Some of my research is done in collaboration with young physicists studying in my department, typically supervising as many as 2 or 3 laurea theses and 2 or 3 PhD theses. I have also done some work with more senior members of my department (L.Gualtieri, A. Melchiorri and, a few years ago, K. Yoshida) and I have several senior collaborators outside my department, presently including A. Grillo, J. Kowalski-Glikman, C. Laemmerzahl, S. Liberati, T.Piran, L. Smolin, J. Stachel, G. Tino.
I still have "a sweet tooth" for grandunification, nonperturbative QCD and finite-temperature field theory but over the last decade or so my research interests have become more and more focused on the study of the "Quantum-Gravity problem", and in particular: Noncommutative spacetimes, Quantum Gravity Phenomenology, Planck-scale modifications of Lorentz symmetry that may be relevant for gamma-ray bursts and UHE cosmic rays, and Deformed Lorentz Symmetry (the so-called ``Doubly Special Relativity"),
selected publications
my paper IJMPD11(2002)35 (item [1] in the reference list here below) introduced the idea of relativistic symmetries "deformed" at the Planck scale, and is ranked 8th most cited among the ~20000 papers published in research area "gr-qc" over these last 15 years
my paper Nature393(1998)763 (item [2] in the reference list here below) initiated the phenomenology research line on on the study of quantum-gravity effects using observations of "gamma-ray bursts", and is ranked 94th most cited among the ~100000 papers published in research area "astro-ph" over these last 15 year
my paper CQG21(2004)3095 (item [3] in the reference list here below) was the first paper on "deformed" symmetries in Loop Quantum Gravity (whereas my original proposal of such deformed symmetries had at first only attracted interest from the side of noncommutative geometry), is ranked 288th most cited among the ~22000 SPIRES-hepth papers of the last 5 years
CV:
7 papers in Nature, 14 papers in Physical Review, 24 papers in NuclearPhysics/PhysicsLetters.....
on some "topcite lists" at SPIRES
1989 "Laurea" degreee from Universita' di Napoli
1993 PhD from Boston University
1993-1995 postodoc at MIT
1995-1997 postdoc at Oxford University
1997-1998 postdoc at University of Neuchatel
1998-2000 Marie Curie postdoctoral Fellow at CERN
since 2000 "Ricercatore" at the Physics Department of the Universita' di Roma "La Sapienza"
notables: Haenny Prize 1999 ("meilleur jeune chercheur en Physique de la Suisse Vaudoise", ~15000 $)
Gravity Researh Foundation, honorable mention, 1998 and 2005
among the winners of the "2008 grant competition of the FQXi Foundation" (65000 $)
research grant from Ateneo della Scienza e della Tecnologia of Univ LaSapienza (2008, ~15000 $)
"premio Napoletani eccellenti nel mondo" (2009; only 6 scientists selected; prizes also awarded to other cathegories)
"premio Sapienza Ricerca" (2009; selected to be one of the 3 scientists presenting their research at a public celebration with Presidente della Repubblica Giorgio Napolitano)
a "popular-science-level description" of some of my recent research results:
The present outmost frontier of fundamental
physics concerns the search of a theory that can
reconcile General Relativity with Quantum Mechanics.These two theories have
shared sovereignity of physics for nearly a century,
both extremely successful in their respective natural
domains of applicability. But there are profound
differences in their logico-mathematical structures.In
the general-relativistic description of gravitational
phenomena observables evolve smoothly and
deterministically.Quantum mechanics, in contrast,
relies on quanta and probabilistic predictions.
Mostly, these differences are moot: The natural realm
of applicability of General Relativity concerns macroscopic
systems, as in the case of the motion of planets within the
solar system, where quantum-mechanics effects are negligibly small;
and {\it vice versa} quantum mechanics governs the properties of
microscopic particles, whose gravitational properties
are far too small to matter. But, while not
easy to access experimentally, these two theories do
allow for a vast regime where they should be both
taken into account, a regime which in particular is
relevant for the understanding of the first instants
of the evolution of the Universe. And when theorists
attempt these analyses that combine General Relativity
and Quantum Mechanics their inadequacy becomes
immediately evident, often taking the shape of
uncurable but clearly unphysical divergences, that
leave experts with the impression of trying to make up
a meaningful picture combining pieces of two different
jigsaw puzzles.
Several scenarios devising a ``quantum gravity", a
unifying theory solving this problem, have been
investigated, but none has produced a fully
satisfactory overall picture and none has found
support in experimental data. All the most studied
scenarios for quantum gravity do predict stikingly new
phenomena, of types that one might immagine naively to
be easily subjectable to experimental scrutiny, but
for the characteristic scale of these new phenomena
the most natural candidate is the gigantic Planck
energy scale Ep (~
1028eV; equivalently describable in terms
of the ultrashort Planck length Lp
~10-35}m) and
this brings the magnitude of the new effects for
regimes that we actually can probe experimentally at
levels that typically are far too small for testing.
An exception to this problem of untestability has
started to be fully appreciated over the last decade[2,4,5,6]:
it has emerged that several previously proposed schemes
for a quantization of spacetime, one of the
most natural implications of quantum gravity, can
affect particle propagation at levels that, while minute
in absolute terms, are within the reach of certain ultrasensitive
experimental studies[2,4,5,6].
For what concerns the formalization of
spacetime quantization I mainly focus on ``spacetime
noncommutativity", a formalism that endows
the spacetime coordinates of particles with intrinsically nontrivial
algebraic properties, whose most studied examples introduce
two model-dependent ``noncommutativity matrices":
I
was one the first advocates of an approach to the
study of noncommutative spacetimes which is centered
on symmetry analysis, searching for both a suitable
formalization[1] and an associated phenomenology
programme[2,6]. (A similar approach
is nowdays also adopted by some research lines within the Loop Quantum Gravity
programme[3]). Of particular interest are cases
in which the symmetries of a noncommutative spacetime
require a Hopf-algebra description. The core
feature of this novel concept of a Hopf-algebra description of
spacetime symmetries resides in the way in
which the generators of the symmetries act on states
of two of more particles, states which are therefore
formalized as elements of a tensor product of multiple copies of the
single-particle Hilbert space. For some of the most
compelling choices of the noncommutativity matrices
one finds an incompatibility between the noncommutativity of spacetime
coordinates and the imposition of Leibniz law for the action of the generators of spacetime symmetries on elements of the relevant
tensor products,
My most significant
recent theory result[7,8,9] consisted in a
generalization of the Noether theorem that is
applicable to the Hopf-algebra symmetries of some of
these noncommutative spacetimes. This had been a
long-standing open issue for physical applications of Hopf-algebra
spacetime symmetries, in which of course the conserved charges derived in
the Noether analysis should play a key role. In
particular, this result allows me to provide a crisper characterization of the
concept of "Planck-scale deformed" spacetime symmetries which I had previously
proposed[1,10] on the basis of a more general analysis of the quantum-gravity
problem.
The scopes of my work on
"quantum gravity phenomenology"[11], with and without issues relevant for
spacetime symmetries, have grown rather sizeably over the last decade, now
including a phenomenology relevant for laser interferometry[4,5,12], some
studies relevant for cosmology[13], a phenomenology focused on neutrino
astrophysics[14], and much more. Presently the most active sources of relevant
data are the Pierre Auger Cosmic ray Observatory and the Fermi Gamma-ray
Telescope, which are relevant for my work on propagation in quantum spacetime[2]
and Planck-scale relativistic kinematics[6]. Perhaps the programme which can be
most easily described non-technically is the one based on observations of gamma
rays by the Fermi Telescope[15]:
gamma-ray bursts are bursts of high-energy
photons emitted by sources at cosmological distances
with a rich structure of space/time/energy
correlations, and the fact
that they travel cosmological distances allows for the minute quantum-spacetime
effects to have in some cases a nonnegligible cumulative effect~[1,3].
A recent development on the phenomenology side of my interests was inspired by theory results establishing that in some noncommutative spacetimes there is a novel effect of ``infrared-ultraviolet mixing". This new scenario, which in just a few years was investigated in several hundred publications, is such that the effects induced by the short-distance quantum structure of spacetime, besides the normally expected implications for the ultraviolet sector of the theory, have implications which are significant in a dual infrared regime. I am now proposing to use the high accuracy of intereferometric techniques applied on ``cold" (ultraslow) atoms as a way to look for signatures of these infrared manifestations of spacetime quantization, and a first study based on this idea produced encouraging results[16].
papers:
[1] Int. J. Mod. Phys. D11 (2002) 35-60, Amelino-Camelia, gr-qc/0012051, "Relativity in space-times with short-distance structure governed by an observer-independent (Planckian) length scale"
[2] Nature 393 (1998) 763-765, Amelino-Camelia G.; Ellis J.; Mavromatos N.E.;Nanopoulos D.V.; Sarkar S., astro-ph/9712103, "Tests of quantum gravity from observations of gamma-ray bursts"
[3] Class.Quant.Grav.21 (2004) 3095-3110, Amelino-Camelia G.; Smolin L.; Starodubtsev A., hep-th/0306134, "Quantum symmetry, the cosmological constant and Planck scale phenomenology"
[4] Nature 398 (1999) 216-218, G. Amelino-Camelia, gr-qc/9808029, "Gravity-wave interferometers as quantum-gravity detectors"
[5] Nature 410 (2001) 1065-1069, G. Amelino-Camelia, gr-qc/0104086, "A Phenomenological description of quantum gravity induced space-time noise"
[6] Phys. Rev. D64 (2001) 036005, G.~Amelino-Camelia and T.~Piran, astro-ph/0008107, "Planck scale deformation of Lorentz symmetry as a solution to the UHECR and the TeV gamma paradoxes"
[7] Mod. Phys. Lett.A22 (2007) 1779-1786, Agostini A.; Amelino-Camelia G.; Arzano M.; Marcian\`o A.; Tacchi R.A,, hep-th/0607221,"Generalizing the Noether theorem for Hopf-algebra spacetime symmetries"
[8] Phys. Rev. D78 (2008) 025005, Amelino-Camelia G.; Briscese F.; Gubitosi G.; Marcian\`o A.; Martinetti P.; Mercati F., arXiv:0709.4600, "Noether analysis of the twisted Hopf symmetries of canonical noncommutative spacetimes"
[9] Phys. Lett. B671 (2009) 298-302, Amelino-Camelia G.; Gubitosi G.; Marcian\`o A.; Martinetti P.; Mercati F., arXiv:0707.1863, "A no-pure-boost uncertainty principle from spacetime noncommutativity"
[10] Nature 418 (2001) 34-35, Amelino-Camelia G., gr-qc/0207049, "Relativity: Special treatment"
[11] Nature 408 (2000) 661-664, G. Amelino-Camelia, gr-qc/0012049, "Quantum theory's last challenge"
[12] Phys.Rev D62 (2000) 024015, G. Amelino-Camelia, gr-qc/9903080, "Gravity-wave interferometers as probes of a low-energy effective quantum gravity"
[13] JCAP 0908 (2009) 021,G. Gubitosi, L. Pagano, G. Amelino-Camelia, A. Melchiorri, A. Cooray, arXiv:0904.3201, "A Constraint on Planck-scale Modifications to Electrodynamics with CMB polarization data"
[14] Nature Physics 3 (2007) 81, G. Amelino-Camelia, "Astroparticle physics: Neutrinos and quantum spacetime"
[15] Nature 462 (2009) 291-292, G. Amelino-Camelia, "Burst of support for relativity"
[16] Phys.Rev.Lett.103 (2009) 171302,G. Amelino-Camelia, C. Laemmerzahl, F. Mercati, G.M. Tino, arXiv:0911.1020, "Constraining the energy-momentum dispersion relation with Planck-scale sensitivity using cold atoms"
Physics Department of the Universita' di Roma "La Sapienza"
Sez.ROMA1 of INFN