Trionic phase of ultracold fermions in an optical lattice: A variational study

Rapp, Akos; Hofstetter, Walter; Zarand, Gergely

Trionic phase of ultracold fermions in an optical lattice: A variational study

Authors

Rapp, Akos

Hofstetter, Walter

Zarand, Gergely

Description

To investigate ultracold fermionic atoms of three internal states (colors) in an optical lattice, subject to strong attractive interaction, we study the attractive three-color Hubbard model in infinite dimensions by using a variational approach. We find a quantum phase transition between a weak-coupling superconducting phase and a strong-coupling trionic phase where groups of three atoms are bound to a composite fermion. We show how the Gutzwiller variational theory can be reformulated in terms of an effective field theory with three-body interactions and how this effective field theory can be solved exactly in infinite dimensions by using the methods of dynamical mean field theory.
14 PRB pages, 8 figures