Bose-Einstein condensation in random directed networks

Abstract

We consider the phenomenon of Bose-Einstein condensation in a random growing directed net- work. The network grows by the addition of vertices and edges. At each time step the network gains a vertex with probabilty p and an edge with probability 1 − p. The new vertex has a fitness (a, b) with probability f(a, b). A vertex with fitness (a, b), in-degree i and out-degree j gains a new incoming edge with rate a(i + 1) and an outgoing edge with rate b(j + 1). The Bose-Einstein condensation occurs as a function of fitness distribution f(a, b).