Abstract
We present quantum Monte Carlo simulations for the chiral Heisenberg Gross-Neveu-Yukawa quantum phase transition of relativistic fermions with Dirac spinor components subject to a repulsive, local four fermion interaction in . Here we employ a two-dimensional lattice Hamiltonian with a single, spin-degenerate Dirac cone, which exactly reproduces a linear energy-momentum relation for all finite size lattice momenta in the absence of interactions. This allows us to significantly reduce finite size corrections compared to the widely studied honeycomb and -flux lattices. A Hubbard term dynamically generates a mass beyond a critical coupling of as the system acquires antiferromagnetic order and SU(2) spin rotational symmetry is spontaneously broken. At the quantum phase transition, we extract a self-consistent set of critical exponents , , , and . We provide evidence for the continuous degradation of the quasiparticle weight of the fermionic excitations as the critical point is approached from the semimetallic phase. Finally, we study the effective “speed of light” of the low-energy relativistic description, which depends on the interaction , but is expected to be regular across the quantum phase transition. We illustrate that the strongly coupled bosonic and fermionic excitations share a common velocity at the critical point.
- Received 15 August 2018
- Revised 3 May 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.137602
© 2019 American Physical Society