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BEGIN:VEVENT
DTSTAMP:20260831T110146Z
LAST-MODIFIED:20160829T185559Z
DTSTART:20160909T143000Z
DTEND:20160909T153000Z
UID:event1628@bu.edu
URL:http://physics.bu.edu/internal/events/show/1628
SUMMARY:Unexpected effects in periodic driving of gapless topological syste
	ms
DESCRIPTION:Featuring Mike Kolodrubetz\, UC Berkeley\n\nPart of the Condens
	ed Matter Theory Seminar Series.\n\nFloquet engineering is the emerging fie
	ld of using periodic drive to realize novel Hamiltonians that are difficult
	 or impossible to realize in static systems. In this talk I will highlight 
	two examples where such a drive yields unexpected effects. First\, I will d
	iscuss Floquet engineering of Weyl semimetals\, which has been proposed for
	 ultracold atoms in optical lattices. Unlike their condensed matter counter
	parts\, these systems naturally have large magnetic fields whose two-dimens
	ional physics is described by the Hofstadter butterfly. I will show how one
	 realizes it natural extension\, the "Weyl butterfly\," in a three-dimensio
	nal Weyl semimetal and discuss how the chiral anomaly generalizes beyond th
	e weak-field limit. In particular\, I will describe how the chiral anomaly 
	inherits the fractal structure of the Weyl butterfly\, exhibiting a fractal
	 set of quantized anomalies that originate from the gaps of the butterfly. 
	Second\, I will switch gears to a condensed matter realization of Floquet e
	ngineering\, namely periodic driving of surface states in topological insul
	ators. While in the absence of driving surface states are well-defined gapp
	ed excitations\, I will show that driving the surface of such system natura
	lly leads to resonant surface-bulk coupling. Furthermore\, this coupling le
	ads to coherent bulk-surface oscillations in the Wigner distribution -- a n
	on-equilbrium observable measurable via ARPES -- and may be responsible for
	 the non-adiabatic signal seen in recent experiments.
LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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