JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINARS: "Acoustic Black Holes and the Correlations of Hawking Radiation" & "Horizon in Random Matrix Theory, Hawking Radiation and Flow of Cold Atoms"

[statphys]

JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINARS

Lecture Room D - SISSA Main Building

Tuesday, 23 June 2009 - 12:00 hrs

Serena FAGNOCCHI
(S.I.S.S.A. - Trieste)

"Acoustic Black Holes and the Correlations of Hawking Radiation"

Abstract
Hawking radiation in black holes is the most famous and elusive 
prediction of Quantum Field Theory in curved spacetime, but so far no 
experiment is confirming its existence. More fundamental than the theory 
it has been first derived, Hawking radiation has been extended to any 
system able to reproduce the geometrical features of a forming black 
hole specetime: for example in  supersonic flowing fluids the sound gets 
trapped exactly as light in a black hole. Such supersonic flow 
configurations are called "acoustic black holes" and can be  used as 
laboratory to test gravitational effects otherwise undetectable (as 
Hawking radiation). It has been recently proposed how a clear signature 
of the presence of Hawking radiation in acoustic black holes appears in 
the density correlation pattern, analytically obtained using the formal 
analogy between gravitation and hydrodynamics, and numerically confirmed 
in an analysis able to take into account the full microscopic structure 
of the system. In this seminar the main features of the analogy between 
gravitation and hydrodynamics are reviewed. Then the peculiar 
correlation pattern associated to Hawking radiation is showed, and its 
important role to reveal it in near future experiments is underlined.

Tuesday, 23 June 2009 - 12:45 hrs

Fabio FRANCHINI
(ICTP - Trieste)

"Horizon in Random Matrix Theory, Hawking Radiation and Flow of Cold Atoms"

Abstract
We show that the large distance behavior of the density-density 
correlation function of a weakly confined Random Matrix ensemble can be 
exactly reproduced by a Gaussian scalar field theory in a curved 
two-dimensional space-time characterized by the presence of a 
singularity and of an event horizon. Therefore, we propose this as a 
low-energy effective theory describing the ensemble, in analogy to what 
has been done for other invariant ensembles and Luttinger Liquid theory. 
The presence of an event horizon in the curved space-time naturally 
gives rise to a the phenomenon known as Hawking radiation. A similar 
mapping with another gravitational analogue model has been shown to 
exist with a Bose-Einstein condensate pushed to flow at a velocity 
higher than its speed of sound. In this case the Hawking radiation is 
composed of sound waves propagating over the cold atoms. Our work 
suggests a three-fold connection between a moving BEC system, black-hole 
physics and unconventional RMEs.