# Many Body Effects of Chiral Edge Fermions - Biao Lian - Princeton

1+1D Chiral Fermions on the edges of 2+1D chiral topological phases are free from backscattering, which lead to quantized Hall and thermal Hall effects. Interacting chiral fermions at low energies are usually believed to form an integrable chiral Luttinger liquid. We study the integrability of N identical chiral Majorana fermion modes with generic 4-fermion interactions. We find the system is integrable by bosonization when N<=6, but becomes quantum chaotic when N>=7. In the large N limit, the system defines a chiral SYK model, which can be solved analytically. The maximal chaos bound is approached when the interaction strength tends to the upper limit, while the zero-temperature entropy density is zero. Lastly, we verify the transition from integrability to chaos at N=7 by level statistics numerical calculations.