Virtual Quantum Cafe: David Reichman

Quantum Café is CCQ’s ongoing seminar series: open to all bona fide members of the greater NYC scientific community and held every second week, Quantum Café presents a series of informal, highly interactive talks, typically by external speakers, which present the most interesting recent developments and open questions in our field.

Title: Tunneling Effects in Low-Temperature Amorphous Materials

Abstract: The thermodynamics of perfect crystals in the low temperature (quantum) regime has been fully understood since Debye’s seminal 1912 calculation of
the specific heat. In 1971 it was discovered experimentally that the thermodynamic properties of amorphous materials such as glasses differ dramatically at low temperatures from those of perfect crystals. A phenomenological theory to explain the striking behavior exhibited by such disordered solids at low temperatures was put forward independently by Anderson, Halperin and Varma, and by Phillips. This theory, based on the role of quantum tunneling, has withstood many experimental tests over the last five decades. Despite this success, a direct microscopic confirmation of the theory, and a physical understanding of precisely what is tunneling, is lacking. In this talk I will discuss the first realistic, detailed computer simulation tests of this picture which enable us to probe these and other outstanding questions related to the quantum nature of amorphous solids in the low temperature regime.