393 research outputs found
Unruh quantization in presence of a condensate
We have shown that the Unruh quantization scheme can be realized in Minkowski
spacetime in the presence of Bose-Einstein condensate containing infinite
average number of particles in the zero boost mode and located basically inside
the light cone. Unlike the case of an empty Minkowski spacetime the condensate
provides the boundary conditions necessary for the Fulling quantization of the
part of the field restricted only to the Rindler wedge of Minkowski spacetime.Comment: 4 page
Limitations on the attainable intensity of high power lasers
It is shown that even a single pair created by a super strong laser
field in vacuum would cause development of an avalanche-like QED cascade which
rapidly depletes the incoming laser pulse. This confirms the old N. Bohr
conjecture that the electric field of the critical QED strength
could never be created.Comment: 4 pages, 3 figure
Anisotropy of Electrons Accelerated by a High-Intensity Laser Pulse
We describe a realistic model for a focused high-intensity laser pulse in
three dimensions. Relativistic dynamics of an electron submitted to such pulse
is described by equations of motion with ponderomotive potential depending on a
single free parameter in the problem, which we refer to as the "asymmetry
parameter". It is shown that the asymmetry parameter can be chosen to provide
quantitative agreement of the developed theory with experimental results of
Malka et al. [Phys. Rev. Lett. 78, 3314 (1997)] who detected angular asymmetry
in the spatial pattern of electrons accelerated in vacuum by a high-intensity
laser pulse
On the existence of black hole evaporation yet again
A new argument is presented confirming the point of view that a Schwarzschild
black hole formed during a collapse process does not radiate
Creation of electron-positron plasma with superstrong laser field
We present a short review of recent progress in studying QED effects of
interaction of ultra-relativistic laser pulses with vacuum and plasma.
The development of laser technologies promises very rapid growth of laser
intensities in close future already. Two exawatt class facilities (ELI and
XCELS, Russia) in Europe are already in the planning stage. Realization of
these projects will make available a laser of intensity W/cm
or even higher. Therefore, discussion of nonlinear optical effects in vacuum
are becoming urgent for experimentalists and are currently gaining much
attention. We show that, in spite of the fact that the respective field
strength is still essentially less than V/cm, the nonlinear vacuum effects will be accessible for observation
at ELI and XCELS facilities. The most promissory for observation is the effect
of pair creation by laser pulse in vacuum. It is shown, that at intensities
W/cm, creation even of a single pair is accompanied by
development of an avalanchelike QED cascade. There exists an important
distinctive feature of the laser-induced cascades, as compared with the air
showers arising due to primary cosmic ray entering the atmosphere. In our case
the laser field plays not only the role of a target (similar to a nucleus in
the case of air showers). It is responsible also for acceleration of slow
particles. It is shown that the effect of pair creation imposes a natural limit
for attainable laser intensity. Apparently, the field strength is
not accessible for pair creating electromagnetic field at all.Comment: To be published in digest "IZEST Scientific Case" in EPJ ST early
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