  In net-neutral systems correlations between charge fluctuations generate
strong attractive thermal Casimir forces and engineering these forces to
optimize nanodevice performance is an important challenge. We show how the
normal and lateral thermal Casimir forces between two plates containing
Brownian charges can be modulated by decorrelating the system through the
application of an electric field, which generates a nonequilibrium steady state
with a constant current in one or both plates, reducing the ensuing
fluctuation-generated normal force while at the same time generating a lateral
drag force. This hypothesis is confirmed by detailed numerical simulations as
well as an analytical approach based on stochastic density functional theory.

Statistical Mechanics;Mesoscale and Nanoscale Physics;Soft Condensed Matter;Chemical Physics