86 research outputs found
Collective Two-Atom Effects and Trapping States in the Micromaser
We investigate signals of trapping states in the micromaser system in terms
of the average number of cavity photons as well as a suitably defined
correlation length of atoms leaving the cavity. In the description of
collective two-atom effects we allow the mean number of pump atoms inside the
cavity during the characteristic atomic cavity transit time to be as large as
of order one. The master equation we consider, which describes the micromaser
including collective two-atom effects, still exhibits trapping states for even
for a mean number of atoms inside the cavity close to one. We, however, argue
more importantly that the trapping states are more pronounced in terms of the
correlation length as compared to the average number of cavity photons, i.e. we
suggest that trapping states can be more clearly revealed experimentally in
terms of the atom correlation length. For axion detection in the micromaser
this observable may therefore be an essential ingredient.Comment: 5 figure
Noise and Order in Cavity Quantum Electrodynamics
In this paper we investigate the various aspects of noise and order in the
micromaser system. In particular, we study the effect of adding fluctuations to
the atom cavity transit time or to the atom-photon frequency detuning. By
including such noise-producing mechanisms we study the probability and the
joint probability for excited atoms to leave the cavity. The influence of such
fluctuations on the phase structure of the micromaser as well as on the
long-time atom correlation length is also discussed. We also derive the
asymptotic form of micromaser observables.Comment: 31 pages and 8 figure
On the Preparation of Pure States in Resonant Microcavities
We consider the time evolution of the radiation field (R) and a two-level
atom (A) in a resonant microcavity in terms of the Jaynes-Cummings model with
an initial general pure quantum state for the radiation field. It is then
shown, using the Cauchy-Schwarz inequality and also a Poisson resummation
technique, that {\it perfect} coherence of the atom can in general never be
achieved. The atom and the radiation field are, however, to a good
approximation in a pure state in the middle of what
has been traditionally called the ``collapse region'', independent of the
initial state of the atoms, provided that the initial pure state of the
radiation field has a photon number probability distribution which is
sufficiently peaked and phase differences that do not vary significantly around
this peak. An approximative analytic expression for the quantity
\Tr[\rho^2_{A}(t)], where is the reduced density matrix for the
atom, is derived. We also show that under quite general circumstances an
initial entangled pure state will be disentangled to the pure state .Comment: 14 pages and 3 figure
Theory of the Microscopic Maser Phase Transitions
Phase diagrams of the micromaser system are mapped out in terms of the physical parameters at hand like the atom cavity transit time, the atom-photon frequency detuning, the number of thermal photons and the probability for a pump atom to be in its excited state. Critical fluctuations are studied in terms of correlation measurements on atoms having passed through the micromaser or on the microcavity photons themselves. At sufficiently large values of the detuning we find a ``twinkling'' mode of the micromaser system. Detailed properties of the trapping states are also presented
On Collective Effects in Cavity Quantum Electrodynamics
We investigate the role of collective effects in the micromaser system as
used in various studies of the physics of cavity electrodynamics. We focus our
attention on the effect on large-time correlations due to multi-atom
interactions. The influence of detection efficiencies and collective effects on
the appearance of trapping states at low temperatures is also found to be of
particular importance.Comment: 10 pages, 7 figures, 36 reference
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