IoP Lunch Seminar (series)
Come and enjoy a slice of pizza whilst learning about what your fellow colleagues are up to! This month's speakers are Bart van Dam (Hard Condensed Matter), Chun Chia Chen (Quantum Gases and Quantum Information) and Jean-Sébastien Caux (Condensed Matter Theory).
Bart van Dam (PhD Student - Hard Condensed Matter Theory) - Emission efficiency of silicon quantum dots in the visible range
Silicon quantum dots (Si QDs) are a promising alternative to toxic and rare material QDs for application in lighting technologies. For competitive emission properties, however, the emission rate needs to be considerably improved. This is the case in Si QDs capped with organic ligands (C-SiQDs). Nevertheless, despite high radiative rates approaching those of direct bandgap QDs the emission efficiency in the visible range remains comparatively low. In this talk I will discuss the microscopic processes, such as photoluminescence ‘blinking’, that underlie and limit the ensemble emission efficiency of C-Si QDs.
Chun Chia Chen (PhD Student - Quantum Gases and Quantum Information) - Towards a Perpetual Bose-Einstein Condensate
Production of Bose-Einstein condensates (BECs) has always been a two stage process, first laser cooling a gas sample, then cooling evaporatively until degeneracy is reached. As a result, BECs and devices based on BEC such as atom lasers are pulsed. Applications like atom interferometers would benefit greatly from a perpetual source of condensate. We are developing such a perpetual source in which we separate the cooling stages in space rather than time and protect the condensate from scattered photons using distance, baffles and a “transparency” beam. We have now demonstrated a perpetual MOT of >109 88Sr atoms on a 7.4-kHz wide laser cooling transition with a continuous loading rate >108 atoms/s. Critically, we have also validated the effectiveness of our architecture in protecting a BEC from scattered broad-linewidth laser cooling light, which is used in the first cooling stages. These are crucial steps towards demonstrating a perpetual BEC and atom laser.
Jean-Sébastien Caux (Staff Member - Condensed Matter Theory) - Dynamics and relaxation in integrable quantum systems
Recent years have witnessed rapid progress in the use of integrability in characterizing the out-of-equilibrium dynamics of low-dimensional systems such as interacting atomic gases and quantum spin chains. This talk will provide an introduction to these developments, with a particular focus on the Quench Action method and on interesting open issues and challenges.
As a postscript, he will also present some details on SciPost, the new publication portal by and for scientists.