A New Look at Low--Temperature Anomalies in Glasses

TL;DR

This paper introduces a solvable spin-glass inspired model to explain low-temperature anomalies in glasses, providing insights into universality and predicting phases without tunneling excitations.

Contribution

It presents a new theoretical model that captures low-temperature glass anomalies and distinguishes between universal and non-universal properties.

Findings

Reproduces low-temperature anomalies of amorphous materials.

Provides a distribution of local potential parameters differing from standard models.

Predicts amorphous phases without low-energy tunneling excitations.

Abstract

We review a model--based rather than phenomenological approach to low--temperature anomalies in glasses. Specifically, we present a solvable model inspired by spin--glass theory that exhibits both, a glassy low--temperature phase, and a collection of double-- and single--well configurations in its potential energy landscape. The distribution of parameters characterizing the local potential energy configurations can be computed, and is found to differ from those assumed in the standard tunneling model and its variants. Still, low temperature anomalies characteristic of amorphous materials are reproduced. More importantly perhaps, we obtain a clue to the universality issue. That is, we are able to distinguish between properties which can be expected to be universal and those which cannot. Our theory also predicts the existence, under suitable circumstances of amorphous phases without low--energy tunneling excitations.