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SUMMARY:Low-energy excitation in glassy solids
DTSTART:20170515T140000
DTEND:20170515T153000
DTSTAMP:20260506T132941Z
UID:b878de3bd94f8d030dde6146fc0dc1ccfa2537be3ac62e5ddb0badb4
CATEGORIES:Conferences - Seminars
DESCRIPTION:Edan Lerner\nThe disordered microstructure of glassy solids gi
 ves rise to a population of soft excitations whose density determine vario
 us mechanical\, dynamic and thermodynamic properties of the glass. Despite
  their fundamental importance\, much is unknown about the abundance of the
 se `glassy modes'\, their spatial structure and degree of universality. In
  this seminar I will present results from numerical simulations of several
  model glasses showing that the low-frequency tail of the density of state
 s follows a universal law D(ω)∼ω^4 up to the vicinity of the largest 
 wavelength shear-wave frequency. I will discuss the localization propertie
 s of soft glassy modes\, and the effects of preparation protocol\, interna
 l stresses\, and dimensionality on their statistics. Finally\, I will move
  away from the harmonic regime and introduce an alternative definition of 
 low-energy excitations in glasses that properly accounts for anharmoniciti
 es of the potential energy. I will show that these nonlinear excitations\,
  unlike soft quasi-localized harmonic modes\, do not hybridize with extend
 ed excitations. Nonlinear excitations therefore coexist with plane-waves i
 n phononic frequency bands\, making them good candidates as the fundamenta
 l low-energy excitations in glassy solids
LOCATION:BSP 407
STATUS:CONFIRMED
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