Quick search Find article
Quick search
Find article
Deutsche Physikalische Gessellschaft IOP Institute of Physics

A primary noise thermometer for ultracold Bose gases

Focus on Cold Atoms in Optical Lattices

R Gati1, J Esteve, B Hemmerling, T B Ottenstein, J Appmeier, A Weller and M K Oberthaler

Show affiliations


Part of Focus on Cold Atoms in Optical Lattices

We discuss in detail the experimental investigation of thermally induced fluctuations of the relative phase between two weakly coupled Bose–Einstein condensates (BECs). In analogy to superconducting Josephson junctions, the weak coupling originates from a tunnelling process through a potential barrier which is obtained by trapping the condensates in an optical double-well potential. The observed fluctuations of the relative phase are in quantitative agreement with a many body two mode model at finite temperature. The agreement demonstrates the possibility of using the phase fluctuation measurements in a bosonic Josephson junction (BJJ) as a primary thermometer. This new method allows for measuring temperatures far below the critical temperature where standard methods based on time of flight measurements fail. We employ this new thermometer to probe the heat capacity of a degenerate Bose gas as a function of temperature.


PACS

03.75.Lm Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices and topological excitations

05.70.Ce Thermodynamic functions and equations of state

05.40.Ca Noise

05.30.Jp Boson systems

Subjects

Quantum gases, liquids and solids

Statistical physics and nonlinear systems

Dates

Issue 9 (September 2006)

Received 9 June 2006

Published 12 September 2006



View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.