title: Tunneling-induced restoration of the degeneracy and the time-reversal symmetry breaking in optical lattices.
abstract: We study the ground-state properties of bosons loaded into the p band of a one-dimensional optical lattice. We show that the phase diagram of the system is substantially affected by the anharmonicity of the lattice potential. In particular, for a certain range of tunneling strength, the full many-body ground state of the system becomes degenerate. In this region, an additional symmetry of the system, namely, the parity of the occupation number of the chosen orbital, is spontaneously broken. The state with a nonvanishing staggered angular momentum, which breaks the time-reversal symmetry, becomes the true ground state of the system.
authors: Institute of Physics of the Polish Academy of Sciences, Aleja Lotników 32/46, PL-02-668 Warsaw, Poland and ICFO, The Institute of Photonic Sciences, Avenue Carl Friedrich Gauss, No. 3, E-08860 Castelldefels (Barcelona), Spain and Center for Theoretical Physics of the Polish Academy of Sciences, Aleja Lotników 32/46, PL-02-668 Warsaw, Poland.
authors: Tomasz
authors: T
authors: Sowiński
authors: Mateusz
authors: M
authors: Łącki
authors: Omjyoti
authors: O
authors: Dutta
authors: Joanna
authors: J
authors: Pietraszewicz
authors: Piotr
authors: P
authors: Sierant
authors: Mariusz
authors: M
authors: Gajda
authors: Jakub
authors: J
authors: Zakrzewski
authors: Maciej
authors: M
authors: Lewenstein