Synopsis: One relation to rule them all

Data continue to accumulate showing that an important set of universal relations accurately describes the properties of ultracold fermionic gases.
Synopsis figure
Illustration: Alan Stonebraker

Quantum gases of ultracold fermions offer a versatile way to study phenomena from quark matter to superconductors. In 2008, Shina Tan (then at the University of Washington) published a set of exact universal relations connecting microscopic quantities with thermodynamic variables under a wide range of conditions. Recently, a group at JILA experimentally verified some of the Tan relations in ultracold potassium-40 [1]. Writing in Physical Review Letters, Eva Kuhnle and colleagues at Swinburne University of Technology in Melbourne, Australia, now add to the picture with their results on lithium-6.

Kuhnle et al. used Bragg scattering of atoms from a periodic optical potential to verify one of the Tan relations for pair correlations as a function of both the scattering length and probe momentum. This complements the JILA work, which verified a relation between total energy and adiabatic changes in scattering length, and another relation that extends the virial theorem (which expresses total energy in terms of kinetic energy, external potential energy, and interaction energy) to quantum gases. – David Voss

[1] J. T. Stewart, J. P. Gaebler, T. E. Drake, and D. S. Jin, Phys. Rev. Lett. 104, 235301 (2010); see also Viewpoint commentary by D. Sheehy, Physics 3, 48 (2010).


Announcements

More Announcements »

Subject Areas

Atomic and Molecular Physics

Next Synopsis

Nuclear Physics

Order out of chaos

Read More »

Related Articles

Viewpoint: Superfluids Hit the Street
Atomic and Molecular Physics

Viewpoint: Superfluids Hit the Street

A flow pattern dubbed the von Kármán vortex street, which is renowned for its aesthetic beauty and extreme power, has been created in a superfluid. Read More »

Viewpoint: Lamb Shift Spotted in Cold Gases
Atomic and Molecular Physics

Viewpoint: Lamb Shift Spotted in Cold Gases

Cold atomic gases exhibit a phononic analog of the Lamb shift, in which energy levels shift in the presence of the quantum vacuum. Read More »

Synopsis: Quantum Droplets Swell to a Macrodrop
Atomic and Molecular Physics

Synopsis: Quantum Droplets Swell to a Macrodrop

Experiments with ultracold magnetic atoms reveal liquid-like quantum droplets that are 20 times larger than previously observed droplets.    Read More »

More Articles