Theorie Kolloquium | October 11, 16:30

Temperature Interfaces in the Katz-Lebowitz-Spohn Driven Lattice Gas

Uwe Täuber

We explore the intriguing spatial patterns that emerge in a two-dimensional
spatially inhomogeneous Katz-Lebowitz-Spohn (KLS) driven lattice gas with
attractive nearest-neighbor interactions. The domain is split into two
regions with hopping rates governed by different temperatures T > T_c and
T_c, respectively, where T_c indicates the critical temperature for phase
ordering, and with the temperature boundaries oriented perpendicular to the
drive. In the hotter region, the system behaves like the (totally) asymmetric
exclusion processes (TASEP), and experiences particle blockage in front of
the interface to the critical region. To explain this particle density
accumulation near the interface, we have measured the steady-state current in
the KLS model at T > T_c and found it to decay as 1/T. In analogy with TASEP
systems containing "slow" bonds, transport in the high-temperature subsystem
is impeded by the lower current in the cooler region, which tends to set the
global stationary particle current value. This blockage is induced by the
extended particle clusters, growing logarithmically with system size, in the
critical region. We observe the density profiles in both high-and low-
temperature subsystems to be similar to the well-characterized coexistence
and maximal-current phases in (T)ASEP models with open boundary conditions,
which are respectively governed by hyperbolic and trigonometric tangent
functions. Yet if the lower temperature is set to T_c, we detect marked
fluctuation corrections to the mean-field density profiles, e.g., the
corresponding critical KLS power law density decay near the interfaces into
the cooler region. If the temperature interface is aligned parallel to the
drive, we observe the cooler region to act as an absorbing sink for particle
transport, with blockages emerging at the subsystem boundaries.


Virginia Tech
Seminar Room 0.03, ETP
Contact: Sebastian Diehl