Date of Award

Spring 2003

Document Type

Restricted Thesis

Terms of Use

© 2003 Melaku Muluneh. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Physics & Astronomy Department

First Advisor

Amy Lisa Graves


The theoretical lifetime of para-Positronium is calculated using Feynman rules. Relativistic quantum mechanics is discussed. This is accompanied by an introductory level treatment of classical and relativistic propagator theories with the intention of narrowing the gap between relativistic quantum mechanics and quantum electrodynamics, from which the Feynman rules are derived. The Feynman rules are applied to the two possible first order annihilation Feynman diagrams of p-Ps. We obtain a lifetime of 1.25 x 10⁻¹⁰ s for a free Ps. The dependence of the lifetime of positronium on electric field is calculated indirectly by finding the electron-positron overlap integral for Ps placed in electric field. We show that the overlap integral decreases in proportion to E² for electric field values below 0.01 a.u. Our simulation is done using the Path Integral Monte Carlo (PIMC) technique which has been used with success in previous computational studies of Ps.