The physics of Rodolfo Gambini

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The physics of Rodolfo Gambini
Jorge Pullin Horace Hearne Laboratory for
Theoretical Physics Louisiana State University
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Rodolfo has written more than 110 refereed
papers, with more than1700 citations and over 16
contributions to proceedings. It is therefore
impossible to summarize this body of work within
a talk. I will concentrate on papers that the
audience is likely to be unfamiliarwith, in
particular I will almost not mention at all the
joint work we have done.
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Rodolfo was the first person to get a physics
degree (Licenciado) inUruguay in February 1972.
He submitted his first paper on June 9th
1972. Spires lists it as the sixth physics paper
in history to be submitted from Uruguay.
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So they wrote an action for the conformal field
and then usedit to conformalize the action of
a tensor field. Sort of like treatinggravity as
in Nordstroms theory and coupling a tensor field
to it.They did a canonical analysis of the
linearized equations and found that the
constraint structure led to inconsistencies.
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Rodolfo then left Uruguay and went to France to
complete a Ph.D.under the supervision of Achille
Papapetrou. On gravitational wave detection!!
The paper wassubmitted afterRodolfo leftFrance
and wason the facultyat the SimonBolivar
Universityin Venezuela.
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Canonical analysis of a 22 formulation in terms
of tetrads, in whicha natural energy density can
be defined. Several of the variables endup being
closely connected with Newman-Penrose scalars.
The energydensity is a multiple of t. The null
energy can be obtained as a surfaceintegral.
Rodolfo kept an interest in null formulations
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In 1980 loops arrive in the scene
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Which led to the well known papers,
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tHooft -gt Similar ideas but for lines of
magnetic flux (another phase). Order parameter
B.
Wilson -gt W exp(-l) not confining
W exp(-a) confining W can be seen as
an order parameter.
In this paper operator is implemented in the
loop representation, is related to the Gauss
linking number.
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Rather different than future treatments of
supersymmetry with loops,it uses loops in
superspace and defines a suitable notion of
groupof hoops (in modern terminology) that
implements the supersymmetry constraints in a
natural way.
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C. Di Bartolo, RG, L. Leal, PRD39, 1756(1989)
U(1), SU(2) in Hamiltonian form.C. Di Bartolo,
RG, A. Trias PRD39, 3136(1989) Z2
theory. Several other more
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Anyons
Fermi-Bose
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The correct way to write Makeenko-Migdal type
equationsis in terms of the loop derivative.
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Surface representation for antisymmetric tensor
fields, anidea that Lee Smolin used extensively
in the late 90s when trying to get strings
from loop quantum gravity.
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Then this happened
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From here on many well known things happened

• Jones polynomial as a state of quantum gravity.
• The extended loop representation.
• Vassiliev invariants as an arena for quantum
  gravity.
• Nonstandard optics.
• Relational descriptions.
• Expansions in the inverse of the cosmological
  constant.
• Consistent and uniform discretizations.
• Decoherence from quantum gravity.

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Two last things
Spin foams!
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Conclusions

• Happy birthday Rodolfo!
• Thanks for a lot of great science!
• May a lot more great science happen inthe future!