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BEGIN:VEVENT
DTSTAMP:20260914T034548Z
LAST-MODIFIED:20171011T140140Z
DTSTART:20171025T150000Z
DTEND:20171025T163000Z
UID:event1823@bu.edu
URL:http://physics.bu.edu/internal/events/show/1823
SUMMARY:"Nearly deconfined spinon excitations in the square-lattice spin-1/
	2 Heisenberg antiferromagnet"
DESCRIPTION:Featuring Hui Shao\, Beijing Computational Science Research Cen
	ter\nHosted by: Anders Sandvik\n\nPart of the Condensed Matter Theory Semin
	ar Series.\n\nWe study the spin excitation spectrum of the spin-1/2 square-
	lattice\nHeisenberg antiferromagnet with QMC and an improved  stochastic\na
	nalytic continuation method. The spectra are in excellent agreement\nwith r
	ecent neutron scattering experiments on Cu(DCOO)2·4D2O\, where a\nbroad sp
	ectral-weight continuum at wavevector q = (\pi\,0) was\ninterpreted as deco
	nfined spinons. Our results show a similar\nreduction of the magnon weight 
	and a large continuum. Upon turning on\nthe Q interaction in the J-Q model\
	, we observe a rapid reduction of\nthe magnon weight to zero\, well before 
	the system undergoes a\ndeconfined quantum phase transition into a non-magn
	etic spontaneously\ndimerized state. Based on these results\, we re-interpr
	et the picture\nof deconfined spinons at (\pi\,0) in the experiments as nea
	rly\ndeconfined spinons—a precursor to deconfined quantum criticality. We
	\nalso introduce an effective model of the excitations (one magnon or\ntwo 
	spinons) which can reproduce the reduction of magnon weight and\nlowered ex
	citation energy at (\pi\,0) in the Heisenberg model\, as well\nas the rapid
	 loss of the (\pi\,0) magnon with increasing Q in the J-Q\nmodel.
LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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