35,859 research outputs found
Jean-Paul Sartre: Mystical Atheist or Mystical Antipathist?
Jean-Paul Sartre is rarely discussed in the philosophy of religion. In 2009, however, Jerome Gellman broke the silence, publishing an article in which he argued that the source of Sartreās atheism was neither philosophical nor existential, but mystical. Drawing from several of Sartreās works ā including Being and Nothingness, Words, and a 1943 review entitled āA New Mysticā ā I argue that there are strong biographical and philosophical reasons to disagree with Gellmanās conclusion that Sartre was a āmystical atheistā. Moreover, I question the likelihood of drawing any deļ¬nitive conclusions regarding the sources of Sartreās ambiguous atheism
Electronic Transport at Low Temperatures: Diagrammatic Approach
We prove that a diagrammatic evaluation of the Kubo formula for the
electronic transport conductivity due the exchange of bosonic excitations, in
the usual conserving ladder approximation, yields a result consistent with the
Boltzmann equation. In particular, we show that an uncontrolled approximation
that has been used to solve the integral equation for the vertex function is
unnecessary. An exact solution of the integral equation yields the same
asymptotic low-temperature behavior as the approximate one, albeit with a
different prefactor, and agrees with the temperature dependence of the
Boltzmann solution. Examples considered are electron scattering from acoustic
phonons, and from helimagnons in helimagnets.Comment: Submitted to Physics E (FMQT08 Proceedings). Requires Elsevier style
file (included
Rigorous derivation of the Landau equation in the weak coupling limit
We examine a family of microscopic models of plasmas, with a parameter
comparing the typical distance between collisions to the strength of
the grazing collisions. These microscopic models converge in distribution, in
the weak coupling limit, to a velocity diffusion described by the linear Landau
equation (also known as the Fokker-Planck equation). The present work extends
and unifies previous results that handled the extremes of the parameter
, for the whole range (0, 1/2], by showing that clusters of overlapping
obstacles are negligible in the limit. Additionally, we study the diffusion
coefficient of the Landau equation and show it to be independent of the
parameter.Comment: 22 pages, 8 figures, accepted to Communications in Pure and Applied
Analysi
Analytical approach to relaxation dynamics of condensed Bose gases
The temporal evolution of a perturbation of the equilibrium distribution of a
condensed Bose gas is investigated using the kinetic equation which describes
collision between condensate and noncondensate atoms. The dynamics is studied
in the low momentum limit where an analytical treatment is feasible. Explicit
results are given for the behavior at large times in different temperature
regimes.Comment: 25 pages, 3 figures. Typos corrected. Final version to appear in
Annals of Physic
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