Mainz 2017 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 40: Poster: Quantum Optics and Photonics II

Q 40.14: Poster

Mittwoch, 8. März 2017, 17:00–19:00, P OG2

Exploring Quantum Antiferromagnets with single-site resolution — •Daniel Greif, Anton Mazurenko, Christie S. Chiu, Geoffrey Ji, Maxwell F. Parsons, and Markus Greiner — Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

Strongly correlated electron systems are at the center of many poorly understood phenomena in condensed matter systems, including high-temperature superconductivity, which is thought to be well described by the Hubbard model. Ultracold fermionic atoms trapped in a 2D layer of a square lattice provide a clean and tunable implementation of the Hubbard model. Optical microscopy on these systems permits an unprecedented degree of control and detection unavailable in traditional condensed matter systems. We report site-resolved measurements of strongly interacting many-body states, including 2D fermionic Mott insulators and band insulators. We further report site-resolved measurements of the spin correlation function in these samples, exhibiting antiferromagnetic correlations. High fidelity addressing with a digital micromirror device permits exploration of previously inaccessible regions of the Hubbard model at temperatures below the 3D Neel transition temperature. We detect the presence of antiferromagnetic long-range order at temperatures T/t=0.25 directly from a peak in the spin structure factor, corresponding to a finite staggered magnetization, and a diverging correlation length of the spin correlation function. Our results open the path for a controlled study of the low-temperature phase diagram of the Hubbard model.