Description
Low-lying Dirac modes become localized at the finite-temperature
transition in QCD and other gauge theories, indicating a connection
between localization and deconfinement. This phenomenon can be
understood through the "sea/islands" picture: in the deconfined phase,
modes become trapped on "islands" of Polyakov loop fluctuations within
a "sea" of ordered Polyakov loops.
To test the universality of the "sea/islands" mechanism, we
investigate whether changes in the localization properties of low
modes occur across other thermal transitions where the Polyakov loop
becomes ordered, beyond the usual deconfinement transition. The
fixed-length SU(2)-Higgs model serves as an appropriate model for this
study. After mapping out the phase diagram, we find that low Dirac
modes become localized in the deconfined and Higgs phases, where the
Polyakov loop is ordered. However, localization is absent in the
confined phase. These findings confirm the "sea/islands" picture.
