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DTSTAMP:20260912T130253Z
LAST-MODIFIED:20210219T160546Z
DTSTART:20210223T190000Z
DTEND:20210223T200000Z
UID:event2403@bu.edu
URL:http://physics.bu.edu/internal/events/show/2403
SUMMARY:Measuring Dynamic Heterogeneity in Supercooled Liquids
DESCRIPTION:Featuring Jack Stropko\, Boston University\, Physics Department
	\n\nPart of the Preliminary Oral Exam.\n\nGlasses are amorphous materials f
	ormed from supercooled liquids which behave mechanically like solids. The m
	echanism of the transition from supercooled liquid to glass is one of the o
	ldest unsolved problems in condensed matter physics. A natural question is 
	whether one theory can describe this transition among the huge range of gla
	ss-forming materials. Thus far no thermodynamic phase transitions have been
	 detected to explain the molecular slowdown in glass formers. However\, it 
	is now known that dynamic fluctuations in molecular diffusion\, called dyna
	mic heterogeneities\, arise as liquids are cooled toward the glass transiti
	on temperature. The length scale of dynamic heterogeneities grows with decr
	easing temperature\, but direct measurement has proven to be a challenge\, 
	as the dynamics must be resolved in space and time at very small scales. St
	able point defects in diamond called nitrogen vacancy (NV) centers can be u
	sed to study molecular dynamics to better understand how dynamic heterogene
	ities form. We have designed and built an NV detection setup with a special
	 low-temperature sample chamber to probe supercooled liquids near the glass
	 transition. I will discuss NV measurement schemes for estimating dynamic c
	orrelation lengths in supercooled liquids.
LOCATION: \, \, 
STATUS:CONFIRMED
CLASS:PUBLIC
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