Exact short-time height distribution in 1D KPZ equation with Brownian initial condition

Abstract

The early time regime of the Kardar-Parisi-Zhang (KPZ) equation in $1+1$ dimension, starting from a Brownian initial condition with a drift $w$, is studied using the exact Fredholm determinant representation. For large drift we recover the exact results for the droplet initial condition, whereas a vanishingly small drift describes the stationary KPZ case, recently studied by weak noise theory (WNT). We show that for short time $t$, the probability distribution $P(H,t)$ of the height $H$ at a given point takes the large deviation form $P(H,t)\sim \exp \left(-\Phi (H)/\sqrt{t}\right)$. We obtain the exact expressions for the rate function $\Phi (H)$ for $H<H_{c2}$. Our exact expression for $H_{c2}$ numerically coincides with the value at which WNT was found to exhibit a spontaneous reflection symmetry breaking. We propose two continuations for $H>H_{c2}$, which apparently correspond to the symmetric and asymmetric WNT solutions. The rate function $\Phi (H)$ is Gaussian in the center, while it has asymmetric tails, $|H{|}^{5/2}$ on the negative $H$ side and $H^{3/2}$ on the positive $H$ side.

29 pages, 7 figures

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Cited by in corpus (4)

• Height distribution tails in the Kardar-Parisi-Zhang equation with Brownian initial conditions
• Large fluctuations of a Kardar-Parisi-Zhang interface on a half-line: the height statistics at a shifted point
• Time-averaged height distribution of the Kardar-Parisi-Zhang interface
• Exact short-time height distribution and dynamical phase transition in the relaxation of a Kardar-Parisi-Zhang interface with random initial condition