Fred Combley Colloquia

Fred CombleyThe Fred Combley Lectures are a series of annual lectures given by distinguished researchers in the fields of physics and astrophysics. These lectures are of general interest to the major areas of research in the department.

The series is named after Fred Combley, a former Head of Department (1990-1995) and Dean of the Faculty of Science (1995-1998). Fred was an experimental particle physicist who worked with leptons and photons, contributing in the mid 70s to the first high-precision measurement of the anomalous magnetic moment of the muon. His work confirmed that positive and negative muons had the same anomalous magnetic moment, set a much improved upper limit on the muon electric dipole moment and tested the time dilation formula of special relativity.

Despite the heavy administrative load he shouldered as Head of Department and then Dean of Faculty, he continued to be a conscientious and supportive supervisor of research students and an effective group leader. Fred was an inspirational and innovative teacher. He pioneered the use of personal computers in university teaching and learning, and later was the first member of the department to develop an entirely student-led lecture course. He was immensely popular with the students and much in demand as a project supervisor.

An excellent speaker himself, Fred was passionate about communication and an enthusiastic supporter of departmental seminars and colloquia. The bell donated to the Department in his memory recalls his habit of rousting colleagues and students out of their offices to come and listen to a seminar, even if its subject matter was not immediately relevant to their research interests.

The information for the invited talks is below, with the respective contact person in each case.


Schedule for 2018 Colloquia

Area of research Name Date, time and location

Inorganic semiconductors

Professor Jonathan Finley, Technical University Munich

Semiconductor Artificial Atoms for Photonic Quantum Technologies

Abstract:
Many groups worldwide currently explore discrete quantum systems, partly of course due to fundamental interest, but also to assess their potential for use as hardware for quantum science and technology (QST). Prominent examples include single atoms trapped in optical cavities, quantised currents and fluxes in superconducting circuits, the spin of single charges trapped in semiconductors and individual quanta of light propagating in photonic systems.

At the core of QST are the notions of superposition; the ability to prepare a system in a coherent mixture of its eigenstates and entanglement; the ability to bring multi-partite quantum systems into non-separable superpositions, such that the quantum state of one particle is intimately related to that of the others. It turns out that superposition and entanglement lie at the heart of quantum (Q) technologies such as Q-communication, Q-metrology, Q-sensing and Q-computation. However, in most multi-partite quantum systems superposition and entanglement are fragile, typically being destroyed before something has been sensed, before information has been transferred or before an algorithm has been completed. As such, much of the current research into QST, focuses on understanding the mechanisms by which quantum coherence and entanglement disappear in few body quantum systems.

In this lecture we will focus on semiconductor quantum dots (QDs) as one of the many systems currently being explored. In many respects QDs are akin to artificial atoms: they have manifestly atom-like properties including Fourier limited, narrowband (∼GHz) optical transitions at low temperatures, nearly fully coherent light-matter interactions and charge and spin excitations which are largely decoupled from their solid-state environment. We will take a pedagogical look at the use of quantum dots for QST, including storing photonic quantum states in superpositions of the spin-states of single charges, deterministically generating non-classical states of light such as single photons and photon pairs and detecting non-classical states of light. Moreover, we will explore some of their mid and long-term prospects.

Contact: Professor Mark Fox 
(mark.fox@sheffield.ac.uk) 

14:00, Wednesday 14th March 2018
LT 7, Hicks Building

Astrophysics

Professor Don Pollacco, University of Warwick

Earth Analogs: Methods and limitations in the detection and characterisation of terrestrial exoplanets and their atmospheres

Abstract:
One of the greatest discoveries in astronomy over the last 10 years has been the discovery of earth like planets. In this talk I’ll review what we currently know about this population and what we would like to know including the finger prints of life. To achieve this I’ll discuss some of the issues that will need to be overcome over the next decade.

Professor Don Pollacco is one of the leading scientists in the field of extrasolar planets. He was responsible for the most successful ground based planet detection experiment SuperWASP (Wide Angle Search for Planets). Don Pollacco is a senior member in the UK Exoplanets community and science coordinator for the future ESA science mission PLATO (PLAnetary Transits and Oscillations of stars) which is expected to be launched in 2025. Further research interests are circumbinary systems and evaporating and disintegrating planets around bright stars.

Contact: Dr Joachim Bestenlehner (j.m.bestenlehner@sheffield.ac.uk) 

13:00, Wednesday 16th May 2018
LT 7, Hicks building