This paper is based on the study of random lozenge tilings of non-convex polygonal regions with interacting non-convexities (cuts) and the corresponding asymptotic kernel as in [3] and [4] (discrete tacnode kernel). Here this kernel is used to the find the probability distributions and joint probability distributions for the fluctuation of tiles along lines in between the cuts. These distributions are new.
Dedicated to the memory of Ludvig Faddeev1 The discrete tacnode kernel and main result Domino or lozenge tilings of large geometric shapes constitute a rich source of new statistical phenomena: they have sufficient complexity to have interesting features and yet are simple enough to be tractable! Most models studied sofar display two phases, a solid phase with a bricklike pattern, and a liquid phase, for which the correlations decay polynomially with distance. More recently, new models were considered having an additional phase, a gas phase, for which the correlations decay exponentially with distance. This paper will deal with a model having the two phases, solid and liquid.A celebrated example goes back to MacMahon [21] in 1911, who found a simple combinatorial formula for the number of lozenge tilings of a hexagon of sides a, b, c, a, b, c. This model has been widely studied and extended from the macroscopic point of view, but also from the microscopic point of view [8,12,13,7]. For tilings of hexagons, everything is known: when the size gets large, an arctic ellipse, inscribed in the hexagon, separates the liquid phase and the solid phases appearing in the six corners of the hexagon. The liquid phase behaves like a Gaussian Free Field, the statistical fluctuations of the tiles along the ellipse fluctuate according to the Airy process [14]. The tiles in the neighborhood of the tangency points of the arctic ellipse with the hexagon behave as the eigenvalues of the consecutive principal minors of a GUE-matrix (GUE-minor process) [15]. They are all universal distributions, in the sense that they have been found in entirely different circumstances as well. They are also known to occur at critical points along the boundary between phases. The universal distributions are "integrable": many of them relate to known integrable systems, like KdV equation, the Boussinesq equation, Toda lattices, etc... or they can be treated by means of Riemann-Hilbert methods.This paper written in memory of Ludvig Faddeev is a tribute to his pioneering contributions to the integrable field. In 1970-71, he gave a lecture at Rockefeller University in NY on the KdV equation, showing that KdV is a completely integrable Hamiltonian system, and that the map to the spectral data is symplectic. His brilliant lecture triggered the interest and inspiration of one of the authors of this paper (PvM): thank you, Ludvig! Domino tilings of Aztec diamonds have also been extensively studied from the combinatorial point of view and from the microscopic point of view [10,11,18,24,12,14].