What is moving in silica at 1 K? A computer study of the low-temperature anomalies

Abstract

Though the existence of two-level systems (TLS) is widely accepted to explain low temperature anomalies in many physical observables, knowledge about their properties is very rare. For silica which is one of the prototype glass-forming systems we elucidate the properties of the TLS via computer simulations by applying a systematic search algorithm. We get specific information in the configuration space, i.e. about relevant energy scales, the absolute number of TLS and electric dipole moments. Furthermore important insight about the real-space realization of the TLS can be obtained. Comparison with experimental observations is included.

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• Dynamics of liquid silica as explained by properties of the potential energy landscape
• The Origin of the Decoupling of Oxygen and Silicon Dynamics in Liquid Silica as Expressed by its Potential Energy Landscape
• Aging to Equilibrium Dynamics of SiO2
• Temperature-Dependent Defect Dynamics in the Network Glass SiO2
• Atomic delocalisation as a microscopic origin of two-level defects in Josephson junctions
• Relationship between two-level systems and quasi-localized normal modes in glasses
• Quantum Jamming: Critical Properties of a Quantum Mechanical Perceptron
• On the theory of resonant susceptibility of dielectric glasses in magnetic field
• A 3D investigation of delocalised oxygen two-level defects in Josephson junctions
• Universal Scaling in the Aging of the Strong Glass Former SiO${}_2$