CQOS PRL paper highlighted in American Physical Society online magazine
In a study published this week in Physical Review Letters, researchers from the Centre for Quantum and Optical Sciences present measurements of Tan's universal contact parameter in a unitary Fermi gas, as a function of the temperature. The contact parameter quantifies the likelihood of finding two atoms at very short distances from each other and is strongly influenced by whether or not the particles have paired up. The pairing of fermions is an essential requirement for superconductivity and superfluidity in collections of fermionic particles but developing a detailed understanding of the pairing process itself is an ongoing challenge. This study utilised Bragg spectroscopy and found that the contact displays a rapid increase when the temperature is cooled below the superfluid transition, suggesting potentially a sudden increase in the fraction of paired atoms happens at the critical temperature.
This paper was published back-to-back in the same issue with a closely related paper by Martin Zwierlein and co-workers from MIT, who found very similar behaviour of the contact using an entirely different measurement scheme.
Both papers were highlighted in Physics, the Americal Physical Society online magazine
Link to paper abstract:
Link to Physics Synopsis
Link to FLEET news release