Ali Chamseddine

Ali H. Chamseddine is a Lebanese^[2] physicist known for his contributions to particle physics, general relativity and mathematical physics.^[3][4] As of 2013, Chamseddine is a physics Professor at the American University of Beirut and Institut des Hautes Études Scientifiques.

Research

Chamseddine's research revolves around non-commutative geometry in particle physics as well as supergravity theory.^[5] He is perhaps best known for the construction of a realistic model of particle interactions within the N = 1 supergravity framework where supersymmetry (SUSY) is broken by a super Higgs mechanism, carried out by Ali Chamseddine, Richard Arnowitt and Pran Nath in 1982.^[6][7] In these classes of models collectively now known as minimal supergravity Grand Unification Theories (mSUGRA GUT), gravity mediates the breaking of SUSY through the existence of a hidden sector.^[8]

Chamseddine frequently works with cited Fields Medalist Alain Connes on non-commutative geometry.^[9] One of the work done between the two is the so-called "Spectral Action Principle". In this paper, Chamseddine and Connes propose a new action principle to be associated with a non-commutative space (A, H, D). The universal formula for the spectral action is (ψ, Dψ) + Trace(χ(D/Λ)) where ψ is a spinor on the Hilbert space, Λ is a scale and χ a positive function. When this principle is applied to the non-commutative space defined by the spectrum of the standard model, one obtains the standard model action coupled to Einstein plus Weyl gravity. There are relations between the gauge coupling constants identical to those of SU(5) as well as the Higgs self-coupling, to be taken at a fixed high energy scale.^[10] Moreover, on August 2013, Chamseddine and Viatcheslav Mukhanov proposed a new model to describe the effect of Dark Matter, the model is called "Mimetic Dark Matter". In this model, Chamseddine and Mukhanov represented the effect of dark matter as a purely geometrical one coming from splitting the metric of spacetime into an auxiliary metric, which keeps the physical metric invariant under conformal transformations, and the derivative of a scalar field φ. After solving for the equations of motion, a tensor that resembles the Stress-Energy tensor of dust comes out of the equations, even in the absence of normal matter. This tensor represents the effect of Cold Dark Matter. The results are published in ^[11] and in ^[12]

Life

Ali H. Chamseddine was born in 1953 in the town of Joun, Lebanon located in Mount Lebanon.
He received his B.Sc in Physics from the Lebanese University in July 1973 with high distinction. After receiving a scholarship from the Lebanese University to continue his graduate studies in Physics at Imperial College London, Chamseddine received a Diploma in Physics in June 1974, under the supervision of T.W.B. Kibble. After that, Chamseddine did his PhD in Theoretical Physics at Imperial College London as well, in September 1976, where he studied under Nobel Prize Winner Abdus Salam as his Thesis Adviser, with thesis title "Supersymmetry and Higher Spin Fields".^[9][13] Chamseddine did his Postdoctoral studies at the Abdus Salam international center for theoretical Physics(ICTP).^[9][13] Chamseddine worked at Northeastern University, where he came up with the mSUGRA model with Nath and Arnowitt, ETH Zurich, CERN and the American University of Beirut, where he was the Founding Director of the Center for Advanced Mathematical Sciences in February 1998. Chamseddine served as the head of the center until 2003. During this time, Chamseddine was able to enhance the mathematical research in Lebanon through numerous amounts of seminars, conferences, in addition to hosting some great figures of the scientific community such as Murray Gell-Mann, Michael Atiyah and many other scholars.^[14]
In September 2004, he took part in a CERN meeting for the dicussion of future collaborations with countries across Europe.^[15]

References

^[16]

External links

• Google Scholar report