<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>All,</div><div><br></div><div>Prof Charles Adams, from Durham University, will be visiting the department tomorrow and has agreed to give a talk on recent work from his group. Title and abstract are below.</div><div><br></div><div><br></div><div><b>Title:</b> Strongly interacting photons!<br><b>Time:</b> 3pm, 20th February</div><div><b>Location:</b> SUPA room<br><b>Abstract: </b>In optics, we are familiar with the idea that photons do not interact, even in a non-linear medium the interaction is very weak. However, recently experiments have shown that by coupling optical photons to highly-excited Rydberg states [1] it is possible to realise giant optical non-linearities [2] and hence strong photon-photon interactions [3]. The photon-photon interaction is mediated by the large<br>dipole-dipole interactions between highly-excited Rydberg atoms. The interesting challenges ahead are whether it is possible to tailor these interactions to realise high-fidelity photonic quantum gates and hence implement all-optical quantum computing [4], or to realise strong photon-photons interactions without Rydberg excitations by reducing the length scales [5]?<br><br>[1] A. Mohapatra et al. Phys. Rev. Lett. 98, 113003 (2007).<br>[2] J. Pritchard et al. Phys. Rev. Lett. 105, 193603 (2010).<br>[3] D. Maxwell et al. Phys. Rev. Lett. 110, 103001 (2013).<br>[4] D. Paredes-Barato and C. S. Adams, Phys. Rev. Lett. 112, 040501 (2014).<br>[5] J. Keaveney et al. Phys. Rev. Lett. 108, 173601 (2012).</div><div><br></div><div><br></div><div><br></div><div><div>regards,</div><div>Griff</div></div></body></html>