Stochastic Laplacian growth

Abstract

A point source on a plane constantly emits particles which rapidly diffuse and then stick to a growing cluster. The growth probability of a cluster is presented as a sum over all possible scenarios leading to the same final shape. The classical point for the action, defined as a minus logarithm of the growth probability, describes the most probable scenario and reproduces the Laplacian growth equation, which embraces numerous fundamental free boundary dynamics in non-equilibrium physics. For non-classical scenarios we introduce virtual point sources, in which presence the action becomes the Kullback-Leibler entropy. Strikingly, this entropy is shown to be the sum of electrostatic energies of layers grown per elementary time unit. Hence the growth probability of the presented non-equilibrium process obeys the Gibbs-Boltzmann statistics, which, as a rule, is not applied out from equilibrium. Each layer's probability is expressed as a product of simple factors in an auxiliary complex plane after a properly chosen conformal map. The action at this plane is a sum of Robin functions, which solve the Liouville equation. At the end we establish connections of our theory with the tau-function of the integrable Toda hierarchy and with the Liouville theory for non-critical quantum strings.

6 pages; v2: exposition improved, 2 figures added

References in corpus (1)

• Random Matrices in 2D, Laplacian Growth and Operator Theory

Cited by in corpus (5)

• Statistical mechanics of stochastic growth phenomena
• Quantized Laplacian growth, III: On conformal field theories of Laplacian growth
• Quantized Laplacian growth, II: 1D hydrodynamics of the Loewner density
• Integrability-preserving regularizations of Laplacian Growth
• Martingales of stochastic Laplacian growth