2,579 research outputs found
Atmospheric muon background in the ANTARES detector
An evaluation of the background due to atmospheric muons in the ANTARES high
energy neutrino telescope is presented. Two different codes for atmospheric
shower simulation have been used. Results from comparisons between these codes
at sea level and detector level are presented. The first results on the
capability of ANTARES to reject this class of background are given.Comment: 4 pages, 4 figures, To appear in Proceedings of the 29th
International Cosmic Ray Conference (ICRC 2005), Pune, India, 3 - 10 Aug 200
Nonlinear dissipation can combat linear loss
We demonstrate that it is possible to compensate for effects of strong linear
loss when generating non-classical states by engineered nonlinear dissipation.
We show that it is always possible to construct such a loss-resistant
dissipative gadget in which, for a certain class of initial states, the desired
non-classical pure state can be attained within a particular time interval with
an arbitrary precision. Further we demonstrate that an arbitrarily large linear
loss can still be compensated by a sufficiently strong coherent or even thermal
driving, thus attaining a strongly non-classical (in particular,
sub-Poissonian) stationary mixed states.Comment: Submitted to PR
Quantum tight-binding chains with dissipative coupling
We present a one-dimensional tight-binding chain of two-level systems coupled
only through common dissipative Markovian reservoirs. This quantum chain can
demonstrate anomalous thermodynamic behavior contradicting Fourier law.
Population dynamics of individual systems of the chain is polynomial with the
order determined by the initial state of the chain. The chain can simulate
classically hard problems, such as multi-dimensional random walks
Quantum techniques using continuous variables of light
We present schemes for the generation and evaluation of continuous variable
entanglement of bright optical beams and give a brief overview of the variety
of optical techniques and quantum communication applications on this basis. A
new entanglement-based quantum interferometry scheme with bright beams is
suggested. The performance of the presented schemes is independent of the
relative interference phase which is advantageous for quantum communication
applications.Comment: 11 pages, 5 figures; minor correction, accepted versio
Polarization squeezing of intense pulses with a fiber Sagnac interferometer
We report on the generation of polarization squeezing of intense, short light
pulses using an asymmetric fiber Sagnac interferometer. The Kerr nonlinearity
of the fiber is exploited to produce independent amplitude squeezed pulses. The
polarization squeezing properties of spatially overlapped amplitude squeezed
and coherent states are discussed. The experimental results for a single
amplitude squeezed beam are compared to the case of two phase-matched,
spatially overlapped amplitude squeezed pulses. For the latter, noise variances
of -3.4dB below shot noise in the S0 and the S1 and of -2.8dB in the S2 Stokes
parameters were observed, which is comparable to the input squeezing magnitude.
Polarization squeezing, that is squeezing relative to a corresponding
polarization minimum uncertainty state, was generated in S1.Comment: v4: 2 small typos corrected v3: misc problems with Tex surmounted -
mysteriously missing text returned to results - vol# for Korolkova et al. PRA
v2: was a spelling change in author lis
Weak Values and Continuous-Variable Entanglement Concentration
We demonstrate a general weak measurement model which allows Gaussian
preserving entanglement concentration of the two mode squeezed vacuum. The
power of this simple and elegant protocol is through the constraints it places
on possible ancilla states and measurement strategies that will allow
entanglement concentration. In particular, it is shown how previously
discovered protocols of this kind emerge as special examples of the general
model described here. Finally, as evidence of its utility, we use it to provide
another novel example of such a protocol.Comment: 4 pages, 1 figure, Final version to appear in Phys. Rev.
A pulsed source of continuous variable polarization entanglement
We have experimentally demonstrated polarization entanglement using
continuous variables in an ultra-short pulsed laser system at telecommunication
wavelengths. Exploiting the Kerr-nonlinearity of a glass fibre we generated a
polarization squeezed pulse with S2 the only non-zero Stokes parameter thus S1
and S3 being the conjugate pair. Polarization entanglement was generated by
interference of the polarization squeezed field with a vacuum on a 50:50 beam
splitter. The two resultant beams exhibit strong quantum noise correlations in
S1 and S3. The sum noise signal of S3 was at the respective shot noise level
and the difference noise signal of S1 fell 2.9dB below this value
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