Evidence for a Generalized Tunneling Model - Investigating the Effect of Thermal Cycling on the Spectrum of Two-Level Systems in Amorphous Solids

by Mr. Yigal Reiss

Physics department, BGU

at Condensed Matter Seminar

Mon, 13 Jan 2025, 11:40
Sacta-Rashi Building for Physics (54), room 207

Abstract

Structural two level systems (TLSs) ubiquitous in amorphous solids are dramatically sensitive to thermal cycling to about 20K and then back to low temperature, a process upon which the excitation energy of most TLSs is significantly changed. Using Monte Carlo simulations we demonstrate that this phenomenon is not contained within the standard tunneling model, but is well explained by a model that includes an additional set of TLSs that are pseudo-gapped at low energies, yet possess strong strain interaction through which they generate significant dynamical disorder upon thermal cycling. Our results give support for the general applicability of the Two-TLS model to amorphous solids at low temperatures, in that nearing our understanding of the low-temperature universality of phonon attenuation in amorphous solids and of long-time fluctuations of relaxation times in quantum circuits.

Created on 12-01-2025 by Naamneh, Muntaser (mnaamneh)
Updaded on 12-01-2025 by Naamneh, Muntaser (mnaamneh)