There is a nice Q&A to this talk.
The Royal Institution of Great Britain (often the Royal Institution, abbreviated 'Ri' or 'RI') is an organisation for scientific education and research, based in the City of Westminster. It was founded in 1799 by the leading British scientists of the age, including Henry Cavendish and its first president, George Finch, the 9th Earl of Winchilsea. Its foundational principles were diffusing the knowledge of, and facilitating the general introduction of, useful mechanical inventions and improvements, as well as enhancing the application of science to the common purposes of life (including through teaching, courses of philosophical lectures, and experiments).
Much of the Institution's initial funding and the initial proposal for its founding were given by the Society for Bettering the Conditions and Improving the Comforts of the Poor, under the guidance of philanthropist Sir Thomas Bernard and American-born British scientist Sir Benjamin Thompson, Count Rumford. Since its founding it has been based at 21 Albemarle Street in Mayfair. Its Royal Charter was granted in 1800.
Definition from Wikipedia – Royal Institution
David Tong (physicist)
David Tong is a professor of theoretical physics at DAMTP in Cambridge, a fellow of Trinity College, Cambridge, and joint recipient of the 2008 Adams Prize. He was a postdoc at the MIT Center for Theoretical Physics. He was an Adjunct Professor at the Tata Institute of Fundamental Research (TIFR).
He is currently also a Simons Investigator. His main research interest is in Quantum Field Theory.His most-cited paper, "DBI in the sky", provides a possible observational test of one mechanism for inflation in the very early universe.
He is also well known amongst the students for his very enthusiastic lecturing and comprehensive lecture notes for courses he has taught at the University of Cambridge (most notably the ones on quantum field theory).
Definition from Wikipedia – David Tong (physicist)
Quantum field theory
In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity and quantum mechanics, but not general relativity's description of gravity. QFT is used in particle physics to construct physical models of subatomic particles and in condensed matter physics to construct models of quasiparticles.
QFT treats particles as excited states (also called quanta) of their underlying quantum fields, which are more fundamental than the particles. Interactions between particles are described by interaction terms in the Lagrangian involving their corresponding quantum fields. Each interaction can be visually represented by Feynman diagrams according to perturbation theory in quantum mechanics.
Definition from Wikipedia – Quantum field theory