Zvi Bern

Zvi Bern is an American theoretical particle physicist . He is a professor at the University of California, Los Angeles (UCLA).

Life

Bern studied physics and mathematics at the Massachusetts Institute of Technology (bachelor's degree) and received his doctorate in theoretical physics in 1986 from the University of California, Berkeley under Martin Halpern .

Bern developed new methods of calculating Feynman diagrams , which were originally introduced for quantum electrodynamics for the perturbation-theoretical calculation of scattering amplitudes. In more complicated quantum field theories such as Yang-Mills theories or field theories with gravity, the perturbative development ( Feynman diagrams ) quickly reached its limits due to the large number of diagrams to be taken into account, even for supercomputers. The new theoretical developments of the 1990s and 2000s prompted a newly awakened interest in extensive calculations as part of the experiments on the Large Hadron Collider . The techniques introduced by Bern and colleagues (for example based on the use of twistors and new or generalized unitarity methods ) provided, for example, in 2005 new insights into the perturbative treatment of N = 8 supergravity and showed that there are fewer divergences than expected ( on the 1-loop level as many as with N = 4 Super-Yang-Mills theory). Before that it was generally assumed that from three loops onwards, quantum gravity led to divergences that were no longer controllable. In 2010, with his students Carrasco and Johansson, he found that diagrams for (supersymmetric) gravity theories are equivalent to those of two copies of (supersymmetric) Yang Mills theories (theories with gluons ). They used a previously found duality between kinematics and degrees of color freedom. Instead of around terms previously , only 10 terms had to be evaluated in 3 loops and accordingly around 100 terms in 4 loops and around 1000 instead of evaluated in 5 loops , and there were no untamable divergences in three and four loops , which we believe was predicted by the majority of experts in the 1980s and was one of the reasons for preferring string theories . ${\displaystyle 10^{20}}$ ${\displaystyle 10^{26}}$ ${\displaystyle 10^{31}}$

2014 he was with David A. Kosower and Lance J. Dixon the Sakurai Prize for pioneering studies on perturbative calculation of scattering amplitudes to a deeper understanding of quantum field theory and powerful new tools for calculating processes of quantum chromodynamics led .

He received an Outstanding Young Investigator Award from the Department of Energy and was a Sloan Research Fellow in 1993 and a Fellow of the American Physical Society in 2004 .

Fonts

• Bern, Dixon, Kosower Quantum Gravity Particles may resemble ordinary particles of force , Scientific American, May 2012
• Bern, John Joseph Carrasco, Henrik Johansson Progress on UV finiteness of Supergravity , Erice Lectures 2008
• Bern, Carrasco, Johansson New relations for gauge theory amplitudes , Physical Review D, 78, 2008, 085011
• Bern, Carrasco, Johansson Perturbative quantum gravity as a double copy of gauge theory , 2010
• Bern, Carrasco, Johansson The Structure of Multiloop Amplitudes in Gauge and Gravity Theories , in Loops and Legs in Quantum Field Theory , Woerlitz 2010, Nucl. Phys. Proc. Suppl. 205-206, 2010, pp. 54-60
• Bern, Dixon, Kosower On shell methods in perturbative QCD , Annals of Physics, 322, 2007, 1587-1634
• Bern, Dixon, Kosower Progress in 1 loop QCD calculations , Annual Review Nuclear Particle Physics, 46, 1996, 109-148
• Bern Perturbative Quantum Gravity and its relation to Gauge Theory , Living Reviews of Relativity, 2002

Web links

• Homepage
• Video from Bern, Feynman Diagram: Past, Present, Future, UCLA, 2011

Individual evidence

1. ↑ Zvi Bern in the Mathematics Genealogy Project (English)
2. ↑ Bern, Yu-tin Huang Basis of generalized unitariy , Arxiv 2011
3. ↑ Bern, Dixon, Roiban Is N = 8 Supergravity Ultraviolet Finite? , Phys. Letters B 644, 2007, 265-271
4. ↑ Laudation Sakurai Prize