François Englert

François Englert (born 6 november 1932) is a Belgian theoretical physicist. He was awarded, with Robert Brout and Peter Higgs, the High Energy and Particle Prize of the European Physical Society in 1997 and the Wolf Prize in Physics in 2004 for the mechanism which unifies short and long range interactions by generating massive gauge vector bosons. He made significant contributions in statistical physics, quantum field theory, cosmology, string theory and supergravity. [ [http://homepages.ulb.ac.be/~fenglert/publi.pdf Publication list] ]

Academic career

He graduated as electrical-mechanical engineer in 1955 from the Université Libre de Bruxelles (ULB) where he got his PhD in physical sciences in 1959. From 1959 until 1961, he worked at Cornell University, first as research associate of Robert Brout and then as assistant professor. He then returned to the ULB where he became a university professor and was joined there by Robert Brout. From 1980 they coheaded the theoretical physics group. In 1998 Englert became emeritus.

The Brout-Englert-Higgs mechanism

Brout and Englert showed in 1964 [F. Englert and R. Brout "Phys.Rev.Lett." 13 321 (1964).] that gauge vector fields, abelian and non-abelian, could acquire mass if empty space were endowed with a particular type of structure that one encounters in material systems. Focusing on the failure of the Goldstone theorem for gauge fields [P. W. Higgs "Physics Letters" 12 132 (1964).] , Higgs reached essentially the same result [P. W. Higgs "Phys.Rev.Lett." 13 508 (1964).] . A third independent paper on the subject was written at the same time by Gerald Guralnik, C. R. Hagen, and Tom Kibble [cite web|url=http://prola.aps.org/abstract/PRL/v13/i20/p585_1|title=Global Conservation Laws and Massless Particles] . The three papers written on this boson discovery by Higgs, Englert and Brout, and Guralnik, Hagen, Kibble were each recognized as milestone papers for this discovery by Physical Review Letters 50th anniversary celebration. [ [http://prl.aps.org/50years/milestones Physical Review Letters - 50th Anniversary Milestone Papers] ]

To illustrate the structure, consider a ferromagnet which is composed of atoms each equipped with a tiny magnet. When these magnets are lined up, the inside of the ferromagnet bears a strong analogy to the way empty space can be structured. Gauge vector fields that are sensitive to this structure of empty space can only propagate over a finite distance. Thus they mediate short range interactions and acquire mass. Those fields that are not sensitive to the structure propagate unhindered. They remain massless and are responsible for the long range interactions. In this way, the mechanism accommodates within a single unified theory both short and long-range interactions.

Brout and Englert, Higgs, and Gerald Guralnik, C. R. Hagen, and Tom Kibble introduced as agent of the vacuum structure a scalar field (most often called the Higgs field) which many physicists view as the agent responsible for all masses in the universe. Brout and Englert also showed that the mechanism may remain valid if the scalar field is replaced by a more structured agent such as a fermion condensate. Their approach led them to conjecture that the theory is renormalizable ["Fundamental Problems in Elementary Particle Physics", Proceedings of the 14th Solvay Conference, University of Brussels, 2-7 October 1967 (John Wiley, New York, 1968) page 18.] . The eventual proof of renormalizability, a major achievement of twentieth century physics, is due to Gerardus 't Hooft and Martinus Veltman who were awarded the 1999 Nobel Prize for this work. The Brout-Englert-Higgs mechanism is the building stone of the electroweak theory of elementary particles and laid the foundation of a unified view of the basic laws of nature.

Major scientific awards

*1978 First Prize in the International Gravity Contest (with R. Brout and E. Gunzig), awarded by the Gravity Research Foundation for the essay "The Causal Universe". [ [http://www.gravityresearchfoundation.org/winners_year.html#98 Gravity Research Foundation Awards] ]

*1982 Francqui Prize, awarded by the Francqui Foundation once every four years in exact sciences "For his contribution to the theoretical understanding of spontaneous symmetry breaking in the physics of fundamental interactions, where, with Robert Brout, he was the first to show that spontaneous symmetry breaking in gauge theories gives mass to the gauge particles, for his extensive contributions in other domains, such as solid state physics, statistical mechanics, quantum field theory, general relativity and cosmology, for the originality and the fundamental importance of these achievements".

*1997 High energy and particle physics Prize (with R. Brout and P.W. Higgs), awarded by the European Physical Society "For formulating for the first time a self-consistent theory of charged massive vector bosons which became the foundation of the electroweak theory of elementary particles". [ [http://www.eps.org/activities/eps-prizes/activities/eps-prizes/high-energy-and-particle-physics-prize EPS High Energy Prize Laureates] ]

*2004 Wolf Prize in Physics (with R. Brout and P.W. Higgs), awarded by the Wolf Foundation "For pioneering work that has led to the insight of mass generation, whenever a local gauge symmetry is realized asymmetrically in the world of sub-atomic particles".

References