Abstract：

Low-temperature crystals can be modeled as harmonic vibrations, the phonons, around a perfect lattice. The resulting Debye theory perfectly predicts thermodynamic and transport properties. Low-temperature glasses instead display all kind of anomalies with respect to this description: anomalous specific heat and thermal conductivity; activated slow dynamics across barriers inside the glass; an abundance of soft vibration modes with respect to the Debye law, the so-called Boson Peak; marginal stability of mechanical excitations; a plastic and irreversible response to arbitrarily small strain amplitudes. Here, we show that all these observations can be rationalized as the remanent of a novel phase transition—the Gardner transition—predicted by the mean field theory of glasses. The Gardner transition distinguishes between two types of amorphous solids: the simple mechanically stable glass and the marginally-stable glass. We explore numerical methods to detect the Gardner transition in several model glass formers. We show that the transition is associated to a significant growth of time and length scales, and a spatially heterogeneous organization of cages that confine particles' vibrations. We further provide concrete proposals for experiments in low-temperature glasses.
 
报告人介绍：
2002-2006          B.S.  Department of Physics, Fudan University, Shanghai, China
2006-2012          PhD  Levich Institute and Physics Department, The City College of New York, New York, NY, USA
2012/9-2012/11    Postdoctoral   Ecole Normale Superieure, Paris, France
2012/9-2013/10    Postdoctoral   Duke University, Durham, NC, USA
2013/11-2014/10   Postdoctoral   Sapienza Universita di Roma, Roma, Italy
2014/11-2015/11   Postdoctoral   Ecole Normale Superieure, Paris, France