Quantum Physics: Interactions Propel a Magnetic Dance

June 22, 2017

Figure 1: Strongly interacting atoms in a gauge field.*
[Reprinted by permission from Macmillan Publishers Ltd: Nature ©2017.]

Particle interactions have a defining role in many properties of materials, but are often difficult to incorporate into a theoretical framework. Although theories that omit these interactions can describe some behaviours, a full understanding of a material can come only from a complete account of the system, including its interactions. Interaction-based phenomena such as magnetism are poorly understood at the microscopic level, and so the ability to study them using the bottom-up approaches offered by ultracold quantum gas experiments holds considerable promise. [In a Letter to Nature*, Ming Eric Tai, Alexander Lukin, Matthew Rispoli, and other members of Prof. Markus Greiner's lab] report such an experiment in which pairs of atoms exhibit chiral motion — movement that has a particular 'handedness' — only as a result of the system's interactions. The work is an early step towards the simulation of non-trivial many-body quantum systems, which will allow exotic condensed-matter phenomena to be studied.

Tai and colleagues combine, for the first time, two of the most valuable tools for studying ultracold quantum gases. One is the quantum gas microscope, which can be used to image the individual sites of an optical lattice (an array of interfering laser beams used to trap a quantum gas). The other is an artificial (effective) magnetic field, which causes the neutral atoms in such experiments to behave like charged particles in a real magnetic field...

Continue reading "Quantum physics: Interactions propel a magnetic dance" by Lindsay J. LeBlanc, Nature 546 (22 June 2017) doi:10.1038/546481a.

Also see the original Letter:
*M.E. Tai, A. Lukin, M. Rispoli, R. Schittko, T. Menke, D. Borgnia, P.M. Preiss, Fabian Grusdt, Adam M. Kaufman & Markus Greiner, "Microscopy of the interacting Harper–Hofstadter model in the two-body limit," Nature 546 (22 June 2017) doi:10.1038/nature22811.