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BEGIN:VEVENT
DTSTAMP:20190923T133318Z
LAST-MODIFIED:20170911T151308Z
DTSTART:20170925T150000Z
DTEND:20170925T163000Z
UID:event1829@bu.edu
URL:http://physics.bu.edu/events/show/1829
SUMMARY:"Lieb-Schultz-Mattis Theorem and its generalizations from the Persp
ective of the Symmetry Protected Topological Phase"
DESCRIPTION:Featuring Cenke Xu \, University of California - Santa Barbara\
nHosted by: Anders Sandvik\n\nPart of the Condensed Matter Theory Seminar S
eries.\n\nWe ask whether a local Hamiltonian with a featureless (fully gapp
ed and\nnondegenerate) ground state could exist in certain quantum spin sys
tems. \nWe address this question by mapping the vicinity of certain quantum
critical point (or gapless phase) of the dâˆ’dimensional spin system under
study to the boundary of a (d+1)âˆ’dimensional bulk state\, and the lattic
e symmetry of the spin system acts as an on-site symmetry in the field theo
ry that describes both the selected critical point of the spin system\, and
the corresponding boundary state of the (d+1)âˆ’dimensional bulk. If the c
orresponding bulk state is a trivial state instead of a bosonic symmetry pr
otected topological (SPT) state\, then a featureless ground state of the sp
in system is allowed; if the corresponding bulk state is indeed a nontrivia
l SPT state\, then it likely excludes the existence of a featureless ground
state of the spin system. From this perspective we identify the spin syste
ms with SU(N) and SO(N) symmetries on one\, two and three dimensional latti
ces that permit a featureless ground state. We also verify our conclusions
by other methods\, including an explicit construction of these featureless
spin states.
LOCATION:SCI 328\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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