Configurational Entropy of Quantum Liquids Based on the Potential Energy Landscape Formalism

The potential energy landscape (PEL) formalism is a framework within statistical mechanics that allows one to describe the behavior of classical low-temperature liquids and glasses. Recently, the PEL formalism has been extended to the case of quantum liquids and glasses. In this talk, I will present results from path-integral molecular dynamics simulations of a glass former model liquid (Lennard-Jones binary mixture) and show that classical and quantum liquids can be described in a similar manner when using the PEL formalism. I will show that, as for the classical case, one can define a configurational entropy for a quantum liquid, S_conf(T). Importantly, the so obtained S_conf(T) is related with the diffusion coefficient of the liquid as predicted by the Adam-Gibbs relation (which has been tested extensively for classical liquids). This implies that the dynamics of the quantum liquid is related to the topography of the associated PEL.