Analogue gravity enables the study of fields on curved spacetimes in the laboratory [1]: it is possible to create conditions in which waves in media propagate as though they were in the vicinity of a black hole [2] or on an expanding universe [3], for example.

In the Quantum Optics Group at Laboratoire Kastler Brossel, we study exciton- polaritons in semiconductor microcavities and make them behave as “fluids of light”. At present, we are interested in engineering the flow profile of the fluid of light to create the analogue of a rotating black hole — an effective spacetime characterised by two intangible surfaces: the event horizon (the point of no-return that bounds the interior of the black hole) and, further out, the ergosurface (a point beyond which waves and particles cannot remain at rest with respect to an outside observer).

This can be done by pumping the microcavity with a Laguerre-Gauss beam, thus inducing a vortex flow in the fluid of light [4]. We want to observe the propagation of small amplitude waves (e.g. density perturbations) as well as phase singularities (vortices and dark solitons) on this rotating spacetime. This could lead to the observation of effects such as the Hawking effect, rotational superradiance or the black hole bomb.

We have recently gathered promising preliminary experimental results with rotating spacetimes and are currently assembling a new experiment to push these investigations further.

We are looking for talented and motivated post-doc researchers. The selected candidate will work with the Polariton Team under the supervision of Prof Alberto Bramati.

Contact: Prof. Alberto Bramati, alberto.bramati@lkb.upmc.fr

[1] W. G. Unruh, Physical Review Letters 46, 1351 (1981).

[2] L.P. Euve, F. Michel, R. Parentani, T. Philbin, and G. Rousseaux, Physical Review Letters 117, 1079 (2016).

[3] S. Eckel, A. Kumar, T. Jacobson, I. B. Spielman, and G. K. Campbell, Physical Review X 8, 021021 (2018).

[4] M. J. Jacquet, T. Boulier, F. Claude, A. Maıtre, E. Cancellieri, C. Adrados, A. Amo, S. Pigeon, Q. Glorieux, A. Bramati, et al., Philosophical Transactions of the Royal Society A 378, 20190225 (2020), arXiv: 2002.00043.