Project description
From two to many; novel theoretical descriptions to have a positive impact on particle physics
Most of us are familiar with lithium, sodium and potassium, but likely far fewer people have heard of positronium. The existence of this exotic 'atom' with no nucleus has been known for decades. Like a hydrogen atom that consists of one electron and one proton, a positronium consists of a negatively charged electron bound to a positively charged positron (the charged antiparticle of the electron). These 'atoms' are unstable, and their particles annihilate each other in fractions of a second, emitting gamma rays. Understanding the interactions of positrons and positronium with other matter is critical to fields ranging from astrophysics to medicine. The EU-funded ANTI-ATOM project is developing the complex theory required to describe these behaviours with models that will support the optimised design of experiments and interpretation of results.
Objective
The ability of positrons to annihilate with electrons, producing characteristic gamma rays, gives them important use in medicine via positron-emission tomography (PET), diagnostics of industrially-important materials, and in elucidating astrophysical phenomena. Moreover, the fundamental interactions of positrons and positronium (Ps) with atoms, molecules and condensed matter are currently under intensive study in numerous international laboratories, to illuminate collision phenomena and perform precision tests of fundamental laws.
Proper interpretation and development of these costly and difficult experiments requires accurate calculations of low-energy positron and Ps interactions with normal matter. These systems, however, involve strong correlations, e.g. polarisation of the atom and virtual-Ps formation (where an atomic electron tunnels to the positron): they significantly effect positron- and Ps-atom/molecule interactions, e.g. enhancing annihilation rates by many orders of magnitude, and making the accurate description of these systems a challenging many-body problem. Current theoretical capability lags severely behind that of experiment. Major theoretical and computational developments are required to bridge the gap.
One powerful method, which accounts for the correlations in a natural, transparent and systematic way, is many-body theory (MBT). Building on my expertise in the field, I propose to develop new MBT to deliver unique and unrivalled capability in theory and computation of low-energy positron and Ps interactions with atoms, molecules, and condensed matter. The ambitious programme will provide the basic understanding required to interpret and develop the fundamental experiments, antimatter-based materials science techniques, and wider technologies, e.g. (PET), and more broadly, potentially revolutionary and generally applicable computational methodologies that promise to define a new level of high-precision in atomic-MBT calculations.
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Funding Scheme
ERC-STG - Starting GrantHost institution
BT7 1NN Belfast
United Kingdom