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DTSTAMP:20261020T034717Z
LAST-MODIFIED:20170418T131720Z
DTSTART:20170426T150000Z
DTEND:20170426T160000Z
UID:event1745@bu.edu
URL:http://physics.bu.edu/internal/events/show/1745
SUMMARY:Competition between Bose glass and superfluid phases in quantum ant
	iferromagnets
DESCRIPTION:Featuring Sylvain Capponi\, Toulouse university & BU\nHosted by
	: Anders Sandvik\n\nPart of the Condensed Matter Theory Seminar Series.\n\n
	Building on recent NMR experiments [1]\, we theoretically investigate the h
	igh magnetic field regime of the disordered quasi-one-dimensional S=1 antif
	erromagnetic material DTNX. The interplay between disorder\, chemically con
	trolled by Br-doping\, interactions\, and the external magnetic field\, lea
	ds to a very rich phase diagram. Beyond the well-known antiferromagneticall
	y ordered regime\, analog of a Bose condensate of magnons\, we unveil a res
	urgence of phase coherence at higher field\, induced by the doping [2]. Suc
	h a ``mini-condensation'' contrasts with previously reported Bose-glass phy
	sics in the same regime and should be accessible to future experiments.\n\n
	In a second part\, I will discuss recent findings regarding the one-dimensi
	onal superfluid-Bose glass transition at T=0 in S=1/2 XXZ chain [3]. As a f
	unction of interaction and disorder strength\, we identify a Berezinskii-Ko
	sterlitz-Thouless critical line with two different regimes. At small attrac
	tion where critical disorder is weak compared to the bandwidth\, the critic
	al Luttinger parameter K takes its universal Giamarchi-Schulz value 3/2. Co
	nversely\, a non-universal K>3/2 emerges for stronger attraction where weak
	-link physics is relevant. In this strong disorder regime\, the transition 
	is characterized by self-similar power-law distributed weak links with a co
	ntinuously varying characteristic exponent.\n\nRefs:\n[1] A. Orlova et al.\
	, Phys. Rev. Lett. 118\, 067203 (2017)\n[2] M. Dupont\, S. Capponi\, N. Laf
	lorencie\, Phys. Rev. Lett. 118\, 067204 (2017)\n[3] E. Doggen\, G. LemariĆ
	©\, S. Capponi\, N. Laflorencie\, arXiv:1704.02257
LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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