Off-site trimer superfluid on a one-dimensional optical lattice

What is it about?

The Bose–Hubbard model with an effective off-site three-body tunneling, characterized by jumps towards one another, between one atom on a site and a pair atoms on the neighborhood site, is studied systematically on a one-dimensional (1D) lattice, by using the density matrix renormalization group method. The off-site trimer superfluid, condensing at momentum k = 0, emerges in the softcore Bose–Hubbard model but it disappears in the hardcore Bose–Hubbard model. Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from [ Phys. Rev. A 81, 011601(R) (2010)] is stable in the thermodynamic limit. The off-site trimer superfluid phase, the partially off-site trimer superfluid phase and the Mott insulator phase are found, as well as interesting phase transitions, such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase. Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.

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Photo by Ling Tang on Unsplash

Photo by Ling Tang on Unsplash

Why is it important?

The new results in this work concerning the OTSF and POTSF phases are helpful in realizing and understanding the novel phases by cold atom experiments. This work confirms and extends previous work using the mean field Bose-Hubbard model, which is an effective nonlinear field theory.

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