46,655 research outputs found
Transmission coefficient and two-fold degenerate discrete spectrum of spin-1 bosons in a double-step potential
The scattering of spin-1 bosons in a nonminimal vector double-step potential
is described in terms of eigenstates of the helicity operator and it is shown
that the transmission coefficient is insensitive to the choice of the
polarization of the incident beam. Poles of the transmission amplitude reveal
the existence of a two-fold degenerate spectrum. The results are interpreted in
terms of solutions of two coupled effective Schr\"{o}dinger equations for a
finite square well with additional -functions situated at the borders.Comment: arXiv admin note: substantial text overlap with arXiv:1203.119
Entanglement and Bell's inequality violation above room temperature in metal carboxylates
In the present work we show that a special family of materials, the metal
carboxylates, may have entangled states up to very high temperatures. From
magnetic susceptibility measurements, we have estimated the critical
temperature below which entanglement exists in the cooper carboxylate
\{Cu(OCH)\}\{Cu(OCH)(2-methylpyridine)\}, and we have
found this to be above room temperature ( K). Furthermore, the
results show that the system remains maximally entangled until close to K and the Bell's inequality is violated up to nearly room temperature
( K)
Driving-dependent damping of Rabi oscillations in two-level semiconductor systems
We propose a mechanism to explain the nature of the damping of Rabi
oscillations with increasing driving-pulse area in localized semiconductor
systems, and have suggested a general approach which describes a coherently
driven two-level system interacting with a dephasing reservoir. Present
calculations show that the non-Markovian character of the reservoir leads to
the dependence of the dephasing rate on the driving-field intensity, as
observed experimentally. Moreover, we have shown that the damping of Rabi
oscillations might occur as a result of different dephasing mechanisms for both
stationary and non-stationary effects due to coupling to the environment.
Present calculated results are found in quite good agreement with available
experimental measurements
Generation of Superposition States and Charge-Qubit Relaxation Probing in a Circuit
We demonstrate how a superposition of coherent states can be generated for a
microwave field inside a coplanar transmission line coupled to a single
superconducting charge qubit, with the addition of a single classical magnetic
pulse for chirping of the qubit transition frequency. We show how the qubit
dephasing induces decoherence on the field superposition state, and how it can
be probed by the qubit charge detection. The character of the charge qubit
relaxation process itself is imprinted in the field state decoherence profile.Comment: 6 pages, 4 figure
Multimode Hong-Ou-Mandel interference
We consider multimode two-photon interference at a beam splitter by photons
created by spontaneous parametric down-conversion. The resulting interference
pattern is shown to depend upon the transverse spatial symmetry of the pump
beam. In an experiment, we employ the first-order Hermite-Gaussian modes in
order to show that, by manipulating the pump beam, one can control the
resulting two-photon interference behavior. We expect these results to play an
important role in the engineering of quantum states of light for use in quantum
information processing and quantum imaging.Comment: 4 pages, 6 figures, submitted to PR
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