|Title||Excitations and correlations in the driven-dissipative Bose-Hubbard model|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Journal||Phys. Rev. A|
|Date Published||APR 4|
|Type of Article||Article|
Using a field-theoretic approach within the Schwinger-Keldysh formalism, we study a Bose-Hubbard model in the presence of a driving field and dissipation due to one-body losses. We recover the bistability diagram from the Gross-Pitaevski equation, and analyze the different phases with respect to their elementary excitations and correlations. We find the low-density solution to be subdivided into a dynamically instable, a gapped, and a gapless regime. The correlations decay exponentially, but a substantial increase of correlation length marks the regime of gapless excitations.