Friday, 24th February 2017 at 15:30

Physics Colloquia Series – Astor Lecture

Plasma physics helps in establishing an upper bound for the photon mass
Dr. Dmitri D. Ryutov
Lawrence Livermore National Laboratory
Tuesday, 7 March 2017 at 14.00

‘The applied side of Bell nonlocality’
Friday, 17 February 2017 at 15:30

Professor Val Gibson, Cambridge, will present this Friday’s Physics Colloquium entitled ‘The Beauty of Flavour - Latest results from the LHCb experiment at the Large Hadron Collider’ at the usual time of 3.30pm in the Martin Wood Lecture Theatre (3 February 2017). Tea & Coffee will follow in the Clarendon Labs Common Room.

The behaviour of the early universe just after the Big Bang is one of the most intriguing basic questions in all of science, and is extraordinarily difficult to answer because of insurmountable issues associated with replaying the Big Bang in the laboratory. One route towards the answer -- which lies at the intersection between cosmology and materials physics -- is to use laboratory materials to test the so-called "Kibble-Zurek" scaling laws proposed for the formation of defects such as cosmic strings in the early universe.

The early 1960s witnessed a wealth of elementary particles described in terms of simple combinations of a few more elementary units, dubbed quarks. The known mesons and baryons could all be described as states of quark-antiquark or three quarks. However, it was not understood why certain more elaborate combinations, such as (two quarks + two antiquarks) or (four quarks + one antiquark) had not been observed. It has taken nearly half a century, but these "exotic" particles are now beginning to be seen and understood.

The gamma-ray band of the electromagnetic spectrum probes some of the most extreme environments in the Universe. Photons of these very-high energies can only be produced by the interactions of subatomic particles that have been accelerated to almost the speed of light. This acceleration occurs in a surprisingly wide variety of astrophysical sources: close to black holes and neutron stars, in the blast waves of supernova explosions, and in the relativistic jets of active galaxies.

From the earliest commercial production of electronic image sensors for television in the 1950s, to the diverse application of specialist silicon image sensors for the Hubble space Telescope to digital dentistry this talk will outline the manufacturing technology and changes through 60 years at e2v. Somewhat surprisingly, there are today lessons to be learned, and technologies to be applied from this to the emerging new platform technology of ultra-cold atom sensing and metrology.

Janus particles are micro- or nano-scale particles whose surfaces have two or more distinct physical properties. Such asymmetry results in interesting self-assembly properties, but homogeneous Janus particles can be difficult to synthesize. The protein BslA (Bacterial Surface Layer A) is a small (~4 nm) protein produced by the bacterium Bacillus subtilis that has a hydrophilic ‘body’ to which is appended a surface-exposed hydrophobic ‘cap’.

Everything around us, everything each of us has ever experienced, and virtually everything underpinning our technological society and economy is governed by quantum mechanics. Yet this most fundamental physical theory of nature often feels as if it is a set of somewhat eerie and counterintuitive ideas of no direct relevance to our lives. Why is this?