Departmental Seminar

Toplogical Polaritons and Chiral Bogoliubons

Associate Professor Timothy Liew
Division of Physics and Applied Physics, Nanyang Technological University, Singapore
Friday 27 May 2016 2–3pm
Le Couteur Seminar Room (L3.17)

In electronic and photonic systems it is now well-established that non-trivial band-structures result in chiral edge states that are fully robust against scattering with disorder. In a recent work we introduced a theoretical scheme for topological polaritons in semiconductor microcavities and topological indirect-excitons in coupled quantum wells. The scheme is based on the spin-orbit coupling of exciton-polaritons or excitons in hexagonal lattice potentials and requires a magnetic field to break time-inversion symmetry. More recently, we have also considered the availability of nonlinearity in polariton systems and how it can lead to an interaction-induced mechanism of topological states. In a lattice of vortex-antivortex pairs we obtain a topological Bogoliubov spectrum, where fluctuations can propagate on top of a polariton condensate in topologically protected chiral edge modes. Remarkably, this mechanism of introducing topological behaviour no longer requires a magnetic field to break time reversal symmetry. Time reversal symmetry is rather broken locally by the choice of sign of phase winding in unit cells of the vortex-antivortex lattice.

The seminar is part of the mini-workshop on polaritonics hosted by the Polariton BEC Group.

Full program is found here:

https://polaritonbec.org/2016/05/23/mini-workshop-program/

Contact

Prof Timothy Liew
tchliew@gmail.com
(02)61257849

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