50 research outputs found
What is the reference frame of an accelerated observer?
The general construction of extended refrence frames for noninertial
observers in flat space is studied. It is shown that, if the observer moves
inertially before and after an arbitrary acceleration and rotation, the region
where reference frames can coincide with an inertial system is bounded for
final velocities exceeding 0.6 c.Comment: 5 pages, 2 figures, published in Phys. Lett. A 215, 1 (1996
Spontaneous emission of polaritons from a Bose-Einstein condensate
We study the spontaneous emission of a partially excited Bose-Einstein
condensate composed of two-level atoms. The formation of polaritons induced by
the ground-state part of the condensate leads to an avoided crossing in the
photon spectrum. This avoided crossing acts similarly to a photonic band gap
and modifies the spontaneous emission rate.Comment: 4 pages, 2 figures, revte