Research Bio.

William Simpson is a PhD student at the University of St. Andrews, Scotland. He completed his MPhys. in Theoretical Physics and Mathematics in June 2010, and joined the Quantum Optics Group at St. Andrews in September 2010. During the last year, he has begun to focus his research on the quantum vacuum (specifically, on Casimir forces in spherically symmetric, inhomogeneous media). He has also founded PhysPhil - a Physics & Philosophy Society.

Prior to this, Mr. Simpson was involved in Solar Physics research. In June 2009, he began an REU internship with the Montana State University Physics Dept. In 2010 he gave a lecture on his research at MSU at the Tomorrow's Mathematicians Today conference in London, and was interviewed by the Institute of Mathematics and its Applications for Peter Rowlett's Travels in a Mathematical World podcast series.

Mr. Simpson has also been involved in research with The Solar Group at St. Andrews. In June 2008, Mr. Simpson began a research project with The Solar Group, which he resumed in 2009-10 for his masters dissertation.

Current Research

William is interested in forces of attraction and repulsion arising from the quantum vacuum. He is currently focussing his efforts on the phenomenon of the Casimir force in spherically symmetric, inhomogeneous media. His recent paper on this subject questions the dismissal of Casimir's semiclassical model of the electron, with its provocative suggestion that fundamental charged particles are held together by the force of the quantum vacuum.

He is also interested in Casimir repulsion. For instance, it is possible to levitate things on 'nothing'. A recent experiment published in Nature has conclusively shown that the normally sticky quantum force of empty space can be turned from attraction to repulsion. In such cases small objects can levitate on the forces of the vacuum, which could be applied in novel micro- and nanomachines.

During the course of his PhD, William hopes to find a better understanding of these fascinating phenomena by modernizing some aspects of a theory that has been stagnant for nearly half a century.

Research Topics

Mr. Simpson's research topics include:

• Forces of the Quantum Vacuum

Publications

Ulf Leonhardt and William M. R. Simpson, Exact solution for the Casimir stress in a spherically symmetric medium.
Phys Rev D, ArXiv

Supervision

Prof. Ulf Leonhardt ulf at st-andrews dot ac dot uk

Fibre-optical black holes; Casimir Forces; Quantum levitation; Invisibility; Quantum catastrophes and Light in moving media