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ICMT Seminar: "SU(2)-invariant topological quantum spin liquids"

Event Type
Institute for Condensed Matter Physics
190 ESB
Oct 16, 2017   12:00 pm  
Alexander Seidel, Washington University in St. Louis
Originating Calendar
Physics - Institute for Condensed Matter Theory Seminar

Anderson's idea of a (short-ranged) resonating valence bond (RVB) spin liquid has been the first ever proposal of what we now understand as a “topologically ordered” state of matter. Since then, a wealth of exactly solvable lattice models has been constructed that have topologically ordered ground states. For a long time, however, it has been challenging to construct solvable parent Hamiltonians for Anderson's original vision, according to which the ground state has an unbroken SU(2) spin rotational symmetry and is dominated by fluctuations of singlet valence bonds. The kagome lattice is the simplest lattice geometry for which a parent Hamiltonian stabilizing a prototypical spin-1/2 short-ranged RVB wave function has been constructed and definitive evidence has been given for the topological nature of this state. This talk will review the construction of RVB parent Hamiltonians for the kagome lattice, discuss their ground state uniqueness modulo topological degeneracies, and present numerical evaluation of correlation functions and entanglement properties. The latter requires avoiding the sign problem of the traditional Sutherland “loop-gas” representation.

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