Rugsėjo 25 dieną 11 val. 432 kamb. Ian Spielman (Nacionalinis standartų ir technologijų institutas, JAV) skaitys pranešimą "Zitterbewegung in a degenerate quantum gas: observed"

Kviečiame dalyvauti!

Abstract:
Among the earliest predictions of relativistic quantum mechanics is Schrodinger's suggestion that a relativistic quantum particle, such as an electron, should undergo a microscopic trembling -- Zitterbewegung -- is it moves.   For the electron, the  $f = m c^2 / h approx 1times10^ {rm Hz}$ frequency and $delta x = h / m capprox 2 {rm pm} $ amplitude of this motion is below any foreseeable threshold for detection.  This desperate situation can be happily resolved by working with artificial relativistic systems such as graphene, or as here with ultracold atoms where $c$ can be vastly decreased and where the mass  $m$ is tunable.  In our experiment, where $capprox 6 {rm mm}/{rm s}$, $fsim 1 {rm kHz}$ and $delta x sim 0.5 mu{rm m}$, Zitterbewegung is easily observed.

In this talk, I will present our observation of Zitterbewegung in a spin-orbit coupled Bose-Einstein condensate.  We directly measure the frequency and amplitude of this microscopic motion, and find it to be in agreement with our relativistic model.