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
Professor Ferruccio Renzoni
+44 (0) 20 7679 7019
Ferruccio Renzoni studied Physics at the University of Pisa (Italy) where he obtained his M.Sc. in 1993. He obtained his Ph.D. from the Technische Universitaet Graz (Austria) in 1998. He then spent two years in Germany, at the Institut fuer Laserphysik of the University of Hamburg, and three years in France, at the Laboratoire Kastler Brossel (Ecole Normale Superieure, Paris), where he obtained his "Habilitation a diriger des recherches". Since 2003 he has been at the Department of Physics and Astronomy of the University College London.
Ferruccio's current research interests include the study of nonlinear dynamics in driven systems and the development of novel imaging techniques. Current research projects are:
Magnetic Induction Tomography with Atomic Magnetometers
Magnetic induction tomography (MIT) is a non-contact and non-destructive electromagnetic imaging technique, that has potential applications in security, industry, medicine and geophysics. MIT principles rely on the establishment of eddy currents in a conductive object, and the detection of the magnetic field generated by these currents.
The ultimate performance of a magnetic induction tomography system depends on the magnetic field sensor used. Standard coil sensors show poor sensitivity at low frequency and low resolution. Ferruccio's team recently demonstrated that Magnetic Induction Tomography can be performed with atomic magnetometers, which have record sensitivity at low frequency and offer promise of extreme resolution. This paves the way to a wealth of new applications of magnetic imaging, from the medical to the security sectors.
 A. Wickenbrock, F. Tricot, and F. Renzoni, Magnetic induction measurements using an all-optical 87Rb atomic magnetometer, Appl. Phys. Lett. 103, 243503 (2013).
 A. Wickenbrock, S. Jurgilas, A. Dow, L. Marmugi, F. Renzoni, Magnetic induction tomography using an all-optical 87Rb atomic magnetometer, Opt. Lett. 39, 6367 (2014).
Sub-Fourier signal processing with non-linear systems
A linear system is able to distinguish two frequencies f1 and f2 in a time 2*pi/|f1-f2|. This is not necessarily true for nonlinear systems, which can distinguish frequencies in a time shorter than the Fourier limit. This is of interest for efficient information processing.
The project aims to understand the foundations of sub-Fourier signal processing, both theoretically and experimentally. Theoretical work already highlighted some important features of sub-Fourier resonances in non-linear systems . These predictions are currently being experimentally tested with nonlinear quantum optical systems.
 D. Cubero, J. Casado-Pascual, and F. Renzoni, Irrationality and Quasiperiodicity in Driven Nonlinear Systems, Phys. Rev. Lett. 112, 174102 (2014).
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