TODAY: ICTP Colloquium - Wednesday 19 July 2017: "The Dynamics of the Gravitational Constant G", by Prof. Claudio Bunster

[ICTP Director]

Dear All,

ICTP is pleased to announce the ICTP Colloquium, *"The Dynamics of the 
Gravitational Constant G", by Prof. Claudio Bunster *(Centro de Estudios 
Cientificos (CECs) Valdivia, Chile, which will take place *today,  
Wednesday  19 July at 16:30 hrs*, in the Budinich Lecture Hall, Leonardo 
Building, ICTP.

*BIOSKETCH:* Theoretical physicist Claudio Bunster was born in Santiago, 
April 15, 1947, under the name Claudio Teitelboim, which he maintained 
until 2005. Educated at Universidad de Chile and Princeton University, 
Bunster has taught at Princeton, the University of Texas at Austin and 
Universidad de Chile and has been a long-term member at the Institute 
for Advanced Study, Princeton. He was awarded the Chilean National 
Science Prize in 1995 and was elected foreign associate of the United 
States National Academy of Sciences in 2005. Bunster's first interest in 
theoretical physics was the problem of radiation reaction in classical 
electrodynamics, where he found a new splitting of the energy momentum 
tensor of the electromagnetic field of a classical point charge in two 
separately conserved pieces. This led to a reinterpretation of the 
Lorentz-Dirac equation of motion. Then his attention turned to general 
relativity, where he elucidated the Hamiltonian structure of spacetime, 
giving a geometrical meaning to the commutation relations of the 
generators of hypersurface deformations. Among the results of his 
subsequent research, one may find, for example, significant 
contributions to: the determination of the role of surface integrals as 
generators of asymptotic symmetries in general relativity and gauge 
theories, the understanding of the quantum numbers of a black hole and 
its thermodynamics, the theory of black holes in lower dimensions, the 
general theory of constrained systems and its quantization, the dynamic 
neutralization of the cosmological constant, and the generalization of 
the notion of electric-magnetic duality to extended objects and higher 
spins. Bunster has been the Director of the Centro de Estudios 
Científicos (CECs) since its foundation in 1984. Besides its work as 
Director and his research activity in theoretical physics, Bunster has 
been involved in public service. He served as Presidential Science 
Advisor in President Eduardo Frei’s administration (1994-2000). During 
his tenure as science advisor the Presidential Science Chairs and the 
Millennium Science Initiative were established. He was also a member of 
the Dialogue Board on Human Rights (Mesa de Diálogo sobre Derechos 
Humanos), established by the Government to address pending human rights 
problems, with the participation of civilians and the military.

*ABSTRACT*:The issue of the enormously small value that the 
gravitational constant G takes when expressed in microscopical units is 
revisited. A simple mechanism is discussed, which could implement 
Dirac's idea of G actually decaying; from an initial value commensurable 
with microscopical units to its value in the present epoch of the 
universe. The mechanism is based on the possibility of having, within 
one universe, domains with different values of G, whose borders are 
crossed by particles and forces. The dynamics of the novel kind of 
domain wall that separates two such dominions is largely dictated by the 
second law of thermodynamics as applied to a black hole. It is argued 
that this is a satisfactory state of affairs, since the expression of 
the entropy of a black hole is the formula in physics where all the 
constants characterising its different realms appear together in a 
poignant manner.

More information at: http://indico.ictp.it/event/8271/

The Colloquium will be livestreamed at http://video.ictp.it/livestream

The poster is attached.

Light refreshments will be served after the lecture.

You are all very warmly invited to attend.

Fernando Quevedo