3 research outputs found
Quantum resonant effects in the delta-kicked rotor revisited
We review the theoretical model and experimental realization of the atom optics
δ-kicked rotor (AOKR), a paradigm of classical and quantum chaos. We
have performed a number of experiments with an all-optical Bose-Einstein condensate (BEC)
in a periodic standing wave potential in an AOKR system. We discuss results of the
investigation of the phenomena of quantum resonances in the AOKR. An interesting feature
of the momentum distribution of the atoms obtained as a result of short pulses of light,
is the variance of the momentum distribution or the kinetic energy
⟨p2⟩/2m in units of the recoil energy
Erec = ħωrec.
The energy of the system is examined as a function of pulse period for a range of kicks
that allow the observation of quantum resonances. In particular we study the behavior of
these resonances for a large number of kicks. Higher order quantum resonant effects
corresponding to the fractional Talbot time of
(1/4)TT and
(1/5)TT for five and ten kicks have been
observed. Moreover, we describe the effect of the initial momentum of the atoms on quantum
resonances in the AOKR
Lokalbehandlung von Spalthautentnahmestellen mit Octenidin®-Gel unter Okklusion - Erste Ergebnisse einer prospektiven, doppelblind randomisierten Multicenterstudie
We report a combined directing effect of the simultaneously applied graphoepitaxy and electric field on the self-assembly of cylinder forming polystyrene-b-poly(dimethylsiloxane) block copolymer in thin films. A correlation length of up to 20 mu m of uniaxial ordered striped patterns is an order of magnitude greater than that produced by either graphoepitaxy or electric field alignment alone and is achieved at reduced annealing times. The angle between the electric field direction and the topographic guides as well as the dimensions of the trenches affected both the quality of the ordering and the direction of the orientation of cylindrical domains: parallel or perpendicular to the topographic features. We quantified the interplay between the electric field and the geometry of the topographic structures by constructing the phase diagram of microdomain orientation. This combined approach allows the fabrication of highly ordered block copolymer structures using macroscopically prepatterned photolithographic substrates
Quantum resonant effects in the delta-kicked rotor revisited
We review the theoretical model and experimental realization of the atom
optics kicked rotor (AOKR), a paradigm of classical and quantum chaos.
We have performed a number of experiments with an all-optical Bose-Einstein
condensate (BEC) in a periodic standing wave potential in an AOKR system. We
discuss results of the investigation of the phenomena of quantum resonances in
the AOKR. An interesting feature of the momentum distribution of the atoms
obtained as a result of short pulses of light, is the variance of the momentum
distribution or the kinetic energy in units of the recoil energy
. The energy of the system is examined as a
function of pulse period for a range of kicks that allow the observation of
quantum resonances. In particular we study the behavior of these resonances for
a large number of kicks. Higher order quantum resonant effects corresponding to
the fractional Talbot time of (1/4) and (1/5) for five and ten
kicks have been observed. Moreover, we describe the effect of the initial
momentum of the atoms on quantum resonances in the AOKR.Comment: 30 pages, 17 figure