Open Access. Powered by Scholars. Published by Universities.®
- Publication Type
Articles 1 - 2 of 2
Full-Text Articles in Quantum Physics
Quantum Phase Transitions In Disordered Boson Systems, Zhiyuan Yao
Quantum Phase Transitions In Disordered Boson Systems, Zhiyuan Yao
Doctoral Dissertations
In this dissertation, we study the superfluid-insulator quantum phase transition in disordered boson systems. Recently, there has been considerable controversy over the validity of the scaling relations of the superfluid--Bose-glass quantum phase transition in three dimensions. Results from experimental and numerical studies on disordered quantum magnets contradict the scaling relations and the associated conventional scaling hypothesis for the singular part of the free energy. We determine various critical exponents of the superfluid--Bose-glass quantum phase transition in three-dimensional disordered Bose-Hubbard model through extensive Monte Carlo simulations. Our numerical study shows the previous studies on disordered quantum magnets were performed outside the …
Quadrupolar Quantum Criticality On A Fractal, Jonathan D'Emidio, Simon Lovell, Ribhu K. Kaul
Quadrupolar Quantum Criticality On A Fractal, Jonathan D'Emidio, Simon Lovell, Ribhu K. Kaul
Physics and Astronomy Faculty Publications
We study the ground state ordering of quadrupolar ordered S = 1 magnets as a function of spin dilution probability p on the triangular lattice. In sharp contrast to the ordering of S = 1/2 dipolar Néel magnets on percolating clusters, we find that the quadrupolar magnets are quantum disordered at the percolation threshold, p = p∗. Further we find that long-range quadrupolar order is present for all p < p∗ and vanishes first exactly at p∗. Strong evidence for scaling behavior close to p∗ points to an unusual quantum criticality without fine tuning that …