[QIP-Sem] MIT Quantum Information Processing Seminar Announcement

[QIP-Sem Mailing List]

Next week's MIT QIP seminar will take place on Monday, Oct. 25 at 
16:00 in 4-237, and features:


Bipartite Entanglement and Entropic Boundary Law in Lattice Spin Systems

by Paola Zanardi (Institute for Scientific Interchange Foundation, 
Torino, Italy)

ABSTRACT

We investigate bipartite entanglement in spin-1/2 systems on a 
generic lattice. For states that are an equal superposition of 
elements of a group G of spin flips acting on the fully polarized 
state $\ket{0}^{\otimes n}$, we find that the von Neumann entropy 
depends only on the boundary between the two subsystems A and B. 
These states are stabilized by the group G. A physical realization of 
such states is given by the ground state manifold of the Kitaev's 
model on a Riemann surface of genus g. For a square lattice, we find 
that the entropy of entanglement is bounded from above and below by 
functions linear in the perimeter of the subsystem A and is equal to 
the perimeter (up to an additive constant) when A is convex. The 
entropy of entanglement is shown to be related to the topological 
order of this model. Finally, we find that some of the ground states 
are absolutely entangled, i.e., no partition has zero entanglement. 
We also provide several examples for the square lattice.

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