Synopsis: Fermionic Switch

Interacting atoms mimic the behavior of identical fermions.
Synopsis figure
G. Zürn et al., Phys. Rev. Lett. (2012)

Whether particles in a many-body quantum system are bosons or fermions determines its fundamental properties. For identical fermions, the probability to occupy the same point in space has to vanish. However, simulating the emergence of this effect is challenging, since the fermionic nature of a particle can’t be slowly turned on. Now, a group in Germany has designed a cold-atom experiment where they can adjust the interactions between two distinguishable fermions so they mimic identical fermions.

Gerhard Zürn and his colleagues at Heidelberg University prepared two experiments in which an optical potential confined a pair of fermionic lithium-6 atoms in a long, cigar-shaped volume. In one experiment, the atoms were identical; in the other, the two atoms had opposite spin. The group used an external magnetic field to tune the interaction strength between the distinguishable atoms, but this field had no effect on the identical fermions.

A quirk of this one-dimensional system is that if both two-particle systems have the same energy, they must be described by the same spatial probability distribution. The authors determined the energy of each two-particle system by creating a “leak” in the optical potential and measuring the rate at which a particle tunneled out. By tuning the repulsive interaction between the distinguishable atoms, Zürn et al. were able to bring this system to a point where the probability that the particles overlap is zero, as for two identical fermions.

The ability to simulate the wave function of identical fermions in a two-particle system such as this could eventually allow the study of more complex many-bodied quantum systems. – Jessica Thomas


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsQuantum Physics

Previous Synopsis

Biological Physics

Double, Double…Bubble

Read More »

Next Synopsis

Particles and Fields

Going the Distance

Read More »

Related Articles

Synopsis: Solving Many-Body Problems with a Quantum Microscope
Quantum Physics

Synopsis: Solving Many-Body Problems with a Quantum Microscope

A microscope that images the momenta of atoms in a Bose-Einstein condensate could solve quantum many-body problems. Read More »

Focus: Interferometer for Lighter Atoms
Atomic and Molecular Physics

Focus: Interferometer for Lighter Atoms

A new atom interferometer works at less extreme temperatures and with lighter atoms than previous designs, opening up a new route to precision measurements of fundamental constants. Read More »

Synopsis: Trapping a Rydberg Ion
Quantum Information

Synopsis: Trapping a Rydberg Ion

A trapped ion excited to a hydrogen-like Rydberg state shows promise for qubit applications. Read More »

More Articles