Temperature measurements of a Bose--Einstein condensate by ultra--intense light pulses

TL;DR

This paper proposes a novel method for measuring the temperature of a Bose--Einstein condensate using ultra--intense light pulses and nonlinear optical materials, aiming for more accurate results near the condensation temperature.

Contribution

It introduces a new experimental technique for temperature measurement in Bose--Einstein condensates based on time-of-flight differences detected by nonlinear optics.

Findings

Proposed a method using ultra--intense light pulses for temperature measurement.

Calculated expected temperature values using Bose--Einstein distribution.

Compared experimental and theoretical temperature measurements.

Abstract

Experimentally the temperature in a Bose--Einstein condensate is always deduced resorting to the comparison between the Maxwell--Boltzmann velocity distribution function and the density profile in momentum space. Though a successful method it is an approximation, since it also implies the use of classical statistical mechanics at temperatures close to the condensation temperature where quantal effects play a relevant role. The present work puts forward a new method in which we use an ultra--intense light pulse and a nonlinear optical material as detectors for differences in times--of--flight. This experimental value shall be compared against the result here calculated, using the Bose--Einstein distribution function, which is a temperature--dependent variable, and in this way the temperature of the condensate is obtained.