Condensed Matter Seminar: "Spin Fluctuations and Entanglement"

Wed, 01/28/2015 - 16:00 - 17:00
Ari Turner, Johns Hopkins University

I will compare the effects of quantum and thermal fluctuations in a
spin chain by calculating the probability distribution for spin
fluctuations in a segment.

The calculation will use the concept of an "entanglement Hamiltonian."
The entanglement Hamiltonian can be used to identify topological phases,
but I will show that it is helpful for long-wavelength correlations
as well as topological ones.

The entanglement Hamiltonian is an imaginary system that
describes the correlations of the ground state.  It cannot be measured
directly, but it is related to the  statistics of the  fluctuations,
so measuring the spin fluctuations of the atoms on the sites of an optical lattice
is an indirect way of measuring the entanglement Hamiltonian.