Exact Large Deviation Functional of a Stationary Open Driven Diffusive System: The Asymmetric Exclusion Process
Abstract
We consider the asymmetric exclusion process (ASEP) in one dimension on sites $i = 1,..., N$, in contact at sites $i=1$ and $i=N$ with infinite particle reservoirs at densities $\rho_a$ and $\rho_b$. As $\rho_a$ and $\rho_b$ are varied, the typical macroscopic steady state density profile $\bar \rho(x)$, $x\in[a,b]$, obtained in the limit $N=L(ba)\to\infty$, exhibits shocks and phase transitions. Here we derive an exact asymptotic expression for the probability of observing an arbitrary macroscopic profile $\rho(x)$: $P_N(\{\rho(x)\})\sim\exp[L{\cal F}_{[a,b]}(\{\rho(x)\});\rho_a,\rho_b]$, so that ${\cal F}$ is the large deviation functional, a quantity similar to the free energy of equilibrium systems. We find, as in the symmetric, purely diffusive case $q=1$ (treated in an earlier work), that $\cal F$ is in general a nonlocal functional of $\rho(x)$. Unlike the symmetric case, however, the asymmetric case exhibits ranges of the parameters for which ${\cal F}(\{\rho(x)\})$ is not convex and others for which ${\cal F}(\{\rho(x)\})$ has discontinuities in its second derivatives at $\rho(x) = \bar{\rho}(x)$; the fluctuations near $\bar{\rho}(x)$ are then nonGaussian and cannot be calculated from the large deviation function.
 Publication:

arXiv eprints
 Pub Date:
 May 2002
 arXiv:
 arXiv:condmat/0205353
 Bibcode:
 2002cond.mat..5353D
 Keywords:

 Condensed Matter  Statistical Mechanics
 EPrint:
 Latex, one PicTeX figure in a separate file