5,559 research outputs found
Fluorescence interferometry
We describe an interferometer based on fluorescent emission of radiation of
two qubits in quasi-one-dimensional modes. Such a system can be readily
realized with dipole emitters near conducting surface-plasmonic nanowires or
with superconducting qubits coupled to coplanar waveguide transmission lines.Comment: 7 pages, 2 figure
Lorentz Invariance Violation and the Observed Spectrum of Ultrahigh Energy Cosmic Rays
There has been much interest in possible violations of Lorentz invariance,
particularly motivated by quantum gravity theories. It has been suggested that
a small amount of Lorentz invariance violation (LIV) could turn off photomeson
interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the
cosmic background radiation and thereby eliminate the resulting sharp
steepening in the spectrum of the highest energy CRs predicted by Greisen
Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported
by the HiRes and Auger collaborations, however, indicate the presence of the
GZK effect. We present the results of a detailed calculation of the
modification of the UHECR spectrum caused by LIV using the formalism of Coleman
and Glashow. We then compare these results with the experimental UHECR data
from Auger and HiRes. Based on these data, we find a best fit amount of LIV of
,consistent with an upper limit of . This possible amount of LIV can lead to a recovery of the cosmic ray
spectrum at higher energies than presently observed. Such an LIV recovery
effect can be tested observationally using future detectors.Comment: corrected proof version to be published in Astroparticle Physic
On mechanisms that enforce complementarity
In a recent publication Luis and Sanchez-Soto arrive at the conclusion that
complementarity is universally enforced by random classical phase kicks. We
disagree. One could just as well argue that quantum entanglement is the
universal mechanism. Both claims of universality are unjustified, however.Comment: 4 page
Quantum entanglement between two magnon modes via Kerr nonlinearity
We propose a scheme to entangle two magnon modes via Kerr nonlinear effect
when driving the systems far-from-equilibrium. We consider two macroscopic
yttrium iron garnets (YIGs) interacting with a single-mode microcavity through
the magnetic dipole coupling. The Kittel mode describing the collective
excitations of large number of spins are excited through driving cavity with a
strong microwave field. We demonstrate how the Kerr nonlineraity creates the
entangled quantum states between the two macroscopic ferromagnetic samples,
when the microcavity is strongly driven by a blue-detuned microwave field. Such
quantum entanglement survives at the steady state. Our work offers new insights
and guidance to designate the experiments for observing the entanglement in
massive ferromagnetic materials. It can also find broad applications in
macroscopic quantum effects and magnetic spintronics.Comment: 6 pages, 3 figure
Collapsible reflector Patent
Self erecting parabolic reflector design for use in spac
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