14,547 research outputs found
Modulus stabilization of generalized Randall Sundrum model with bulk scalar field
We study the stabilization of inter-brane spacing modulus of generalized
warped brane models with a nonzero brane cosmological constant. Employing
Goldberger-Wise stabilization prescription of brane world models with a bulk
scalar field, we show that the stabilized value of the modulus generally
depends on the value of the brane cosmological constant. Our result further
reveals that the stabilized modulus value corresponding to a vanishingly small
cosmological constant can only resolve the gauge hierarchy problem
simultaneously. This in turn vindicates the original Randall-Sundrum model
where the 3-brane cosmological constant was chosen to be zero.Comment: 12 Pages, 1 figure, Revtex, Version to appear in Euro. Phys. Let
Brane-worlds and theta-vacua
Reductions from odd to even dimensionalities ( or ), for
which the effective low-energy theory contains chiral fermions, present us with
a mismatch between ultraviolet and infrared anomalies. This applies to both
local (gauge) and global currents; here we consider the latter case. We show
that the mismatch can be explained by taking into account a change in the
spectral asymmetry of the massive modes--an odd-dimensional analog of the
phenomenon described by the Atiyah-Patodi-Singer theorem in even
dimensionalities. The result has phenomenological implications: we present a
scenario in which a QCD-like -angle relaxes to zero on a certain
(possibly, cosmological) timescale, despite the absence of any light axion-like
particle.Comment: 44 pages, 4 figure
Inter-Electrode Capacitances of Triode Valves and their Dependence on the Operating Condition
Photoelastic Method for Stress Analysis
The discovery of photoelastic effect is credited to Sir David Brewster who published in 1816 an account that clear glass when stressed and examined in polarised light exhi-bited coloured patterns. The corresponding theory was deve-loped by Neuman, Maxwell, Wertheim and other noted physic-ists. In the engineering world, this science first appeared around 1900 and was developed mainly by Profe-ssors A. Mesnager, F.G. Coker and L.N.G. Filon, Prof. Coker
made engineering applications of photoelasticity possible mostly through introduction of celluloid for models, repl-acing costly and difficult-to-machine glass models and the use of monochromatic light. Notable among other important workers are Professors F6ppl, Frocht and Neuber. In recent years the development of new synthetic resins possessing desirable photoelastic characteristics, has helped to enlarge applications of the method to a wider variety of problems
The Comparative Influence of Short and Long Range Electric Fields in the Salts of the Iron Group of Elements. Part III
Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistance manganite: La0.7Ce0.3MnO3 film
The electronic structure of La0.7Ce0.3MnO3 (LCeMO) thin film has been
investigated using photoemission spectroscopy (PES) and x-ray absorption
spectroscopy (XAS). The Ce 3d core-level PES and XAS spectra of LCeMO are very
similar to those of CeO2, indicating that Ce ions are far from being trivalent.
A very weak 4f resonance is observed around the Ce 4d 4f absorption edge,
suggesting that the localized Ce 4f states are almost empty in the ground
state. The Mn 2p XAS spectrum reveals the existence of the Mn(2+) multiplet
feature, confirming the Mn(2+)-Mn(3+) mixed-valent states of Mn ions in LCeMO.
The measured Mn 3d PES/XAS spectra for LCeMO agrees reasonably well with the
calculated Mn 3d PDOS using the LSDA+U method. The LSDA+U calculation predicts
a half-metallic ground state for LCeMO.Comment: 7 pages, 7 figure
Experimental Quantification of Entanglement Through Heat Capacity
A new experimental realization of heat capacity as an entanglement witness
(EW) is reported. Entanglement properties of a low dimensional quantum spin
system are investigated by heat capacity measurements performed down to very
low temperatures (400mK), for various applied magnetic field values. The
experimentally extracted results for the value of heat capacity at zero field
matches perfectly with the theoretical estimates of entanglement from model
Hamiltonians. The studied sample is a spin antiferromagnetic
system which shows clear signature of quantum phase transition (QPT) at very
low temperatures when the heat capacity is varied as a function of fields at a
fixed temperature. The variation of entanglement as a function of field is then
explored in the vicinity of the quantum phase transition to capture the sudden
loss of entanglement.Comment: 8 pages, 6 figures, To be published in NJ
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