3,187 research outputs found
Experimental Implications for a Linear Collider of the SUSY Dark Matter Scenario
This paper presents the detection issues for the lightest slepton
\tilde{\tau}_1 at a future e^+e^- TeV collider given the dark matter
constraints set on the SUSY mass spectrum by the WMAP results. It intends to
illustrate the importance of an optimal detection of energetic electrons in the
very forward region for an efficient rejection of the
\gamma\gamma background. The TESLA parameters have been used in the case of
head-on collisions and in the case of a 10, mrad half crossing angle.Comment: 24 pages, 13 figures, Work presented at the International Conference
on Linear Colliders (LCWS04), 19-23 April 2004, Le Carre des Sciences, Paris,
Franc
Electric circuit networks equivalent to chaotic quantum billiards
We formulate two types of electric RLC resonance network equivalent to
quantum billiards. In the network of inductors grounded by capacitors squared
resonant frequencies are eigenvalues of the quantum billiard. In the network of
capacitors grounded by inductors squared resonant frequencies are given by
inverse eigen values of the billiard. In both cases local voltages play role of
the wave function of the quantum billiard. However as different from quantum
billiards there is a heat power because of resistance of the inductors. In the
equivalent chaotic billiards we derive the distribution of the heat power which
well describes numerical statistics.Comment: 9 pages, 7 figure
Timing performance of 30-nm-wide superconducting nanowire avalanche photodetectors
We investigated the timing jitter of superconducting nanowire avalanche
photodetectors (SNAPs, also referred to as cascade switching superconducting
single photon detectors) based on 30-nm-wide nanowires. At bias currents (IB)
near the switching current, SNAPs showed sub 35 ps FWHM Gaussian jitter similar
to standard 100 nm wide superconducting nanowire single-photon detectors. At
lower values of IB, the instrument response function (IRF) of the detectors
became wider, more asymmetric, and shifted to longer time delays. We could
reproduce the experimentally observed IRF time-shift in simulations based on an
electrothermal model, and explain the effect with a simple physical picture
Pumped quantum systems: immersion fluids of the future?
Quantum optical techniques may yield immersion fluids with high indices of
refraction without absorption. We describe one such technique in which a probe
field experiences a large index of refraction with amplification rather than
absorption, and examine its practicality for an immersion lithography
application. Enhanced index can be observed in a three-level system with a
tunable, near-resonant, coherent probe and incoherent pump field that inverts
population of the probe transition. This observation contradicts the common
belief that large indices of refraction are impossible without absorption,
however it is well in accord with existing electromagnetic theory and practice.
Calculations show that a refractive index >> 2 is possible with practical
experimental parameters. A scheme with an incoherent mixture of pumped and
unpumped atoms is also examined, and is seen to have a lower refractive index
(~2) accompanied by neither gain nor loss.Comment: 6 pages, 7 figures, accepted for publication in J. Vac. Sci. Tech. B,
Nov/Dec 2005 (full reference not known yet
Dark Matter with (very) heavy SUSY scalars at ILC
In this paper, six SUSY scenarios with heavy sfermions, mainly based on
theoretical arguments and on experimental indications for new physics, are
defined. These scenarios, consistent with the amount of dark matter (DM)
measured by WMAP, are then analysed in detail providing pertinent examples of
the potential of ILC. It is shown that in most cases ILC, with its high
precision based on the chargino analysis and in spite of an incomplete coverage
of the gaugino and slepton mass spectrum, can predict the amount of DM in our
universe with an accuracy which matches the WMAP results.Comment: Work presented at the International Collider Physics and Detector
Workshop Snowmass, Colorado, August 14-27, 200
Distribution of nearest distances between nodal points for the Berry function in two dimensions
According to Berry a wave-chaotic state may be viewed as a superposition of
monochromatic plane waves with random phases and amplitudes. Here we consider
the distribution of nodal points associated with this state. Using the property
that both the real and imaginary parts of the wave function are random Gaussian
fields we analyze the correlation function and densities of the nodal points.
Using two approaches (the Poisson and Bernoulli) we derive the distribution of
nearest neighbor separations. Furthermore the distribution functions for nodal
points with specific chirality are found. Comparison is made with results from
from numerical calculations for the Berry wave function.Comment: 11 pages, 7 figure
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