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Condensed Matter Seminars

ics Condensed Matter
Thursday, October 15, 2015
11:00 AM
Physics Building, Room 313
Dima Bolmatov [Host: Genya Kolomeisky]
Brookhaven National Lab
"Phononics in liquids and supercritical fluids"

Abstract: While physicists have a good theoretical understanding of the heat capacity of both solids and gases, a general theory of the heat capacity of liquids has always remained elusive. Apart from being an awkward hole in our knowledge of condensed-matter physics, heat capacity – the amount of heat needed to change a substance's temperature by a certain amount – is a technologically relevant quantity that it would be nice to be able to predict1. I will introduce a phonon-based approach to liquids2 and supercritical fluids3, and describe its thermodynamics in terms of phonon excitations. I will show that the effective Hamiltonian4 has a transverse phononic gaps and explain their evolution with temperature variations. I will explain how the introduced formalism covers the Debye theory of solids, the phonon theory of liquids, and thermodynamic limits such as the Delong-Petit and the ideal gas thermodynamic limits. The experimental evidence for the new thermodynamic boundary (the Frenkel line) on the pressure-temperature phase diagram will be demonstrated5. Finally, I will discuss the phonon propagation and localization effects in liquids above and below the Frenkel line, and outline new directions towards phonon band gaps engineering and sound manipulation.

To add a speaker, send an email to phys-speakers@Virginia.EDU. Please include the seminar type (e.g. Condensed Matter Seminars), date, name of the speaker, title of talk, and an abstract (if available).