Smeared quantum phase transition in the dissipative random quantum Ising model

TL;DR

This paper studies how Ohmic dissipation affects the quantum phase transition in a disordered transverse-field Ising model, showing that dissipation smears the critical point and Griffiths phase, confirming recent theoretical predictions.

Contribution

It provides numerical evidence that Ohmic dissipation destroys the quantum critical point in the disordered Ising model, supporting the smeared transition theory.

Findings

Ohmic dissipation destroys the quantum critical point

Quantum Griffiths phase is smeared by dissipation

Results confirm recent theoretical predictions

Abstract

We investigate the quantum phase transition in the random transverse-field Ising model under the influence of Ohmic dissipation. To this end, we numerically implement a strong-disorder renormalization-group scheme. We find that Ohmic dissipation destroys the quantum critical point and the associated quantum Griffiths phase by smearing. Our results quantitatively confirm a recent theory [Phys. Rev. Lett. {\bf 100}, 240601 (2008)] of smeared quantum phase transitions.