Spinfull bosons in an optical lattice

S. L. Rolston

Sumiran Pujari, Christopher L. Henley

What kind of lattice Hamiltonian manifestly has an ordered state with spontaneous orbital currents? We consider interacting spinless fermions on an array of square plaquettes, connected by weak hopping; the array geometry may be a $2\ifmmode\times\else\texttimes\fi{}2L$ ladder, a $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}2L$ ``tube,'' or a $2L\ifmmode\times\else\texttimes\fi{}2L$ square grid. At half filling, we derive an effective Hamiltonian in terms of pseudospins, of which one component represents orbital currents, and find the conditions sufficient for orbital current long-range order. We consider spinfull variants of the aforesaid spinless models and make contact with other spinfull models in the literature purported to possess spontaneous currents.

C. Moseley, O. Fialko, K. Ziegler

Hidetoshi Katori, Masao Takamoto, Tomoya Akatsuka

We report on frequency comparison of two optical lattice clocks based on fermionic 87Sr trapped in 1D optical lattice and bosonic 88Sr in 3D one. We discuss that these two lattice clock configurations would optimize the lattice clocks' performance from the view point of the quantum statistical properties of interrogated atoms and optical lattice geometries. The frequency comparison of two optical clocks offers an important step to investigate the lattice clocks' uncertainty less than 10-15, where no working standard exists.

Hidetoshi Katori, Masao Takamoto, Tomoya Akatsuka +1 more

We discuss configurations of optical lattice clocks from the viewpoint of lattice geometries and quantum statistics of interrogated atoms. This leads to two promising schemes; one-dimensional lattice loaded with spin-polarized fermions and three-dimensional lattice loaded with bosons. These two optical lattice clocks based on fermionic87Sr and bosonic88Sr were demonstrated by measuring the frequency stability as well as their isotope shift. In addition, we address our ongoing experimental challenges for optical lattice clocks.

Daniel S. Goldbaum, Erich J. Mueller