For distribution - thanks

[CM ICTP - Trieste]

									07/03

JOINT ICTP/SISSA CONDENSED MATTER SEMINARS
Academic Year 2006/07



Seminar Room - Main Building  (first floor)


Wednesday, 13 June -     4:00 p.m.


M.P. DAS   ( Australian National University, Canberra )


" What is new in the realm of quantum electronic transport in 
mesoscopic physics? "


Abstract

The prime signature of transport in quantum wires and quantum point 
contacts, namely the quantisation of conductance into 'Landauer steps' 
in units of 2e^2/h, appears to be adequately explained in terms of 
coherent transmission of electron waves through a loss free barrier.  
However, the picture of quantum coherent scattering at this 
phenomenological level can not address the central issue of metallic 
conduction: what causes dissipation in a ballistic quasi-one 
dimensional wire.
In this talk I shall present answer to this vexed question by many-body 
quantum kinetics, totally free of unwanted phenomenologies.  Our 
microscopic application of well-tested many-body methods leads not only 
to conductance quantisation by precise accounting for inelastic energy 
loss,  but we also resolve a long standing experimental enigma in the 
fluctuation spectra of a quantum point contact.  I shall also highlight 
some recent controversy regarding negative resistance in three- and 
four-terminal devices.
The talk will be presented at a pedagogic level.