QSimFP QBH Seminar: Observation of Zitterbewegung in photonic microcavities

ABSTRACT The study of analogues to effects appearing in the domain of high energy physics is among the trends of modern condensed matter physics. By using analogue quantum systems in the lab, we can simulate effects that are otherwise out of reach using current technology. A prime example of such an effect is the ‘Zitterbewegung’ effect, something that has remained somewhat elusive since it was first predicted by Schrodinger for relativistic free electrons. These predictions concerned the counterintuitive trembling motion of propagating electrons perpendicular to the direction of travel and were later extended for all particles governed by the Dirac equation. It was recently proposed that by using optical microcavities this effect should be observable in the propagation path of highly photonic polaritons with a well-defined wavevector,1,2. These observations are possible due to the fact that Fabry–Perot optical microcavities allow direct imaging of the internal spinor wavefunction via photon tunnelling through the mirrors, along with supporting polarisation wave-vector coupling via TE-TM splitting (spin-orbit coupling analogue) 3 and in some cases birefringent coupling. Such systems have already allowed observation of a range of important physical effects such as optical spin-Hall effect4, the emergence of monopoles5 and the onset of the non-Abelian gauge fields6,7. This seminar aims to discuss the history of the Zitterbewegung effect, discuss its origins in a photonic microcavity system and present our findings in both non-periodic and periodic systems both of which contain direct observations of the effect.
References: 1. Sedov, E. S., Rubo, Y. G. & Kavokin, A. V. Zitterbewegung of exciton-polaritons. Phys. Rev. B 97, 245312 (2018).

2. Whittaker, C. E. et al. Optical analogue of Dresselhaus spin–orbit interaction in photonic graphene. Nat. Photonics 15, 193–196 (2021).

3. Shelykh, I. A. et al. Polariton polarization-sensitive phenomena in planar semiconductor microcavities. Semicond. Sci. Technol. 25, 013001 (2010).

4. Leyder, C. et al. Observation of the optical spin Hall effect. Nat. Phys. 3, 628–631 (2007).

5. Hivet, R. et al. Half-solitons in a polariton quantum fluid behave like magnetic monopoles. Nat. Phys. 8, 724–728 (2012).

6. Polimeno, L. et al. Experimental investigation of a non-Abelian gauge field in 2D perovskite photonic platform. Optica 8, 1442–1447 (2021).

7. Biegańska, D. et al. Collective excitations of exciton-polariton condensates in a synthetic gauge field. Phys. Rev. Lett. 127, 185301 (2021).

BIOSKETCH Seth Lovett is a postdoctoral research associate at the University of Sheffield currently working in the Low-dimensional structures and devices group (LDSD). He completed his PhD in 2023 (with minor corrections to his thesis ongoing) regarding the study of light-matter interactions in low dimensional structures with a focus on exciton-polaritons in inorganic semiconductor devices. His work so far has covered the demonstration of tuneable band gaps via a magnetic response for polaritons in 2D slab waveguides, the first direct observation of the Zitterbewegung effect for highly photonic polaritons in microcavity structures and more recently the observation of linear and non-linear compact localised states in micropillar lattice structures. He is also currently involved in projects centred around analogue gravity in polaritonic systems with a long-term goal of using said systems to study Penrose-like effects around an analogue polariton black-hole.