49,214 research outputs found
Fully QED/relativistic theory of light pressure on free electrons by isotropic radiation
Full text linkA relativistic/QED theory of light pressure on electrons by an isotropic, in
particular blackbody radiation predicts thermalization rates of free electrons
over entire span of energies available in the lab and the nature. The
calculations based on the QED Klein-Nishina theory of electron-photon
scattering and relativistic Fokker-Planck equation, show that the transition
from classical (Thompson) to QED (Compton) thermalization determined by the
product of electron energy and radiation temperature, is reachable under
conditions for controlled nuclear fusion, and predicts large acceleration of
electron thermalization in the Compton domain and strong damping of plasma
oscillations at the temperatures near plasma nuclear fusion.Comment: 9 pages, 2 figures. arXiv admin note: substantial text overlap with
arXiv:1410.695
Short-Time Effects on Eigenstate Structure in Sinai Billiards and Related Systems
Full text linkThere is much latitude between the requirements of Schnirelman's theorem
regarding the ergodicity of individual high-energy eigenstates of classically
chaotic systems on the one hand, and the extreme requirements of random matrix
theory on the other. It seems likely that some eigenstate statistics and
long-time transport behavior bear nonrandom imprints of the underlying
classical dynamics while simultaneously obeying Schnirelman's theorem. Indeed
this was shown earlier in the case of systems which approach classical
ergodicity slowly, and is also realized in the scarring of eigenstates, even in
the limit, along unstable periodic orbits and their manifolds.
Here we demonstrate the nonrandom character of eigenstates of Sinai-like
systems. We show that mixing between channels in Sinai systems is dramatically
deficient compared to random matrix theory predictions. The deficit {\it
increases} as for , and is due to the vicinity of
the measure zero set of orbits which never collide with the Sinai obstruction.
Coarse graining to macroscopic scales recovers the Schnirelman result. Three
systems are investigated here: a Sinai-type billiard, a quantum map which
possesses the essential properties of the Sinai billiard, and a unitary map
corresponding to a quasirandom Hamiltonian. Various wavefunction and long-time
transport statistics are defined, theoretically investigated, and compared to
numerical data.Comment: 19 pages, including 13 figures, submitted to Phys Rev
Perturbative, Non-Supersymmetric Completions of the Little Higgs
Full text linkThe little Higgs mechanism produces a light 100 GeV Higgs while raising the
natural cutoff from 1 TeV to 10 TeV. We attempt an iterative little Higgs
mechanism to produce multiple factors of 10 between the cutoff and the 100 GeV
Higgs mass in a perturbative theory. In the renormalizable sector of the
theory, all quantum corrections to the Higgs mass proportional to mass scales
greater than 1 TeV are absent -- this includes quadratically divergent,
log-divergent, and finite loops at all orders. However, even loops proportional
to scales just a factor of 10 above the Higgs (or any other scalar) mass come
with large numerical factors that reintroduce fine-tuning. Top loops, for
example, produce an expansion parameter of not 1/(4 pi) but 1/5. The geometric
increase in the number of fields at higher energies simply exacerbates this
problem. We build a complete two-stage model up to 100 TeV, show that direct
sensitivity of the electroweak scale to the cutoff is erased, and estimate the
tuning due to large numerical factors. We then discuss the possibility, in a
toy model with only scalar and gauge fields, of generating a tower of little
Higgs theories and show that the theory quickly becomes a large-N gauge theory
with ~ N fundamental scalars. We find evidence that at least this toy model
could successfully generate light scalars with an exponentially large cutoff in
the absence of supersymmetry or strong dynamics. The fine-tuning is not
completely eliminated, but evidence suggests that this result is model
dependent. We then speculate as to how one might marry a working tower of
fields of this type at high scales to a realistic theory at the weak scale.Comment: 26 (+1) pages, 9 figure
Weak Quantum Ergodicity
Full text linkWe examine the consequences of classical ergodicity for the localization
properties of individual quantum eigenstates in the classical limit. We note
that the well known Schnirelman result is a weaker form of quantum ergodicity
than the one implied by random matrix theory. This suggests the possibility of
systems with non-gaussian random eigenstates which are nonetheless ergodic in
the sense of Schnirelman and lead to ergodic transport in the classical limit.
These we call "weakly quantum ergodic.'' Indeed for a class of "slow ergodic"
classical systems, it is found that each eigenstate becomes localized to an
ever decreasing fraction of the available state space, in the semiclassical
limit. Nevertheless, each eigenstate in this limit covers phase space evenly on
any classical scale, and long-time transport properties betwen individual
quantum states remain ergodic due to the diffractive effects which dominate
quantum phase space exploration.Comment: 12 pages, 11 figure
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