8,641 research outputs found
Heavy Flavour Physics at the LHC
A summary of results in heavy flavour physics from Run 1 of the LHC is
presented. Topics discussed include spectroscopy, mixing, CP violation and rare
decays of charmed and beauty hadrons.Comment: 25 pages, 9 figures (total 17 subfigures). Invited review for Comptes
Rendus de Physique de l'Academie des Science
Free Your Mind: Contemporary Racial Attitudes and Post Racial Theory
The inauguration of the United States first Black President has prompted mass discussions of race relations in America. It is often articulated that America is now in a post-racial society. However, the question still remains: does the election of a Black president demonstrate that America is now a color-blind society? To answer this question, we rely on data collected by PEW (2007). Our results suggest that white and African Americans differ significantly in the extent to which they express post-racial attitudes. Specifically, we find that whites more commonly express post-racial attitudes, claiming that racism and discrimination are rare, in opposition to African American views. On the other hand, blacks are more likely to believe that discrimination still occurs. We further find that whites\u27 post-racial beliefs are significant determinants of their attitudes towards race-related policies, such as affirmative action. Keywords: Race, Obama, Post-racial, Public Opinion, Racial Attitudes, Racial Politics, African American
Universal Dephasing Control During Quantum Computation
Dephasing is a ubiquitous phenomenon that leads to the loss of coherence in
quantum systems and the corruption of quantum information. We present a
universal dynamical control approach to combat dephasing during all stages of
quantum computation, namely, storage, single- and two-qubit operators. We show
that (a) tailoring multi-frequency gate pulses to the dephasing dynamics can
increase fidelity; (b) cross-dephasing, introduced by entanglement, can be
eliminated by appropriate control fields; (c) counter-intuitively and contrary
to previous schemes, one can increase the gate duration, while simultaneously
increasing the total gate fidelity.Comment: 4 pages,3 figure
Signatures of Strong Momentum Localization via Translational-Internal Entanglement
We show that atoms or molecules subject to fields that couple their internal
and translational (momentum) states may undergo a crossover from randomization
(diffusion) to strong localization (sharpening) of their momentum distribution.
The predicted crossover should be manifest by a drastic change of the
interference pattern as a function of the coupling fields.Comment: 4 pages, 3 figure
Physics at SuperB
Flavour will play a crucial role in understanding physics beyond the Standard
Model. Progress in developing a future programme to investigate this central
area of particle physics has recently passed a milestone, with the completion
of the conceptual design report for SuperB, a very high luminosity, asymmetric
e+e- collider. This article summarizes the important role of SuperB in
understanding new physics in the LHC era.Comment: 4 pages, 2 figures. To appear in the proceedings of the International
Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester,
England, 19-25 July 200
Control of multiatom entanglement in a cavity
We propose a general formalism for analytical description of multiatomic
ensembles interacting with a single mode quantized cavity field under the
assumption that most atoms remain un-excited on average. By combining the
obtained formalism with the nilpotent technique for the description of
multipartite entanglement we are able to overview in a unified fashion
different probabilistic control scenarios of entanglement among atoms or
examine atomic ensembles. We then apply the proposed control schemes to the
creation of multiatom states useful for quantum information.Comment: 11 pages, 1 figure. Finalized versio
Detection of non-Gaussian Fluctuations in a Quantum Point Contact
An experimental study of current fluctuations through a tunable transmission
barrier, a quantum point contact, are reported. We measure the probability
distribution function of transmitted charge with precision sufficient to
extract the first three cumulants. To obtain the intrinsic quantities,
corresponding to voltage-biased barrier, we employ a procedure that accounts
for the response of the external circuit and the amplifier. The third cumulant,
obtained with a high precision, is found to agree with the prediction for the
statistics of transport in the non-Poissonian regime.Comment: 4 pages, 4 figures; published versio
Translational Entanglement of Dipole-Dipole Interacting Atoms in Optical Lattices
We propose and investigate a realization of the position- and
momentum-correlated Einstein-Podolsky-Rosen (EPR) states [Phys. Rev. 47, 777
(1935)] that have hitherto eluded detection. The realization involves atom
pairs that are confined to adjacent sites of two mutually shifted optical
lattices and are entangled via laser-induced dipole-dipole interactions. The
EPR "paradox" with translational variables is then modified by
lattice-diffraction effects, and can be verified to a high degree of accuracy
in this scheme.Comment: 4 pages, 3 figures, to be published in PR
Observation of the rare decay B+ -> K+π0π0 and measurement of the quasi-two-body contributions B+ -> K*(892)+π0, B+ -> f0(980)K+, and B+ -> χc0K+
We report an analysis of charmless hadronic decays of charged B mesons to the final state K(+) pi(0)pi(0), using a data sample of (470.9 +/- 2.8) x 10(6) B (B) over bar events collected with the BABAR detector at the Y(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be B(B(+) -> K(+) pi(0)pi(0)) = (16.2 +/- 1.2 +/- 1.5) x 10(-6) and A(CP)(B(+) -> K(+) pi(0)pi(0)) = -0.06 +/- 0.06 +/- 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B(+) -> K*(892)(+) pi(0), B(+) -> f(0)(980)K(+), and B(+) -> chi(c0)K(+) quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B(+) -> K(+) pi(0)pi(0) and B(+) -> K(+)(892)(+) pi(0) channels
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