Relativistic statistical mechanics and hydrodynamics
Statistical mechanics and fluid dynamics in the relativistic regime present new and intriguing theoretical problems and features, which are usually disregarded or unimportant in the usual non-relativistic limit. The very definition of otherwise familiar concepts, such as particle density, pressure, temperature becomes non-trivial. A relativistically consistent - especially in the quantum regime - formulation of hydrodynamics is highly non-obvious and it has been recently drawn much attention. A relevant issue is the role and the definition of the local entropy current and the second law of thermodynamics, which plays a major role in defining causally consistent extensions of dissipative relativistic hydrodynamics, but which has no counterpart in local quantum field theory.
In the past years, we have investigated the role and the effect of spin degreees of freedom in the general formulation of relativistic hydrodynamics and relativistic kinetic theory taking a first-principle formulation based on quantum field theory.
We are currently studying quantum corrections to the form of the stress-energy tensor in local thermodynamical equilibrium and its consequences.
At the same time, we are developing a 3+1D numerical code for relativistic dissipative hydrodynamics in collaboration with INFN Ferrara and Torino, ECHO-QGP (see Ongoin Projects).
In the past years, we have investigated the role and the effect of spin degreees of freedom in the general formulation of relativistic hydrodynamics and relativistic kinetic theory taking a first-principle formulation based on quantum field theory.
We are currently studying quantum corrections to the form of the stress-energy tensor in local thermodynamical equilibrium and its consequences.
At the same time, we are developing a 3+1D numerical code for relativistic dissipative hydrodynamics in collaboration with INFN Ferrara and Torino, ECHO-QGP (see Ongoin Projects).
Quark Gluon Plasma and relativistic heavy ion collisions
In very high energy collisions of heavy nuclei (currently ongoing at the LHC collider at CERN) quarks and gluons are released from their hadronic bounds and a new state of matter is formed, the so-called Quark-gluon plasma, at astoundingly large values of temperature (several TeraKelvin), pressure and density, by far the largest ever reached in a terrestrial laboratory, in a domain where relativistic effects are prevailing. The transition from hadronic matter, where protons, neutrons and other hadrons, are individual particles to the quark-gluon plasma phase is a definite prediction of the theory of strong interactions, quantum chromodynamics and it is supported by numerical calculations (lattice QCD). In high energy collisions of heavy nuclei, the plasma lives only for 10-22 sec because its rapid expansion cools it and gets it back to the hadronic phase.
We investigate the properties of the plasma phase by studying many features of the hadrons emitted in high energy collisions of nuclei and particularly the multiplicities of the various hadronic species, the production of strange quarks, as well as their spectra and polarization. This is done with both analytical calculations, whenever possible, and numerical codes. |
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Hadronization in high energy collisions
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In high energy collisions of elementary particles or nuclei we always observe many hadrons in the final state, even though the quantum field theory of strong interactions (QCD) has quarks and gluons as fundamental degrees of freedom. This phenomenon (confinement) is related to the nature of QCD as a strongly interacting non-perturbative theory at large distances (1 fm) and small energy scale (around 1 GeV). The process of hadron formation at large distance scale is called hadronization and it cannot presently be reckoned with ab initio QCD calculations, neither analytical nor numerical. However, its properties can be investigated with the help of models. An intriguing feature of hadronization is that particle multiplicities and spectra, in the low momentum region, can be succesfully reproduced to a high level of accuracy with an equilibrium statistical mechanical calculation (statistical hadronization model). The statistical equilibrium is an emergent feature of QCD in the strong non-linear regime which has not been understood yet.
We have worked on this model for many years, contributing to its development and showing its capabilities of reproducing multiplicities, multiplicity distributions, transverse momentum spectra and even exclusive rates in many research papers. |
Publications
Read the list of publications here (inSPIRE HEP).
Ongoing Projects
ECHO-QGP: a code for relativistic dissipative hydrodynamics in 3+1 D
We are working on a code for numerical calculations in relativistic hydrodynamics with dissipative corrections in 3+1 dimensions aimed at relativistic heavy ion collisions, ECHO-QGP. This code is a development of a code originally designed for astrophysical plasmas. Our collaboration involves groups in Firenze, Ferrara (A. Drago, G. Pagliara and V. Rolando) and Torino (A. Beraudo, A. De Pace, M. Nardi). The code is publicly available here.
The code successfully reproduces analytical solutions of both ideal hydrodynamics and dissipative Israel-Stewart theory, notably the Gubser flow test.
The code successfully reproduces analytical solutions of both ideal hydrodynamics and dissipative Israel-Stewart theory, notably the Gubser flow test.