2,803 research outputs found
Trapped atoms in cavity QED: coupling quantized light and matter
On the occasion of the hundredth anniversary of Albert Einstein's annus mirabilis, we reflect on the development and current state of research in cavity quantum electrodynamics in the optical domain. Cavity QED is a field which undeniably traces its origins to Einstein's seminal work on the statistical theory of light and the nature of its quantized interaction with matter. In this paper, we emphasize the development of techniques for the confinement of atoms strongly coupled to high-finesse resonators and the experiments which these techniques enable
Cavity QED with Single Atoms and Photons
Recent experimental advances in the field of cavity quantum electrodynamics (QED) have opened new possibilities for control of atom-photon interactions. A laser with "one and the same atom" demonstrates the theory of laser operation pressed to its conceptual limit. The generation of single photons on demand and the realization of cavity QED with well defined atomic numbers N = 0, 1, 2,... both represent important steps toward realizing diverse protocols in quantum information science. Coherent manipulation of the atomic state via Raman transitions provides a new tool in cavity QED for in situ monitoring and control of the atom-cavity system. All of these achievements share a common point of departure: the regime of strong coupling. It is thus interesting to consider briefly the history of the strong coupling criterion in cavity QED and to trace out the path that research has taken in the pursuit of this goal
Optical pumping via incoherent Raman transitions
A new optical pumping scheme is presented that uses incoherent Raman
transitions to prepare a trapped Cesium atom in a specific Zeeman state within
the 6S_{1/2}, F=3 hyperfine manifold. An important advantage of this scheme
over existing optical pumping schemes is that the atom can be prepared in any
of the F=3 Zeeman states. We demonstrate the scheme in the context of cavity
quantum electrodynamics, but the technique is equally applicable to a wide
variety of atomic systems with hyperfine ground-state structure.Comment: 8 pages, 4 figure
Cooling to the Ground State of Axial Motion for One Atom Strongly Coupled to an Optical Cavity
Localization to the ground state of axial motion is demonstrated for a
single, trapped atom strongly coupled to the field of a high finesse optical
resonator. The axial atomic motion is cooled by way of coherent Raman
transitions on the red vibrational sideband. An efficient state detection
scheme enabled by strong coupling in cavity QED is used to record the Raman
spectrum, from which the state of atomic motion is inferred. We find that the
lowest vibrational level of the axial potential with zero-point energy 13uK is
occupied with probability P0~0.95.Comment: 5 pages, 4 figure
Observation of the Vacuum-Rabi Spectrum for One Trapped Atom
The transmission spectrum for one atom strongly coupled to the field of a
high-finesse optical resonator is observed to exhibit a clearly resolved
vacuum-Rabi splitting characteristic of the normal modes in the eigenvalue
spectrum of the atom-cavity system. A new Raman scheme for cooling atomic
motion along the cavity axis enables a complete spectrum to be recorded for an
individual atom trapped within the cavity mode, in contrast to all previous
measurements in cavity QED that have required averaging over many atoms.Comment: 5 pages with 4 figure
Priming Effects on Commitment to Help and on Real Helping Behavior
Years of research on bystander apathy have demonstrated that the physical presence of
others can reduce the tendency to help individuals needing assistance. Recent research
on the implicit bystander effect has suggested that simply imagining the presence of
others can lead to less helping behavior on a subsequent unrelated task. The present
study was designed to contribute to previous findings on the implicit bystander effect
by demonstrating these effects on commitment to help and on real helping behavior,
rather than simply on intentions to help. Studies 1a and 1b demonstrate that merely
priming participants with the construct of being in a group at Time 1 created significantly
less commitment to future helping on a subsequent task at Time 2. Study 2 aimed
to extend this effect to behavioral measures and verified that participants exposed to a
group prime helped less than those who were exposed to a single-person prime. The
implications of these findings for the literature on the bystander effect are discussed
The AF structure of non commutative toroidal Z/4Z orbifolds
For any irrational theta and rational number p/q such that q|qtheta-p|<1, a
projection e of trace q|qtheta-p| is constructed in the the irrational rotation
algebra A_theta that is invariant under the Fourier transform. (The latter is
the order four automorphism U mapped to V, V mapped to U^{-1}, where U, V are
the canonical unitaries generating A_theta.) Further, the projection e is
approximately central, the cut down algebra eA_theta e contains a Fourier
invariant q x q matrix algebra whose unit is e, and the cut downs eUe, eVe are
approximately inside the matrix algebra. (In particular, there are Fourier
invariant projections of trace k|qtheta-p| for k=1,...,q.) It is also shown
that for all theta the crossed product A_theta rtimes Z_4 satisfies the
Universal Coefficient Theorem. (Z_4 := Z/4Z.) As a consequence, using the
Classification Theorem of G. Elliott and G. Gong for AH-algebras, a theorem of
M. Rieffel, and by recent results of H. Lin, we show that A_theta rtimes Z_4 is
an AF-algebra for all irrational theta in a dense G_delta.Comment: 35 page
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