137 research outputs found
Representations of SU(1,1) in Non-commutative Space Generated by the Heisenberg Algebra
SU(1,1) is considered as the automorphism group of the Heisenberg algebra H.
The basis in the Hilbert space K of functions on H on which the irreducible
representations of the group are realized is explicitly constructed. The
addition theorems are derived.Comment: Latex, 8 page
Quantum Group Covariance and the Braided Structure of Deformed Oscillators
The connection between braided Hopf algebra structure and the quantum group
covariance of deformed oscillators is constructed explicitly. In this context
we provide deformations of the Hopf algebra of functions on SU(1,1). Quantum
subgroups and their representations are also discussed.Comment: 12 pages, to be published in JM
Two Dimensional Fractional Supersymmetry from the Quantum Poincare Group at Roots of Unity
A group theoretical understanding of the two dimensional fractional
supersymmetry is given in terms of the quantum Poincare group at roots of
unity. The fractional supersymmetry algebra and the quantum group dual to it
are presented and the pseudo-unitary, irreducible representations of them are
obtained. The matrix elements of these representations are explicitly
constructed.Comment: 10 pages. Some misprints are corrected. To appear in J. Phys.
More on New Massive Gravity: Exact Solutions
We give a novel description of the recently proposed theory of new massive
gravity (NMG) in three dimensions. We show that in terms of a Dirac type
differential operator acting on the traceless Ricci tensor, the field equations
of the theory reduce to the massive Klein-Gordon type equation with a
curvature-squared source term and to a constraint equation. Under a certain
relation between the source tensor and the traceless Ricci tensor, fulfilled
for constant scalar curvature, the field equations of topologically massive
gravity (TMG) can be thought of as the "square-root" of the massive
Klein-Gordon type equation. Using this fact, we establish a simple framework
for mapping all known algebraic types D and N solutions of TMG into NMG. We
also present new exact solutions of algebraic types D and N which are only
inherent in NMG.Comment: 4 pages, twocolumn REVTeX; Minor cosmetic changes made and new metric
adde
Explaining the subpulse drift velocity of pulsar magnetosphere within the space-charge limited flow model
We try to explain the subpulse drift phenomena adopting the space-charge
limited flow (SCLF) model and comparing the plasma drift velocity in the inner
region of pulsar magnetospheres with the observed velocity of drifting
subpulses. We apply the approach described in a recent paper of van Leeuwen &
Timokhin (2012), where it was shown that the standard estimation of the
subpulse drift velocity through the total value of the scalar potential drop in
the inner gap gives inaccurate results, while the exact expression relating the
drift velocity to the gradient of the scalar potential should be used instead.
After considering a selected sample of sources taken from the catalog of
Weltevrede, Edwards & Stappers (2006) with coherently drifting subpulses and
reasonably known observing geometry, we show that their subpulse drift
velocities would correspond to the drift of the plasma located very close or
above the pair formation front. Moreover, a detailed analysis of PSR B0826-34
and PSR B0818-41 reveals that the variation of the subpulse separation with the
pulse longitude can be successfully explained by the dependence of the plasma
drift velocity on the angular coordinates.Comment: 14 pages, 6 figures, 2 table
General Relativistic Magnetospheres of Slowly Rotating and Oscillating Magnetized Neutron Stars
We study the magnetosphere of a slowly rotating magnetized neutron star
subject to toroidal oscillations in the relativistic regime. Under the
assumption of a zero inclination angle between the magnetic moment and the
angular momentum of the star, we analyze the Goldreich-Julian charge density
and derive a second-order differential equation for the electrostatic
potential. The analytical solution of this equation in the polar cap region of
the magnetosphere shows the modification induced by stellar toroidal
oscillations on the accelerating electric field and on the charge density. We
also find that, after decomposing the oscillation velocity in terms of
spherical harmonics, the first few modes with are responsible for
energy losses that are almost linearly dependent on the amplitude of the
oscillation and that, for the mode , can be a factor
larger than the rotational energy losses, even for a velocity oscillation
amplitude at the star surface as small as . The results
obtained in this paper clarify the extent to which stellar oscillations are
reflected in the time variation of the physical properties at the surface of
the rotating neutron star, mainly by showing the existence of a relation
between and the oscillation amplitude. Finally, we propose a
qualitative model for the explanation of the phenomenology of intermittent
pulsars in terms of stellar oscillations that are periodically excited by star
glitches.Comment: 13 pages, 4 figures, submitted to MNRA
Braided Oscillators
The braided Hopf algebra structure of the generalized oscillator is
investigated. Using the solutions two types of braided Fibonacci oscillators
are introduced. This leads to two types of braided Biedenharn-Macfarlane
oscillators.Comment: 12 pages, latex, some references added, published versio
Summation Formulas for the product of the q-Kummer Functions from
Using the representation of E_q(2) on the non-commutative space
zz^*-qz^*z=\sigma; q0 summation formulas for the product of two,
three and four q-Kummer functions are derived.Comment: Latex, 8 page
Fractional Super Lie Algebras and Groups
n^{th} root of a Lie algebra and its dual (that is fractional supergroup)
based on the permutation group invariant forms are formulated in the Hopf
algebra formalism. Detailed discussion of -graided algebras is
done.Comment: 13 pages, detailed discussion of -graided is adde
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