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

Focus: Strong Light Reflection from Few Atoms
Optics

Focus: Strong Light Reflection from Few Atoms

Up to 75% of light reflects from just 2000 atoms aligned along an optical fiber, an arrangement that could be useful in photonic circuits. Read More »

Viewpoint: Ionization Delays That Stand Out
Optics

Viewpoint: Ionization Delays That Stand Out

Attosecond-resolution experiments have determined the delay in an electron’s emission from a molecule after being ionized with light. Read More »

Focus: Giant Molecule Made from Two Atoms
Atomic and Molecular Physics

Focus: Giant Molecule Made from Two Atoms

Experiments confirm the existence of 1-micrometer-sized molecules made of two cesium atoms by showing that their binding energies agree with predictions.   Read More »

More Articles