21,798 research outputs found
Spherical collapse of a heat conducting fluid in higher dimensions without horizon
We consider a scenario where the interior spacetime,described by a heat
conducting fluid sphere is matched to a Vaidya metric in higher
dimensions.Interestingly we get a class of solutions, where following heat
radiation the boundary surface collapses without the appearance of an event
horizon at any stage and this happens with reasonable properties of matter
field.The non-occurrence of a horizon is due to the fact that the rate of mass
loss exactly counterbalanced by the fall of boundary radius.Evidently this
poses a counter example to the so-called cosmic censorship hypothesis.Two
explicit examples of this class of solutions are also given and it is observed
that the rate of collapse is delayed with the introduction of extra
dimensions.The work extends to higher dimensions our previous investigation in
4D.Comment: 6 page
Minimum consumptions requirements: theoretical and quantitative implications for growth and distribution
The authors study the impact of a minimum consumption requirement on the rate of economic growth and the evolution of wealth distribution. The requirement introduces a positive dependence between the intertemporal elasticity of substitution and household wealth. This dependence implies a transition phase during which the growth rate of per-capita quantities rise toward their steady-state values and the distributions of wealth, consumption, and permanent income become more unequal. The authors calibrate the minimum consumption requirement to match estimates available for a sample of Indian villagers and find that these transitional effects are quantitatively significant and depend importantly on the economy's steady-state growth rate. NOTE: This paper refers to figures not currently available with this electronic version. For a hard copy of the figures, call the Research Department's Publications Desk at 215-574-6428 and ask for Working Paper 97-15.Consumption (Economics) ; Wealth
T-matrix formulation of real-space dynamical mean-field theory and the Friedel sum rule for correlated lattice fermions
We formulate real-space dynamical mean-field theory within scattering theory.
Thereby the Friedel sum rule is derived for interacting lattice fermions at
zero temperature.Comment: 7 pages, no figures, extended and corrected versio
Kinetic market models with single commodity having price fluctuations
We study here numerically the behavior of an ideal gas like model of markets
having only one non-consumable commodity. We investigate the behavior of the
steady-state distributions of money, commodity and total wealth, as the
dynamics of trading or exchange of money and commodity proceeds, with local (in
time) fluctuations in the price of the commodity. These distributions are
studied in markets with agents having uniform and random saving factors. The
self-organizing features in money distribution are similar to the cases without
any commodity (or with consumable commodities), while the commodity
distribution shows an exponential decay. The wealth distribution shows
interesting behavior: Gamma like distribution for uniform saving propensity and
has the same power-law tail, as that of the money distribution, for a market
with agents having random saving propensity.Comment: RevTeX4, 6 pages, 5 eps figures, accepted in Eur. Phys. J.
Kalb-Ramond field interactions in a braneworld scenario
Electromagnetic and (linearized) gravitational interactions of the
Kalb-Ramond (KR) field, derived from an underlying ten dimensional heterotic
string in the zero slope limit, are studied in a five dimensional background
Randall-Sundrum I spacetime with standard model fields confined to the visible
brane having negative tension. The warp factor responsible for generating the
gauge hierarchy in the Higgs sector is seen to appear inverted in the KR field
couplings, when reduced to four dimensions. This leads to dramatically enhanced
rotation, {\it far beyond observational bounds}, of the polarization plane of
electromagnetic and gravitational waves, when scattered by a homogeneous KR
background. Possible reasons for the conflict between theory and observation
are discussed.Comment: 13 pages Latex, no figures, discussion and acknowledgements adde
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