Speaker
Layla Hormozi
(Penn State University)
Description
We study interacting bosons on a lattice in a magnetic field.
When the number of flux quanta per plaquette is close to a
rational fraction, the low energy physics is mapped to a
multi-species continuum model: bosons in the lowest
Landau level where each boson is given an internal degree
of freedom, or pseudospin. We find that the interaction
potential between the bosons involves terms that do not
conserve pseudospin, corresponding to umklapp processes,
which in some cases can also be seen as BCS-type pairing
terms. We argue that in experimentally realistic regimes for
bosonic atoms in optical lattices with synthetic magnetic
fields, these terms are crucial for determining the nature of
allowed ground states. In particular, we show numerically
that certain paired wavefunctions related to the Moore-Read
Pfaffian state are stabilized by these terms, whereas certain
other wavefunctions can be destabilized when umklapp
processes become strong.
