Scalar, Vector and Tensor Interfaces between Light and Ultracold Spins

Dr Lincoln Turner

School of Physics, Monash University

3:30 pm Friday, 1 November 2013
EN313 Lecture Theatre (EN Building), Hawthorn.

Abstract
Condensed spins not only provide a new landscape of topological defects, excitations and interactions to explore but make possible new forms of measurement and control. In this talk I'll describe a quantum interface between condensed spins and light. Exploiting the vector and tensor parts of the electric dipole interaction enables optical measurement of the condensate magnetisation, and nematicity -- and optical control of linear and quadratic Zeeman effects.

A magnetic field gradient renders spin precession dependent on position. Measurement with the spin-light interface would realise magnetic resonance imaging (MRI) at the quantum limit. Resolution well below the optical diffraction limit appears achievable, enabling continuous imaging of topological defects dynamics in situ at the healing-length scale. While MRI promises read-out of the condensate wavefunction, I additionally present a protocol to write-in the wavefunction amplitude and phase, raising the prospect of 'wavefunction engineering' down to the finest length scales.

Spinor condensates possess a rich ground-state phase diagram, dependent on spin-changing interactions and on the quadratic Zeeman shift. I will conclude by describing the potential of Raman transitions to control optically the spinor ground-state, perhaps resulting in engineered spinor heterojunctions.

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