2,871 research outputs found
Continuous Generation of Quantum Light from a Single Ground-State Atom in an Optical Cavity
We show an optical wave-mixing scheme that generates quantum light by means
of a single three-level atom. The atom couples to an optical cavity and two
laser fields that together drive a cycling current within the atom. Weak
driving in combination with strong atom-cavity coupling induces transitions
between the dark states of the system, accompanied by single-photon emission
and suppression of atomic excitation by quantum interference. For strong
driving, the system can generate coherent or Schr\"odinger cat-like fields with
frequencies distinct from those of the applied lasers.Comment: 5 pages, 4 figure
Bilinear and quadratic Hamiltonians in two-mode cavity quantum electrodynamics
In this work we show how to engineer bilinear and quadratic Hamiltonians in
cavity quantum electrodynamics (QED) through the interaction of a single driven
two-level atom with cavity modes. The validity of the engineered Hamiltonians
is numerically analyzed even considering the effects of both dissipative
mechanisms, the cavity field and the atom. The present scheme can be used, in
both optical and microwave regimes, for quantum state preparation, the
implementation of quantum logical operations, and fundamental tests of quantum
theory.Comment: 11 pages, 3 figure
Nonadiabatic coherent evolution of two-level systems under spontaneous decay
In this paper we extend current perspectives in engineering reservoirs by
producing a time-dependent master equation leading to a nonstationary
superposition equilibrium state that can be nonadiabatically controlled by the
system-reservoir parameters. Working with an ion trapped inside a nonindeal
cavity we first engineer effective Hamiltonians that couple the electronic
states of the ion with the cavity mode. Subsequently, two classes of
decoherence-free evolution of the superposition of the ground and decaying
excited levels are achieved: those with time-dependent azimuthal or polar
angle. As an application, we generalise the purpose of an earlier study [Phys.
Rev. Lett. 96, 150403 (2006)], showing how to observe the geometric phases
acquired by the protected nonstationary states even under a nonadiabatic
evolution.Comment: 5 pages, no figure
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