Positrons are the antimatter version of electrons and so their fate in a matter world is ultimately to annihilate. However, prior to this, a positron may combine with an electron to form a matter-antimatter hybrid called positronium. This is akin to a hydrogen atom with the proton replaced by a positron. Fundamental to our understanding of the physical universe, positron and positronium are these days also acknowledged as being fantastically useful in practical applications such as probing material properties and medical diagnostics. However, there is still much that we do not know for sure about the details of the interactions of these particles with ordinary matter. For example if, in a collision with an atom or molecule, a positron captures an electron, in which directions is the positronium likely to travel and with what probability? More...
Published: Jun 17, 2015 12:35:19 PM
How light of different colours is absorbed by carbon dioxide (CO2) can now be accurately predicted using new calculations developed by a UCL-led team of scientists. This will help climate scientists studying Earth’s greenhouse gas emissions to better interpret data collected from satellites and ground stations measuring CO2. More...
Published: Jun 15, 2015 10:29:10 AM
New research from UCL has uncovered additional second laws of thermodynamics which complement the ordinary second law of thermodynamics, one of the most fundamental laws of nature. These new second laws are generally not noticeable except on very small scales, at which point, they become increasingly important. More...
Published: Feb 10, 2015 11:55:53 AM
PhD studentships in Quantum Cavity Optomechanics
The field of optomechanics, in particular the cooling of small mechanical oscillators down to the quantum regime is currently one of the most exciting and rapidly growing areas of physics. This project aims to experimentally reach the quantum regime with optically trapped nanospheres. In addition to the fundamental interest, we seek to make highly sensitive measurements of weak forces at the quantum limit (in other words with a displacement limited only by the width of the ground state of the mechanical oscillator). We are currently exploring cavity cooling of nanoscale polarisable particles in the 100 nm size range which interact strongly with a cavity field, allowing both trapping and cooling by the same field.
The experimental work will be carried out in the group of Professor Peter Barker at the Department of Physics and Astronomy at University College London (UCL). This well resourced group is currently active in cavity optomechanics as well as in cold atoms and molecules research. Further information on the experimental research and publications can be found here.
This is part of a larger project, which has both experimental and theoretical components at UCL (P. Barker and T. Monteiro). The theoretical project will be supervised by Prof. T Monteiro and will involve also simulations of cavity optomechanics with cold atoms and Bose-Einstein condensates. We collaborate with J. Ruostekoski at the University of Southampton and with project-partners at the University of Nuremberg-Erlangen and at Princeton University.
Funding for PhD stipend and university fees are available for up to 4 years to EU/UK students.
Please contact Professor Peter Barker at P.Barker@ucl.ac.uk for further information.