18,233 research outputs found
Complementarity and Phase Distributions for Angular Momentum Systems
Interferences in the distributions of complementary variables for angular
momentum - two level systems are discussed. A quantum phase distribution is
introduced for angular momentum. Explicit results for the phase distributions
and the number distributions for atomic coherent states, squeezed states and
superpositions of coherent states are given. These results clearly demonstrate
the issue of complementarity and provide us with results analogous to those for
the radiation field.Comment: 9 pages, 3 figures available on request, replaced with minor typos
corrected in abstract, to appear in Physics Letters
Mesoscopic Superposition of States with Sub-Planck Structures in Phase Space
We propose a method using the dispersive interaction between atoms and a high
quality cavity to realize the mesoscopic superposition of coherent states which
would exhibit sub-Planck structures in phase space. In particular we focus on a
superposition involving four coherent states. We show interesting interferences
in the conditional measurements involving two atoms.Comment: 4-page 3-figur
Magneto-optical rotation of spectrally impure fields and its nonlinear dependence on optical density
We calculate magneto-optical rptation of spectrally impure fileds in an
optically thick cold atmic medium. We show that the spectral impurity leads to
non-linear dependence of the rotation angle on optical density. Using our
calculations, we provide a quanttative analysis of the recent experimental
results of G. Labeyrie et al. [Phys. Rev. A 64, 033402 (2001)] using cold
Rb atoms.Comment: 6 pages, 5 Figures, ReVTeX4, Submitted to PR
Vacuum induced Stark shifts for quantum logic using a collective system in a high quality dispersive cavity
A collective system of atoms in a high quality cavity can be described by a
nonlinear interaction which arises due to the Lamb shift of the energy levels
due to the cavity vacuum [Agarwal et al., Phys. Rev. A 56, 2249 (1997)]. We
show how this collective interaction can be used to perform quantum logic. In
particular we produce schemes to realize CNOT gates not only for two-qubit but
also for three-qubit systems. We also discuss realizations of Toffoli gates.
Our effective Hamiltonian is also realized in other systems such as trapped
ions or magnetic molecules
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