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SUMMARY:Cosmology in Charge Density Wave systems 
DTSTART:20110407T111500
DTSTAMP:20260406T170522Z
UID:b3aa5c199eb19f4fcceb4c62f1111cdb2ef9bf7f3ab72028ca6201ae
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. D. Mihailovic\, Department of Complex Matter Institut \n
 The study of the temporal evolution of systems undergoing symmetry breakin
 g phase transitions¬ whether it is in condensed-matter physics\, cosmolog
 y or [1]finance ¬is dif[1]ficult because they are hard to repeat\, or the
 y occur very rapidly. We report a high-time-resolution study of the evolut
 ion of both bosonic and fermionic excitations through an electronic symmet
 ry breaking phase transition. The model system of choice are charge-densit
 y-wave materials where phase fluctuations are much slower than amplitude r
 elaxation\, which makes modeling significantly easier. Periodically quench
 ing our system with femtosecond optical pulses\, we detect hitherto-unreco
 rded coherent aperiodic undulations of the order parameter\, critical slow
 ing down of the collective mode and evolution of the particle–hole gap a
 s the system evolves through the transition. Modelling on the basis of Gin
 zburg–-Landau theory is used to reproduce the observations without free 
 parameters. Of particular interest is the observation of spectrotemporal d
 istortions arising from spontaneous annihilation of topological defects\, 
 analogous to those discussed by the Kibble--Zurek cosmological model.
LOCATION:PH L1 503
STATUS:CONFIRMED
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