Harvard Team Creates a Cold-Atom Fermi–Hubbard Antiferromagnet

May 25, 2017

Img. 1: Probing antiferromagnetism in the Hubbard model with a quantum gas microscope.*

Although high-temperature superconductivity seems like a complicated phenomenon, its basic features are captured by the very simple Fermi–Hubbard model. Researchers have been able to emulate this model using ultracold quantum gases, but to see exciting phenomena based on long-range correlation, such as superconductivity, the system needs to reach extremely low temperatures. In a Letter to Nature*, researchers in Prof. Markus Greiner's group, with assistance from Prof. Eugene Demler, demonstrate a milestone towards these interesting low-temperature phases. They create an antiferromagnet with a correlation length that encompasses the whole system. The foundation for this achievement is a quantum gas microscope developed by the authors. Ultracold quantum gases might soon be able to simulate a Fermi–Hubbard system close to its ground state and help to clarify the mechanism for high-temperature superconductivity.

*See Anton Mazurenko, Christie S. Chiu, Geoffrey Ji, Maxwell F. Parsons, Márton Kanász-Nagy, Richard Schmidt, Fabian Grusdt, Eugene Demler, Daniel Greif & Markus Greiner, "A cold-atom Fermi–Hubbard antiferromagnet," Nature 545 (25 May 2017) DOI: 10.1038/nature22362.

**Also read "Quantum physics: A firmer grip on the Hubbard model" by Giamarchi in Nature "News and Views": Nature 545 (25 May 2017) doi:10.1038/545414a.