New preprint about quantum criticality of diluted quantum matter
New preprint about quantum criticality of diluted quantum matter
13. Mai 2025
New preprint entitled „Quantum Monte Carlo study of the bond- and site-diluted transverse-field Ising model“ (arXiv:2505.07627) dealing with the effects of dilution on the critical properties of quantum matter! This work is a nice piece of work from Calvin Krämer and Max Hörmann from kps_lab at FAU Erlangen-Nürnberg.
We study the transverse-field Ising model on a square lattice with bond- and site-dilution at zero temperature by stochastic series expansion quantum Monte Carlo simulations. Tuning the transverse field h and the dilution p, the quantum phase diagram of both models is explored. Both quantum phase diagrams show long-range order for small h and small p. The ordered phase of each is separated from the disordered (quantum) Griffiths phase by second-order phase transitions on two critical lines touching at a multi-critical point. Using Binder ratios we locate quantum critical points with high accuracy. The order-parameter critical exponent β and the average correlation-length exponent νav are determined along the critical lines and at the multi-critical points for the first time via finite-size scaling. We find three internally consistent sets of critical exponents and compare them with potentially connected universality classes. The quantum Griffiths phase in the vicinity of the phase transition lines is analyzed through the local susceptibility. Our results indicate that activated scaling occurs not only at the percolation transition, but also at the phase transition line for p smaller than the percolation threshold pc.
We study the transverse-field Ising model on a square lattice with bond- and site-dilution at zero temperature by stochastic series expansion quantum Monte Carlo simulations. Tuning the transverse field h and the dilution p, the quantum phase diagram of both models is explored. Both quantum phase diagrams show long-range order for small h and small p. The ordered phase of each is separated from the disordered (quantum) Griffiths phase by second-order phase transitions on two critical lines touching at a multi-critical point. Using Binder ratios we locate quantum critical points with high accuracy. The order-parameter critical exponent β and the average correlation-length exponent νav are determined along the critical lines and at the multi-critical points for the first time via finite-size scaling. We find three internally consistent sets of critical exponents and compare them with potentially connected universality classes. The quantum Griffiths phase in the vicinity of the phase transition lines is analyzed through the local susceptibility. Our results indicate that activated scaling occurs not only at the percolation transition, but also at the phase transition line for p smaller than the percolation threshold pc.