1,056 research outputs found
Phase space tweezers for tailoring cavity fields by quantum Zeno dynamics
We discuss an implementation of Quantum Zeno Dynamics in a Cavity Quantum
Electrodynamics experiment. By performing repeated unitary operations on atoms
coupled to the field, we restrict the field evolution in chosen subspaces of
the total Hilbert space. This procedure leads to promising methods for
tailoring non-classical states. We propose to realize `tweezers' picking a
coherent field at a point in phase space and moving it towards an arbitrary
final position without affecting other non-overlapping coherent components.
These effects could be observed with a state-of-the-art apparatus
Reply to 'Comment on "Detuning effects in the one-photon mazer" '
We refute in this Reply the criticisms made by M. Abdel-Aty [Phys. Rev. A 70,
047801 (2004)]. We show that none of them are founded and we demonstrate very
explicitly what is wrong in the arguments developed by this author.Comment: 5 pages, 2 figure
Generating and Revealing a Quantum Superposition of Electromagnetic Field Binomial States in a Cavity
We introduce the -photon quantum superposition of two orthogonal
generalized binomial states of electromagnetic field. We then propose, using
resonant atom-cavity interactions, non-conditional schemes to generate and
reveal such a quantum superposition for the two-photon case in a single-mode
high- cavity. We finally discuss the implementation of the proposed schemes.Comment: 4 pages, 3 figures. Title changed (published version
Mesoscopic ensembles of polar bosons in triple-well potentials
Mesoscopic dipolar Bose gases in triple-well potentials offer a minimal
system for the analysis of the long-range character of the dipole-dipole
interactions. We show that this long-range character may be clearly revealed by
a variety of possible ground-state phases. In addition, an appropriate control
of short-range and dipolar interactions may lead to novel scenarios for the
dynamics of atoms and polar molecules in lattices, including the dynamical
creation of mesoscopic Schr\"odinger cats, which may be employed as a source of
highly-nonclassical states for Heisenberg-limited interferometry.Comment: 4 pages, 3 figures. Identical to the published version, including
supplemental material (4 pages, 6 figures)
Continuous monitoring can improve indistinguishability of a single-photon source
A new engineering technique using continuous quantum measurement in
conjunction with feed-forward is proposed to improve indistinguishability of a
single-photon source. The technique involves continuous monitoring of the state
of the emitter, processing the noisy output signal with a simple linear
estimation algorithm, and feed forward to control a variable delay at the
output. In the weak coupling regime, the information gained by monitoring the
state of the emitter is used to reduce the time uncertainty inherent in photon
emission from the source, which improves the indistinguishability of the
emitted photons.Comment: 4 pages, 4 figure
Response of the Strongly-Driven Jaynes-Cummings Oscillator
We analyze the Jaynes-Cummings model of quantum optics, in the
strong-dispersive regime. In the bad cavity limit and on timescales short
compared to the atomic coherence time, the dynamics are those of a nonlinear
oscillator. A steady-state non-perturbative semiclassical analysis exhibits a
finite region of bistability delimited by a pair of critical points, unlike the
usual dispersive bistability from a Kerr nonlinearity. This analysis explains
our quantum trajectory simulations that show qualitative agreement with recent
experiments from the field of circuit quantum electrodynamics.Comment: 5 pages, 3 figure
Qubit-oscillator system under ultrastrong coupling and extreme driving
We introduce an approach to studying a driven qubit-oscillator system in the
ultrastrong coupling regime, where the ratio between coupling
strength and oscillator frequency approaches unity or goes beyond, and
simultaneously for driving strengths much bigger than the qubit energy
splitting (extreme driving). Both qubit-oscillator coupling and external
driving lead to a dressing of the qubit tunneling matrix element of different
nature: the former can be used to suppress selectively certain oscillator modes
in the spectrum, while the latter can bring the qubit's dynamics to a
standstill at short times (coherent destruction of tunneling) even in the case
of ultrastrong coupling.Comment: 4+ pages, 5 figures (published version
Fermionic collective excitations in a lattice gas of Rydberg atoms
We investigate the many-body quantum states of a laser-driven gas of Rydberg
atoms confined to a large spacing ring lattice. If the laser driving is much
stronger than the van-der-Waals interaction among the Rydberg sates, these
many-body states are collective fermionic excitations. The first excited state
is a spin-wave that extends over the entire lattice. We demonstrate that our
system permits to study fermions in the presence of disorder although no
external atomic motion takes place. We analyze how this disorder influences the
excitation properties of the fermionic states. Our work shows a route towards
the creation of complex many-particle states with atoms in lattices
Raman-assisted Rabi resonances in two-mode cavity QED
The dynamics of a vibronic system in a lossy two-mode cavity is studied, with
the first mode being resonant to the electronic transition and the second one
being nearly resonant due to Raman transitions. We derive analytical solutions
for the dynamics of this system. For a properly chosen detuning of the second
mode from the exact Raman resonance, we obtain conditions that are closely
related to the phenomenon of Rabi resonance as it is well known in laser
physics. Such resonances can be observed in the spontaneous emission spectra,
where the spectrum of the second mode in the case of weak Raman coupling is
enhanced substantially.Comment: 6 pages, 5 figure
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
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