28,088 research outputs found
New nonlinear coherent states and some of their nonclassical properties
We construct a displacement operator type nonlinear coherent state and
examine some of its properties. In particular it is shown that this nonlinear
coherent state exhibits nonclassical properties like squeezing and
sub-Poissonian behaviour.Comment: 3 eps figures. to appear in J.Opt
Phase properties of a new nonlinear coherent state
We study phase properties of a displacement operator type nonlinear coherent
state. In particular we evaluate the Pegg-Barnett phase distribution and
compare it with phase distributions associated with the Husimi Q function and
the Wigner function. We also study number- phase squeezing of this state.Comment: 8 eps figures. to appear in J.Opt
Potential algebra approach to position dependent mass Schroedinger equation
It is shown that for a class of position dependent mass Schroedinger equation
the shape invariance condition is equivalent to a potential symmetry algebra.
Explicit realization of such algebras have been obtained for some shape
invariant potentials
On Higher Derivatives as Constraints in Field Theory: a Geometric Perspective
We formalize geometrically the idea that the (de Donder) Hamiltonian
formulation of a higher derivative Lagrangian field theory can be constructed
understanding the latter as a first derivative theory subjected to constraints.Comment: 7 page
Thermo-magnetic history effects in the vortex state of YNi_2B_2C superconductor
The nature of five-quadrant magnetic isotherms for is different from that for
in a single crystal of YNi2B2C, pointing towards an anisotropic behaviour of
the flux line lattice (FLL). For, a well defined peak effect (PE) and second
magnetization peak (SMP) can be observed and the loop is open prior to the PE.
However, for, the loop is closed and one can observe only the PE. We have
investigated the history dependence of magnetization hysteresis data for by
recording minor hysteresis loops. The observed history dependence in across
different anomalous regions are rationalized on the basis of
su-perheating/supercooling of the vortex matter across the first-order-like
phase transition and possible additional effects due to annealing of the
disordered vortex bundles to the underlying equilibrium state.Comment: 4 pages, 4 figure
Group theoretic dimension of stationary symmetric \alpha-stable random fields
The growth rate of the partial maximum of a stationary stable process was
first studied in the works of Samorodnitsky (2004a,b), where it was
established, based on the seminal works of Rosi\'nski (1995,2000), that the
growth rate is connected to the ergodic theoretic properties of the flow that
generates the process. The results were generalized to the case of stable
random fields indexed by Z^d in Roy and Samorodnitsky (2008), where properties
of the group of nonsingular transformations generating the stable process were
studied as an attempt to understand the growth rate of the partial maximum
process. This work generalizes this connection between stable random fields and
group theory to the continuous parameter case, that is, to the fields indexed
by R^d.Comment: To appear in Journal of Theoretical Probability. Affiliation of the
authors are update
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