25,021 research outputs found
Thermodynamic Geometry of the Born-Infeld-anti-de Sitter black holes
Thermodynamic geometry is applied to the Born-Infeld-anti-de Sitter black
hole (BIAdS) in the four dimensions, which is a nonlinear generalization of the
Reissner-Norstr\"Aom-AdS black hole (RNAdS). We compute the Weinhold as well as
the Ruppeiner scalar curvature and find that the singular points are not the
same with the ones obtained using the heat capacity. Legendre-invariant metric
proposed by Quevedo and the metric obtained by using the free energy as the
thermodynamic potential are obtained and the corresponding scalar curvatures
diverge at the Davies points.Comment: Latex,19 pages,14 figure
Asymmetric dark matter and the Sun
Cold dark matter particles with an intrinsic matter-antimatter asymmetry do
not annihilate after gravitational capture by the Sun and can affect its
interior structure. The rate of capture is exponentially enhanced when such
particles have self-interactions of the right order to explain structure
formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural
candidate and has the required relic abundance if its asymmetry is similar to
that of ordinary baryons. We show that such particles can solve the `solar
composition problem'. The predicted small decrease in the low energy neutrino
fluxes may be measurable by the Borexino and SNO+ experiments.Comment: 4 pages, 3 figures (RevTex); Capture rate corrected to obey the
geometrical bound; Changes in adopted cross-sections and particle physics
motivation; Conclusions concerning helioseismology and solar neutrino fluxes
unchange
Quantum Phase Transition in Coupled Superconducting Quantum Dots Array with Charge Frustration
We present the quantum phase transition in two capacitively coupled arrays of
superconducting quantum dots (SQD). We consider the presence of gate voltage in
each superconducting island. We show explicitly that the co-tunneling process
involves with two coupled SQD arrays, near the maximum charge frustration line
is not sufficient to explain the correct quantum phases with physically
consistent phase boundaries. We consider another extra co-tunneling process
along each chain to explain the correct quantum phases with physically
consistent phase boundaries. There is no evidence of supersolid phase in our
study. We use Bethe-ansatz and Abelian bosonization method to solve the problemComment: pages 4 +, comments are welcom
Quantum Logic Processor: A Mach Zehnder Interferometer based Approach
Quantum Logic Processors can be implemented with Mach Zehnder
Interferometer(MZI) configurations for the Quantum logic operations and gates.
In this paper, its implementation for both optical and electronic system has
been presented. The correspondence between Jones matrices for photon
polarizations and Pauli spin matrices for electrons gives a representation of
all the unitary matrices for the quantum gate operations. A novel quantum
computation system based on a Electronic Mach Zehnder Interferometer(MZI) has
also been proposed. It uses the electron spin as the primary qubit. Rashba
effect is used to create Unitary transforms on spin qubits. A mesoscopic Stern
Gerlach apparatus can be used for both spin injection and detection. An
intertwined nanowire design is used for the MZI. The system can implement all
single and double qubit gates. It can easily be coupled to form an array. Thus
the Quantum Logic Processor (QLP) can be built using the system as its
prototype.Comment: 19 pages, 6 figures, 8 Table
Geometric scaling in ultrahigh energy neutrinos and nonlinear perturbative QCD
The ultrahigh energy neutrino cross section is a crucial ingredient in the
calculation of the event rate in high energy neutrino telescopes. Currently
there are several approaches which predict different behaviors for its
magnitude for ultrahigh energies. In this contribution is presented a summary
of current predictions based on the non-linear QCD evolution equations, the
so-called perturbative saturation physics. In particular, predictions are shown
based on the parton saturation approaches and the consequences of geometric
scaling property at high energies are discussed. The scaling property allows an
analytical computation of the neutrino scattering on nucleon/nucleus at high
energies, providing a theoretical parameterization.Comment: 6 pages, one figure. Presented at First Caribbean Symposium on
Nuclear and Astroparticle Physics - STARS2011, La Habana, Cuba, 2011. arXiv
admin note: substantial text overlap with arXiv:1011.2718 by different
author
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