Phase transition in the spanning-hyperforest model on complete hypergraphs

TL;DR

This paper investigates the phase transition in the spanning-hyperforest model on complete hypergraphs using a novel Grassmann formulation, revealing a second-order transition linked to supersymmetry breaking.

Contribution

It introduces a Grassmann-based approach to analyze phase transitions in hypergraph models and characterizes the transition as second order with supersymmetry considerations.

Findings

Identifies the critical point where a giant hyperforest emerges.

Shows the phase transition is second order and related to supersymmetry breaking.

Analyzes the critical behavior via saddle point coalescence.

Abstract

By using our novel Grassmann formulation we study the phase transition of the spanning-hyperforest model of the k-uniform complete hypergraph for any k>= 2. The case k=2 reduces to the spanning-forest model on the complete graph. Different k are studied at once by using a microcanonical ensemble in which the number of hyperforests is fixed. The low-temperature phase is characterized by the appearance of a giant hyperforest. The phase transition occurs when the number of hyperforests is a fraction (k-1)/k of the total number of vertices. The behaviour at criticality is also studied by means of the coalescence of two saddle points. As the Grassmann formulation exhibits a global supersymmetry we show that the phase transition is second order and is associated to supersymmetry breaking and we explore the pure thermodynamical phase at low temperature by introducing an explicit breaking field.