San Diego State University - Minds That Move the World

Fridolin Weber, PhD, PhD habil, MS

Distinguished Professor of Physics


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Associate Chair
Graduate Advisor for Physics and Medical Physics

Diplom (Master Science) in Theoretical Physics, Ludwig Maximilian University (LMU), Munich, Germany
Ph.D. in Theoretical Nuclear Physics, LMU
Ph.D. habil. in Theoretical Astrophysics, LMU

Department of Physics, San Diego State University, 5500 Campanile Drive
San Diego, California 92182, USA; Phone: (619) 594 0239, Fax: (619) 594 5485,

Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, California 92093, USA; Phone: (858) 822 3435, Email:

Research Interest

Superdense matter. My research focuses on the theoretical exploration of the properties of strongly interacting matter at ultra-high densities (10 to 20 times denser than atomic nuclei) and temperatures (several hundred billion degrees). Experimentally, the properties of such matter are being probed with the Relativistic Heavy Ion Collider RHIC at Brookhaven and the Large Hadron Collider (LHC at Cern). Great advances in our understanding of such matter are expected from the next generation of heavy-ion collision experiments at FAIR (Facility for Antiproton and Ion Research at GSI) and NICA (Nucloton-bases Ion Collider fAcility at JINR). The long sought after quark gluon plasma (hot QCD matter) was created for the first time at RHIC in 2000. Since then the RHIC physics program has successfully measured or bracketed parameters that are of fundamental physical importance for our understanding of hot QCD (Quantum Chromo Dynamics) matter.

Neutron stars, quark stars, supernovae and gamma-ray bursts. Theoretically, it is understood that the universe was filled with super-dense matter shortly after the Big Bang, is being created in the final stages of catastrophic stellar events (core-collapse supernovae, gamma-ray bursts), and exists deep inside the cores of collapsed stars, know as neutron stars. Neutron stars are dense, neutron-packed remnants of massive stars that blew apart in supernova explosions. They are typically about 10 kilometers across and spin rapidly, often making many hundred rotations per second. Many neutron stars form radio pulsars, emitting radio waves that appear from the Earth to pulse on and off like a lighthouse beacon as the star rotates at very high speeds. Neutron stars in X-ray binaries accrete material from a companion star and flare to life with tremendous bursts of X-rays. Depending on mass and rotational frequency, gravity compresses the matter in the core regions of neutron stars to densities that are 10 to 20 times higher than the density of ordinary atomic nuclei. A thimble full of neutron star matter would have a mass of one billion tons! At such extraordinary densities atoms themselves collapse, and atomic nuclei are squeezed so tightly together that new fundamental particles are generated and novel states of matter are created. The most spectacular phenomena stretch from the creation of novel particles (hyperons and/or delta particles), to boson condensates, to quark matter. The interest in the physics and astrophysics of quark matter has recently received an additional boost from the discovery that quark matter ought to be a superconductor, which would have very intriguing consequences for numerous astrophysical phenomena. There is also the very intriguing theoretical suggestion of E. Witten (Princeton) that neutron stars may be made up of absolutely stable strange quark matter, a configuration of matter even more stable than the most stable atomic nucleus, 56Fe, which, if true, would turn our understanding of neutron stars upside down.  [Read more]