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Interaction and filling-induced quantum phases of dual Mott insulators of bosons and fermions

Nature Physics volume 7, pages 642–648 (2011)Cite this article

Abstract

Many-body effects are at the very heart of diverse phenomena found in condensed-matter physics. One striking example is the Mott-insulator phase, where conductivity is suppressed as a result of a strong repulsive interaction. Advances in cold-atom physics have led to the realization of the Mott-insulating phases of atoms in an optical lattice, mimicking the corresponding condensed-matter systems. Here, we explore an exotic strongly-correlated system of interacting dual Mott insulators of bosons and fermions. We find that an interspecies interaction between bosons and fermions drastically modifies each of the Mott insulators, causing effects that include melting, generation of composite particles, an anti-correlated phase and complete phase separation. Comparison between the experimental results and numerical simulations indicate intrinsic adiabatic heating and cooling for the attractively and repulsively interacting dual Mott insulators, respectively.

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Figure 1: Schematic illustration of effects of interspecies interaction and filling on dual Mott insulators of bosons and fermions.
Figure 2: Photoassociation and occupancy measurements in an optical lattice.
Figure 3: Occupancy measurements and numerical simulation of occupancy distributions.
Figure 4: Modulation spectroscopy of mixed Mott insulator.
Figure 5: Various types of composite particles in the attractively interacting system.
Figure 6: Thermodynamics of repulsively and attractively interacting dual Mott insulators.

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Acknowledgements

We acknowledge S. Uetake, T. Fukuhara, S. Sugimoto, Y. Takasu and H. Wayama for their experimental help and J. Doyle for careful reading of the manuscript. This work is supported by the Grant-in-Aid for Scientific Research of JSPS (No. 18204035, 21102005C01 (Quantum Cybernetics)), GCOE Program ‘The Next Generation of Physics, Spun from Universality and Emergence’ from MEXT of Japan, and World- Leading Innovative R&D on Science and Technology (FIRST). S.S and S.T. acknowledge support from JSPS.

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Authors and Affiliations

  1. Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan

    Seiji Sugawa, Shintaro Taie, Rekishu Yamazaki & Yoshiro Takahashi

  2. NTT Basic Research Laboratories, NTT Corporation, Atsugi 243-0198, Japan

    Kensuke Inaba & Makoto Yamashita

  3. JST, CREST, Chiyoda-ku, Tokyo 102-0075, Japan

    Kensuke Inaba, Rekishu Yamazaki, Makoto Yamashita & Yoshiro Takahashi

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  1. Seiji Sugawa
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Contributions

S.S., S.T. and R.Y. performed the experiment. K.I. and M.Y. performed the theoretical analysis. Y.T. supervised the whole project. All the authors discussed the results and wrote the manuscript.

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Correspondence to Seiji Sugawa.

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Sugawa, S., Inaba, K., Taie, S. et al. Interaction and filling-induced quantum phases of dual Mott insulators of bosons and fermions. Nature Phys 7, 642–648 (2011). https://doi.org/10.1038/nphys2028

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