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).


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular Physics

Next Synopsis

Nuclear Physics

Order out of chaos

Read More »

Related Articles

Synopsis: A Lens to Focus Spins
Quantum Information

Synopsis: A Lens to Focus Spins

A quantum bit stored in the spin excitation of an atomic cloud could be “focused” onto the quantum state of a single atom. Read More »

Synopsis: The Softness of an Atom’s Touch
Atomic and Molecular Physics

Synopsis: The Softness of an Atom’s Touch

Two spectroscopic probes are combined to measure the “softness” of collisions between cold atoms. Read More »

Synopsis: Radioactive Qubits
Atomic and Molecular Physics

Synopsis: Radioactive Qubits

The trapping and cooling of the radioactive isotope barium-133 offers up an attractive system for encoding quantum information. Read More »

More Articles