157 research outputs found
Quantum teleportation with pair-coherent states
Recently it has been argued that all presently performed continuous variable
quantum teleportation experiments could be explained using a local hidden
variable theory. In this paper we study a modification of the original protocol
which requires a fully quantum mechanical explanation even when coherent states
are teleported. Our calculations of the fidelity of teleportation using a
pair-coherent state under ideal conditions suggests that fidelity above the
required limit of 1/2 may be achievable in an experiment also.Comment: Based on talks at the QIP workshop in 6th Joint Conference on
Mathematics and Computer Science, Pecs, 12-15 July 2006; and Quantum 2006 -
Workshop ad memoriam Carlo Novero, Turin. v2: Added reference to give credit
to L. Vaidma
Extreme sub-wavelength atom localization via coherent population trapping
We demonstrate an atom localization scheme based on monitoring of the atomic
coherences. We consider atomic transitions in a Lambda configuration where the
control field is a standing wave field. The probe field and the control field
produce coherence between the two ground states. We show that this coherence
has the same fringe pattern as produced by a Fabry-Perot interferometer and
thus measurement of the atomic coherence would localize the atom. Interestingly
enough the role of the cavity finesse is played by the ratio of the intensities
of the pump and probe. This is in fact the reason for obtaining extreme
subwavelenth localization. We suggest several methods to monitor the produced
localization.Comment: 6 pages, 5 figure
Strong coupling induced splitting of dynamical response of the optical parametric oscillator
A new quantum regime of the optical parametric oscillator is reported. The strong coupling between the single photon pump mode and the signal-idler modes leads to splitting of the transmission resonance of a cavity containing an optical parametric oscillator. The characteristics of the transmission doublet are obtained
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