Vincent Grison & Louis-Martin Poitras

Vincent Grison : Finite-temperature localization transition in a 1D disordered Bose gas : from Normal Fluid to Bose Glass, and more

The question of the effects of disorder on phases and phase transitions in quantum systems is a notoriously difficult problem in condensed matter - disordered bosons being a typical example.
Following previous works, we use bosonization, the replica method and the Functional Renormalization Group to determine the phase diagram of a one-dimensional disordered Bose gas at finite temperatures.
Our study suggests the existence of a thermal phase transition between a low-temperature many-body localized phase and a high-temperature normal fluid phase, in qualitative agreement with an earlier proposal.
We also uncover the existence of an intermediate glassy regime just above the transition temperature, controlling the behavior of the system on a significant range of length and time scales.

Louis-Martin Poitras : New generalized force-field for sulfide glasses and crystals

We present a generalized Born-Mayer force-field for modeling sulfide glasses and crystals relevant to all-solid-state batteries. The force-field captures key structural features, including sulfur-bridged tetrahedra and medium-range order, via a combination of two- and three-body terms. Fitted to crystal structures and experimental scattering data, the model reproduces the essential properties of the glassy and crystalline state. By accurately reproducing realistic structures across a range of sulfide compositions, the proposed force-field paves the way for investigating mechanical, dynamical and electrical properties of sulfide electrolytes through classical molecular dynamics simulations.