Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.

February 2 , 2006
12:30 PM

Krzysztof Sacha,
Jagellonian University, Poland

N-particle Bogoliubov vacuum state

Abstract

he Bogoliubov vacuum state in the number-conserving Bogoliubov theory will be considered. It will be shown that in the particle representation the vacuum can be written in a simple diagonal form. The vacuum state can describe the stationary N-particle ground state of a condensate in a trap, but it can also represent a dynamical state when, for example, a Bose-Einstein condensate initially prepared in the stationary ground state is subject to a time-dependent perturbation. Comparison of N-body states obtained within the Bogoliubov theory with the exact ground states of model systems will be presented. In the talk there will be also shown an analysis of experimental parameters where, despite of small average number of atoms depleted from a condensate, quantum many-body effects lead to measurable fluctuations of condensate density.