19,833 research outputs found
Three Dimensional Gauge Theory with Topological and Non-topological Mass: Hamiltonian and Lagrangian Analysis
Three dimensional (abelian) gauged massive Thirring model is bosonized in the
large fermion mass limit. A further integration of the gauge field results in a
non-local theory. A truncated version of that is the Maxwell Chern Simons (MCS)
theory with a conventional mass term or MCS Proca theory. This gauge invariant
theory is completely solved in the Hamiltonian and Lagrangian formalism, with
the spectra of the modes determined. Since the vector field constituting the
model is identified (via bosonization) to the fermion current, the charge
current algebra, including the Schwinger term is also computed in the MCS Proca
model.Comment: Eight pages, Latex, No figures
Magnetized Accretion Inside the Marginally Stable Orbit around a Black Hole
Qualitative arguments are presented to demonstrate that the energy density of
magnetic fields in matter accreting onto a black hole inside the marginally
stable orbit is automatically comparable to the rest-mass energy density of the
accretion flow. Several consequences follow: magnetic effects must be
dynamically significant, but cannot be so strong as to dominate; outward energy
transport in Alfven waves may alter the effective efficiency of energy
liberation; and vertical magnetic stresses in this region may contribute to
"coronal" activity.Comment: to appear in Ap. J. Letter
Coherent States for the Non-Linear Harmonic Oscillator
Wave packets for the Quantum Non-Linear Oscillator are considered in the
Generalized Coherent State framerwork. To first order in the non-linearity
parameter the Coherent State behaves very similarly to its classical
counterpart. The position expectation value oscillates in a simple harmonic
manner. The energy-momentum uncertainty relation is time independent as in a
harmonic oscillator. Various features, (such as the Squeezed State nature), of
the Coherent State have been discussed
Planar Two-particle Coulomb Interaction: Classical and Quantum Aspects
The classical and quantum aspects of planar Coulomb interactions have been
studied in detail. In the classical scenario, Action Angle Variables are
introduced to handle relativistic corrections, in the scheme of
time-independent perturbation theory. Complications arising due to the
logarithmic nature of the potential are pointed out. In the quantum case,
harmonic oscillator approximations are considered and effects of the
perturbations on the excited (oscillator) states have been analysed. In both
the above cases, the known 3+1-dimensional analysis is carried through side by
side, for a comparison with the 2+1-dimensional (planar) results.Comment: LaTex, Figures on request, e-mail:<[email protected]
Three flavour Quark matter in chiral colour dielectric model
We investigate the properties of quark matter at finite density and
temperature using the nonlinear chiral extension of Colour Dielectric Model
(CCM). Assuming that the square of the meson fields devlop non- zero vacuum
expectation value, the thermodynamic potential for interacting three flavour
matter has been calculated. It is found that remain zero
in the medium whereas changes in the medium. As a result, and
quark masses decrease monotonically as the temperature and density of the quark
matter is increased.In the present model, the deconfinement density and
temperature is found to be lower compared to lattice results. We also study the
behaviour of pressure and energy density above critical temperature.Comment: Latex file. 5 figures available on request. To appear in Phys. Rev.
Algebraic geometric methods for the stabilizability and reliability of multivariable and of multimode systems
The extent to which feedback can alter the dynamic characteristics (e.g., instability, oscillations) of a control system, possibly operating in one or more modes (e.g., failure versus nonfailure of one or more components) is examined
Local transport in a disorder-stabilized correlated insulating phase
We report the experimental realization of a correlated insulating phase in 2D
GaAs/AlGaAs heterostructures at low electron densities in a limited window of
background disorder. This has been achieved at mesoscopic length scales, where
the insulating phase is characterized by a universal hopping transport
mechanism. Transport in this regime is determined only by the average electron
separation, independent of the topology of background disorder. We have
discussed this observation in terms of a pinned electron solid ground state,
stabilized by mutual interplay of disorder and Coulomb interaction.Comment: 4+delta pages, 4 figures, To appear in the Physical Review B (Rapid
Comm
Supersymmetric Many-particle Quantum Systems with Inverse-square Interactions
The development in the study of supersymmetric many-particle quantum systems
with inverse-square interactions is reviewed. The main emphasis is on quantum
systems with dynamical OSp(2|2) supersymmetry. Several results related to
exactly solved supersymmetric rational Calogero model, including shape
invariance, equivalence to a system of free superoscillators and non-uniqueness
in the construction of the Hamiltonian, are presented in some detail. This
review also includes a formulation of pseudo-hermitian supersymmetric quantum
systems with a special emphasis on rational Calogero model. There are quite a
few number of many-particle quantum systems with inverse-square interactions
which are not exactly solved for a complete set of states in spite of the
construction of infinitely many exact eigen functions and eigenvalues. The
Calogero-Marchioro model with dynamical SU(1,1|2) supersymmetry and a quantum
system related to short-range Dyson model belong to this class and certain
aspects of these models are reviewed. Several other related and important
developments are briefly summarized.Comment: LateX, 65 pages, Added Acknowledgment, Discussions and References,
Version to appear in Jouranl of Physics A: Mathematical and Theoretical
(Commissioned Topical Review Article
Structural studies on encapsulation of tetrahedral and octahedral anions by a protonated octaaminocryptand cage
Structural aspects of the binding of inorganic anions such as perchlorate, hydrogen sulfate, and hexafluorosilicate with the proton cage of octaaminocryptand L1, N(CH2CH2NHCH2-p-xylyl-CH2NHCH2CH2)3N), are examined thoroughly. Crystallographic results for a hexaprotonated perchlorate complex of L1, [(H6L1)6+(ClO4-)]5(ClO4-)·11H2O·CH3CN (1), an octaprotonated hydrogen sulfate complex of L1, [(H8L1)8+(HSO4-)]7(HSO4-)·3H2O·CH3OH (2) and an octaprotonated fluorosilicate complex of L1,[(H8L1)8+(HSiF6-)]3(SiF62-)·(HSiF6-)·15H2O (3), show encapsulation of one perchlorate, hydrogen sulfate and hexafluorosilicate, respectively inside the cage of L1 in their protonated states. Further, detailed structural analysis on complex 1 reveals that the hexaprotonated L1 encapsulates a perchlorate via two N–H···O and five O–H···O hydrogen bonds from protonated secondary nitrogen atoms of L1 and lattice water molecules, respectively. Encapsulated hydrogen sulfate in complex 2 is “glued” inside the octaprotonated cage of L1 via four N–H···O and six C–H···O hydrogen bonds whereas encapsulated HSiF6− in complex 3 has short contacts via six N–H···F and three C–H···F hydrogen bonds with [H8L1]8+. In the cases of complexes 2 and 3, the cryptand L1 in octaprotonated state shows monotopic encapsulation of the guest and the final conformation of these receptors is spherical in nature compared to the elongated shape of hexaprotonated state of L1
in complex 1
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