11,539 research outputs found
Spontaneous Breaking of Classical PT Symmetry
The classical trajectories of the family of complex PT-symmetric Hamiltonians
() form closed orbits. All such complex
orbits that have been studied in the past are PT symmetric (left-right
symmetric). The periods of these orbits exhibit an unusual dependence on the
parameter . There are regions in of smooth behavior
interspersed with regions of rapid variation. It is demonstrated that the onset
of rapid variation is associated with strange new kinds of classical
trajectories that have never been seen previously. These rare kinds of
trajectories are not PT symmetric and occur only for special rational values of
.Comment: 16 pages, 17 figures, accepted for publication in the Journal of
Mathematical Physic
Entanglement Efficiencies in PT-Symmetric Quantum Mechanics
The degree of entanglement is determined for an arbitrary state of a broad
class of PT-symmetric bipartite composite systems. Subsequently we quantify the
rate with which entangled states are generated and show that this rate can be
characterized by a small set of parameters. These relations allow one in
principle to improve the ability of these systems to entangle states. It is
also noticed that many relations resemble corresponding ones in conventional
quantum mechanics.Comment: Published version with improved figures, 5 pages, 2 figure
Quantum tunneling as a classical anomaly
Classical mechanics is a singular theory in that real-energy classical
particles can never enter classically forbidden regions. However, if one
regulates classical mechanics by allowing the energy E of a particle to be
complex, the particle exhibits quantum-like behavior: Complex-energy classical
particles can travel between classically allowed regions separated by potential
barriers. When Im(E) -> 0, the classical tunneling probabilities persist.
Hence, one can interpret quantum tunneling as an anomaly. A numerical
comparison of complex classical tunneling probabilities with quantum tunneling
probabilities leads to the conjecture that as ReE increases, complex classical
tunneling probabilities approach the corresponding quantum probabilities. Thus,
this work attempts to generalize the Bohr correspondence principle from
classically allowed to classically forbidden regions.Comment: 12 pages, 7 figure
Hydrogeological Investigations in the Pampa of Argentina
The author has identified the following significant results. Satellite imagery in combination with ground investigations allows the identification and delineation of the near surface ground water (depth to ground water, salinity). The degree of precision achieved is greater than that obtainable by conventional ground survey methods alone
On the non-relativistic limit of charge conjugation in QED
Even if at the level of the non-relativistic limit of full QED, C is not a
symmetry, the limit of this operation does exist for the particular case when
the electromagnetic field is considered a classical external object coupled to
the Dirac field. This result extends the one obtained when fermions are
described by the Schroedinger-Pauli equation. We give the expressions for both
the C matrix and the operator for galilean electrons and positrons
interacting with the external electromagnetic field. The result is relevant in
relation to recent experiments with antihydrogen.Comment: 7 page
The Binary Galaxies NGC 147 And NGC 185
Contrary to a previously published claim it is found that the spheroidal
galaxies NGC 147 and NGC 185 probably form a stable binary system. Distance
estimates place this pair on the near side of the Andromeda subgroup of the
Local Group. The fact that this system has probably remained stable over a
Hubble time suggests that it does not have a plunging orbit that brings it very
close to M 31. It is noted that the only two Local Group galaxy pairs, in which
the components have comparable masses, also have similar morphological types.
NGC 147 and NGC 185 are both spheroidals, while the LMC and SMC are both
irregulars. This suggests that protogalaxies of similar mass that are spawned
in similar environments evolve into objects having similar morphologies.Comment: To be published in A.J. October 199
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