187 research outputs found
Non-equilibrium coherence dynamics of a soft boson lattice
We study the non-equilibrium evolution of the phase coherence of a
Bose-Einstein condensate (BEC) in a one dimensional optical lattice, as the
lattice is suddenly quenched from an insulating to a superfluid state. We
observe slowly damped phase coherence oscillations in the regime of large
filling factor (~100 bosons per site) at a frequency proportional to the
generalized Josephson frequency. The truncated Wigner approximation (TWA)
predicts the frequency of the observed oscillations.Comment: 10 pages. 4 figure
How to measure the wave-function absolute squared of a moving particle by using mirrors
We consider a slow particle with wave function , moving
freely in some direction. A mirror is briefly switched on around a time and
its position is scanned. It is shown that the measured reflection probability
then allows the determination of . Experimentally
available atomic mirrors should make this method applicable to the
center-of-mass wave function of atoms with velocities in the cm/s range.Comment: 4 pages, 5 figure
A spatially and temporally localized sub-laser-cycle electron source
We present an experimental and numerical study of electron emission from a
sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This
process is non-linear in the laser electric field, and the non-linearity can be
tuned via the DC voltage applied to the tip. Numerical simulations of this
system show that electron emission takes place within less than one optical
period of the exciting laser pulse, so that an 8 fsec 800 nm laser pulse is
capable of producing a single electron pulse of less than 1 fsec duration.
Furthermore, we find that the carrier-envelope phase dependence of the emission
process is smaller than 0.1% for an 8 fsec pulse but is steeply increasing with
decreasing laser pulse duration.Comment: 4 pages, 5 figure
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