Saul Youssef

Saul Youssef

Research Faculty (Research Associate Professor)

Office Hours: By appointment


Research Interests:

Elementary Particle Physics, Computing, and Quantum Theory

My main research interests include elementary particle physics, computing, and quantum theory.


  • Ph.D. in Physics, Carnegie-Mellon University
  • Postdoc, Columbia University
  • Visiting Fellow, Cornell University
  • Research Associate Professor, Boston University


Principal Investigator, NESE project Principal Investigator, NET2 the U.S. ATLAS Northeast Tier 2 Center Boston University Research Governance Committee Research, Education and Outreach Group, Massachusetts Green High Performance Computing Center

Research Descriptions:

Quantum Mechanics as Exotic Probability

In a series of papers from 1991 through 2001, showed that quantum theory can be replaced by a modified Bayesian probability theory. This results in Real, Complex or Quaternionic versions of quantum mechanics, but without the usual conceptual problems with superposition "non-local effects", EPR issues, etc. A version of this idea seems to have recently appeared as "Quantum Bayesianism". For references, see Saul Youssef, A Reformulation of Quantum Mechanics, Mod.Phys.Lett. A6, 225-236 (1991), Saul Youssef, Quantum Mechanics as Complex Probability Theory, Mod.Phys.Lett A9, 2571 (1994), Saul Youssef, Is Quantum Mechanics an Exotic Probability Theory?, in Fundamental Problems in Quantum Theory; Conference in Honor of Professor John A. Wheeler, ed: D.M. Greenberger and A. Zeilinger, Annals of the New York Academy of Sciences, Volume 755, April, 1995, Saul Youssef, Quantum Mechanics as an Exotic Probability Theory, proceedings of the Fifteenth International Workshop on Maximum Entropy and Bayesian Methods, ed. K.M.Hanson and R.N.Silver, Santa Fe, August, 1995, Saul Youssef, Is Complex Probability Theory Consistent with Bell's Theorem?, Phys.Lett. A204, 181(1995), Saul Youssef, Physics with exotic probability theory, hep-th/0110253, (2001). My 2001 paper is a good place to start.

The ATLAS Experiment at CERN


The ATLAS experiment is a large detector system developed by a collaboration of physicists from around the world to study very-high-energy proton-proton interactions at the Large Hadron Collider (LHC) at CERN, a laboratory for high energy physics near Geneva, Switzerland. Boston University personnel were involved in the construction and installation of the muon detectors for ATLAS. The detectors occupy a region the size of a five-story building and measure the trajectories of muons in a magnetic field with a precision of better than 1/10 of a millimeter. This permits precise determination of the muon momentum which is an important ingredient in searches for new phenomena at the TeV energy scale. Boston University has also played a leading role in the development of computing and analysis tools.