SCIENCE AT THE EDGE SEMINAR

Friday, October 13 at 11:30am
Room 1400 Biomedical and Physical Sciences Bldg.
Refreshments at 11:15

Speaker: Carlo Piermarocchi
         Department of Physics and Astronomy
         University
        
Title:   Optical Quantum Control of Spin Interactions in Nanostructures

Abstract:

I will discuss theoretically the optical control of localized spins embedded
in a semiconductor host. Itinerant optical excitations, or excitons, in the
host material induce a Heisenberg coupling between the spins, which can be
controlled in a coherent and non-dissipative way by off-resonant laser
excitation.  I will discuss how this mechanism can be used to entangle spins
in bulk and quantum dot III-V systems, and how it can lead to light-induced
paramagnetic to ferromagnetic phase transitions in II-VI materials. One way
to extend the range of the spin coupling involves the use of Cavity Quantum
Electrodynamics, i.e. the physics of confined photons interacting with matter.
In this case, the key role in inducing a long range spin coupling is played by
peculiar states, called cavity polaritons, with a half-matter and half-light
character.