BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Collective electronic transport close to the metal-insulator or su
 perconductor insulator transitions. - Mueller\, M (Universit de Genve)
DTSTART:20081217T100000Z
DTEND:20081217T110000Z
UID:TALK15740@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Insulators close to the transition to a metal or a superconduc
 tor exhibit interesting collective electronic phenomena which are prominen
 tly reflected in transport properties. An important feature in systems clo
 se to the metal-insulator transition is the apparently purely electronic n
 ature of activated transport seen in experiments. This does not fit into t
 he standard theory of phonon-assisted hopping conduction and has remained 
 an unexplained puzzle for decades. It also seems to contradict recent theo
 ries of many body localization (localization in the Fock space of interact
 ing systems)\, which have predicted a finite temperature metal insulator t
 ransition for interacting\, Anderson localized electrons. I will address t
 his problem for Anderson insulators with a single-particle localization le
 ngth much larger than the mean distance between electrons. I will argue th
 at under these circumstances Coulomb interactions drive the electrons into
  a strongly correlated quantum glass phase with a gapless spectrum of delo
 calized collective excitations which act as a bath with which individual e
 lectrons can exchange energy. However\, the same reasoning does not necess
 arily apply close to a insulator-to-superconductor transition\, where elec
 trons are bound into preformed Cooper pairs and Coulomb interactions are w
 eak. I will argue that these systems are promising candidates to exhibit s
 trong remnants of many body localization\, which may be the key to an expl
 anation for their unusual transport properties.
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR