequencies. Using an homogenization approach,
it is theoretically proved that under certain conditions the incoming radiation
can be transmitted by the array of nanorods over a significant distance with
fairly low attenuation. The propagation mechanism does not involve a resonance
of material parameters and thus the resolution is not strongly affected by
material losses and has wide bandwidth. The sub-wavelength imaging with
resolution by silver rods at 30 THz is demonstrated numerically
using full-wave electromagnetic simulator.Comment: 12 pages, 16 figures, submitted to PR
Infinite families of superintegrable systems separable in subgroup coordinates
A method is presented that makes it possible to embed a subgroup separable
superintegrable system into an infinite family of systems that are integrable
and exactly-solvable. It is shown that in two dimensional Euclidean or
pseudo-Euclidean spaces the method also preserves superintegrability. Two
infinite families of classical and quantum superintegrable systems are obtained
in two-dimensional pseudo-Euclidean space whose classical trajectories and
quantum eigenfunctions are investigated. In particular, the wave-functions are
expressed in terms of Laguerre and generalized Bessel polynomials.Comment: 19 pages, 6 figure
Quantum critical transport, duality, and M-theory
We consider charge transport properties of 2+1 dimensional conformal field
theories at non-zero temperature. For theories with only Abelian U(1) charges,
we describe the action of particle-vortex duality on the
hydrodynamic-to-collisionless crossover function: this leads to powerful
functional constraints for self-dual theories. For the n=8 supersymmetric,
SU(N) Yang-Mills theory at the conformal fixed point, exact
hydrodynamic-to-collisionless crossover functions of the SO(8) R-currents can
be obtained in the large N limit by applying the AdS/CFT correspondence to
M-theory. In the gravity theory, fluctuating currents are mapped to fluctuating
gauge fields in the background of a black hole in 3+1 dimensional anti-de
Sitter space. The electromagnetic self-duality of the 3+1 dimensional theory
implies that the correlators of the R-currents obey a functional constraint
similar to that found from particle-vortex duality in 2+1 dimensional Abelian
theories. Thus the 2+1 dimensional, superconformal Yang Mills theory obeys a
"holographic self duality" in the large N limit, and perhaps more generally.Comment: 35 pages, 4 figures; (v2) New appendix on CFT2, corrected
normalization of gauge field action, added ref
Third order superintegrable systems separating in polar coordinates
A complete classification is presented of quantum and classical
superintegrable systems in that allow the separation of variables in
polar coordinates and admit an additional integral of motion of order three in
the momentum. New quantum superintegrable systems are discovered for which the
potential is expressed in terms of the sixth Painlev\'e transcendent or in
terms of the Weierstrass elliptic function
Collapse and stable self-trapping for Bose-Einstein condensates with 1/r^b type attractive interatomic interaction potential
We consider dynamics of Bose-Einstein condensates with long-range attractive
interaction proportional to and arbitrary angular dependence. It is
shown exactly that collapse of Bose-Einstein condensate without contact
interactions is possible only for . Case is critical and requires
number of particles to exceed critical value to allow collapse. Critical
collapse in that case is strong one trapping into collapsing region a finite
number of particles.
Case is supercritical with expected weak collapse which traps rapidly
decreasing number of particles during approach to collapse. For
singularity at is not strong enough to allow collapse but attractive
interaction admits stable self-trapping even in absence of external
trapping potential
Superintegrable systems with spin and second-order integrals of motion
We investigate a quantum nonrelativistic system describing the interaction of
two particles with spin 1/2 and spin 0, respectively. We assume that the
Hamiltonian is rotationally invariant and parity conserving and identify all
such systems which allow additional integrals of motion that are second order
matrix polynomials in the momenta. These integrals are assumed to be scalars,
pseudoscalars, vectors or axial vectors. Among the superintegrable systems
obtained, we mention a generalization of the Coulomb potential with scalar
potential and spin orbital one
.Comment: 32 page
Gauge-invariant electromagnetic response of a chiral px+ipy superconductor
We present a gauge-invariant theory of the electromagnetic response of a
chiral px+ipy superconductor in the clean limit. Due to the spontaneously
broken time-reversal symmetry, the effective action of the system contains an
anomalous term not present in conventional superconductors. As a result, the
electromagnetic charge and current responses contain anomalous terms, which
depend explicitly on the chirality of the superconducting order parameter.
These terms lead to a number of unusual effects, such as coupling of the
transverse currents to the collective plasma oscillations and a possibility of
inducing the charge density by the magnetic field perpendicular to the
conducting planes. We calculate the antisymmetric part of the conductivity
tensor (the intrinsic Hall conductivity) and show that it depends on the wave
vector of the electromagnetic field. We also show that the Mermin-Muzikar
magnetization current and the Hall conductivity are strongly suppressed at high
frequencies. Finally, we discuss implications of the theory to the experiments
in Sr2RuO4.Comment: 22 pages, 4 figures, final version as published in PR
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