1,071 research outputs found
Scattering in the PT-symmetric Coulomb potential
Scattering on the -symmetric Coulomb potential is studied along a
U-shaped trajectory circumventing the origin in the complex plane from
below. This trajectory reflects symmetry, sets the appropriate
boundary conditions for bound states and also allows the restoration of the
correct sign of the energy eigenvalues. Scattering states are composed from the
two linearly independent solutions valid for non-integer values of the 2L
parameter, which would correspond to the angular momentum in the usual
Hermitian setting. Transmission and reflection coefficients are written in
closed analytic form and it is shown that similarly to other -symmetric scattering systems the latter exhibit handedness effect.
Bound-state energies are recovered from the poles of the transmission
coefficients.Comment: Journal of Physics A: Mathematical and Theoretical 42 (2009) to
appea
Reflectionless PT-symmetric potentials in the one-dimensional Dirac equation
We study the one-dimensional Dirac equation with local PT-symmetric
potentials whose discrete eigenfunctions and continuum asymptotic
eigenfunctions are eigenfunctions of the PT operator, too: on these conditions
the bound-state spectra are real and the potentials are reflectionless and
conserve unitarity in the scattering process. Absence of reflection makes it
meaningful to consider also PT-symmetric potentials that do not vanish
asymptotically.Comment: 24 pages, to appear in J. Phys. A : Math. Theor; one acknowledgement
and one reference adde
New approach to (quasi)-exactly solvable Schrodinger equations with a position-dependent effective mass
By using the point canonical transformation approach in a manner distinct
from previous ones, we generate some new exactly solvable or quasi-exactly
solvable potentials for the one-dimensional Schr\"odinger equation with a
position-dependent effective mass. In the latter case, SUSYQM techniques
provide us with some additional new potentials.Comment: 11 pages, no figur
Open Charm Enhancement in Pb+Pb Collisions at SPS
The statistical coalescence model for the production of open and hidden charm
is considered within the canonical ensemble formulation. The data for the
J/\psi multiplicity in Pb+Pb collisions at 158 A GeV are used for the model
prediction of the open charm yield. We find a strong enhancement of the open
charm production, by a factor of about 2--4, over the standard hard-collision
model extrapolation from nucleon-nucleon to nucleus-nucleus collisions. A
possible mechanism of the open charm enhancement in A+A collisions at the SPS
energies is proposed.Comment: 4 pages, Late
Parton coalescence and antiproton/pion anomaly at RHIC
Coalescence of minijet partons with the partons from the quark-gluon plasma
formed in relativistic heavy ion collisions is suggested as the mechanism for
production of hadrons with intermediate transverse momentum. The resulting
enhanced antiproton and pion yields at intermediate transverse momentum gives a
plausible explanation for the observed large antiproton to pion ratio. With
further increasing momentum, the ratio is predicted to decrease and approach
the small value given by independent fragmentations of minijet partons after
their energy loss in the quark-gluon plasma.Comment: 4 pages, 3 figures, version to appear in Phys. Rev. Let
Quantum Hamilton-Jacobi analysis of PT symmetric Hamiltonians
We apply the quantum Hamilton-Jacobi formalism, naturally defined in the
complex domain, to a number of complex Hamiltonians, characterized by discrete
parity and time reversal (PT) symmetries and obtain their eigenvalues and
eigenfunctions. Examples of both quasi-exactly and exactly solvable potentials
are analyzed and the subtle differences, in the singularity structures of their
quantum momentum functions, are pointed out. The role of the PT symmetry in the
complex domain is also illustrated.Comment: 11 page
Jets and produced particles in pp collisions from SPS to RHIC energies for nuclear applications
Higher-order pQCD corrections play an important role in the reproduction of
data at high transverse momenta in the energy range 20 GeV GeV. Recent calculations of photon and pion production in collisions
yield detailed information on the next-to-leading order contributions. However,
the application of these results in proton-nucleus and nucleus-nucleus
collisions is not straightforward. The study of nuclear effects requires a
simplified understanding of the output of these computations. Here we summarize
our analysis of recent calculations, aimed at handling the NLO results by
introducing process and energy-dependent factors.Comment: 4 pages with 5 eps figures include
Motion of a spin 1/2 particle in shape invariant scalar and magnetic fields
We study the motion of a spin 1/2 particle in a scalar as well as a magnetic
field within the framework of supersymmetric quantum mechanics(SUSYQM). We also
introduce the concept of shape invariant scalar and magnetic fields and it is
shown that the problem admits exact analytical solutions when such fields are
considered.Comment: 14 page
Pseudo-Hermiticity and some consequences of a generalized quantum condition
We exploit the hidden symmetry structure of a recently proposed non-Hermitian
Hamiltonian and of its Hermitian equivalent one. This sheds new light on the
pseudo-Hermitian character of the former and allows access to a generalized
quantum condition. Special cases lead to hyperbolic and Morse-like potentials
in the framework of a coordinate-dependent mass model.Comment: 10 pages, no figur
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