168 research outputs found
Supersymmetry Across Nanoscale Heterojunction
We argue that supersymmetric transformation could be applied across the
heterojunction formed by joining of two mixed semiconductors. A general
framework is described by specifying the structure of ladder operators at the
junction for making quantitative estimation of physical quantities. For a
particular heterojunction device, we show that an exponential grading inside a
nanoscale doped layer is amenable to exact analytical treatment for a class of
potentials distorted by the junctions through the solutions of transformed
Morse-Type potentials.Comment: 7 pages, 2 figure
Non-isospectrality of the generalized Swanson Hamiltonian and harmonic oscillator
The generalized Swanson Hamiltonian with , can be transformed into an equivalent Hermitian Hamiltonian
with the help of a similarity transformation. It is shown that the equivalent
Hermitian Hamiltonian can be further transformed into the harmonic oscillator
Hamiltonian so long as constant. However, the
main objective of this paper is to show that though the commutator of
and is constant, the generalized Swanson
Hamiltonian is not necessarily isospectral to the harmonic oscillator. Reason
for this anomaly is discussed in the frame work of position dependent mass
models by choosing as the inverse square root of the mass function.Comment: Accepted in Journal of Physics A. Comments are welcom
Isospectrality of conventional and new extended potentials, second-order supersymmetry and role of PT symmetry
We develop a systematic approach to construct novel completely solvable
rational potentials. Second-order supersymmetric quantum mechanics dictates the
latter to be isospectral to some well-studied quantum systems.
symmetry may facilitate reconciling our approach to the requirement that the
rationally-extended potentials be singularity free. Some examples are shown.Comment: 13 pages, no figure, some additions to introduction and conclusion, 4
more references; to be published in Special issue of Pramana - J. Phy
Classification of the conditionally observable spectra exhibiting central symmetry
We show how in PT-symmetric 2J-level quantum systems the assumption of an
upside-down symmetry (or duality) of their spectra simplifies their
classification based on the non-equivalent pairwise mergers of the energy
levels.Comment: 10 pp. 3 figure
Decoupling of pion coupling f_{\pi} from quarks at high density in three models, and its possible observational consequences
Chiral symmetry is restored at high density, quarks become nearly massless
and pion, the Goldstone of the symmetry breaking decouples from the quarks.
What happens at high density is important for finding the density dependence of
Strange Quark Matter (SQM), - which in turn is relevant for understanding the
structure of compact stars.Comment: 13 pages, 2 figures. Accepted for publication in PL
Strange Pulsar Hypothesis
It appears that there is a genuine shortage of radio pulsars with surface
magnetic fields significantly smaller than Gauss. We propose that
the pulsars with very low magnetic fields are actually strange stars locked in
a state of minimum free energy and therefore at a limiting value of the
magnetic field which can not be lowered by the system spontaneously.Comment: 4 pages, 1 figure, uses LaTeX2e(mn2e.cls) and astrobib(mnras.bst),
accepted in MNRA
Mean field baryon magnetic moments and sumrules
New developments have spurred interest in magnetic moments (-s) of
baryons. The measurement of some of the decuplet -s and the findings of
new sumrules from various methods are partly responsible for this renewed
interest. Our model, inspired by large colour approximation, is a relativistic
self consistent mean field description with a modified Richardson potential and
is used to describe the -s and masses of all baryons with up (u), down (d)
and strange (s) quarks. We have also checked the validity of the Franklin
sumrule (referred to as CGSR in the literature) and sumrules of Luty,
March-Russell and White. We found that our result for sumrules matches better
with experiment than the non-relativistic quark model prediction. We have also
seen that quark magnetic moments depend on the baryon in which they belong
while the naive quark model expects them to be constant.Comment: 7 pages, no figure, uses epl.cl
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