My research mainly focuses on the two periods of accelerated expansion that our cosmological observations strongly indicate: Inflation and Dark Energy. Despite the amazing quality of present and forthcoming observations, our knowledge of the Universe is inevitably indirect and the details of the `real theories' of Inflation and Dark Energy (btw, have you ever suspected that they might be the same thing? Don't be ashamed, it happens) may remain elusive for a long time. For these reasons, I intend to follow two main ``strategies":
• Bet on nature being fair, and simple. Among competing theories, there could be an overwhelmingly simple one out there, able to fit all data with just one or two, or even none, adjustable parameters. In parallel with a healthy ‘model building’ activity, we should not give up looking for major conceptual breakthroughs.
• Look for effective descriptions. Nature is not necessarily fair, nor simple. If the ‘real theory’ – of inflation or dark energy – has as many parameters as the Standard Model, we might never be able to discover it nor fit all its parameters. We should therefore develop effective models that are insensitive to the microphysical details.
Papers at PCCP:
1. "The Effective Field Theory of Dark Energy" G. Gubitosi, F. Piazza and F. Vernizzi, arXiv:1210.0201
2. "The Infrared-modified Universe" F. Piazza, arXiv:1204.4099 [gr-qc]]
3. “Relativistic non-relativistic Goldstone theorem: gapped Goldstones at finite charge density” A. Nicolis and F. Piazza, arXiv:1204.1570 [hep-th]
4. “Scalar-tensor theories, trace anomalies and the QCD-frame” F. Nitti and F. Piazza, arXiv:1202.2105 [hep-th]
5. “Spontaneous Symmetry Probing” A. Nicolis and F. Piazza, arXiv:1112.5174 [hep-th] JHEP 1206, 025 (2012)
6. “Eternal inflation and a thermodynamic treatment of Einstein’s equations” J. T. Galvez Ghersi, G. Geshnizjani, F. Piazza and S. Shandera JCAP 1106, 005 (2011) [arXiv:1103.0783 [gr-qc]] SPIRES entry
Selected Papers:
1. “Spontaneous Symmetry Probing” A. Nicolis and F. Piazza, JHEP 1206, 025 (2012) [arXiv:1112.5174 [hep-th]] HEP entry
2. “Sub-eV scalar dark matter through the super-renormalizable Higgs portal” F. Piazza and M. Pospelov Phys. Rev. D 82, 043533 (2010) [arXiv:1003.2313 [hep-ph]]
3. “The IR-Completion of Gravity: What happens at Hubble Scales?” F. Piazza, New J. Phys. 11, 113050 (2009) [arXiv:0907.0765 [hep-th]]
4. “Rapidly-Varying Speed of Sound, Scale Invariance and Non-Gaussian Signatures” J. Khoury and F. Piazza JCAP 0907, 026 (2009) [arXiv:0811.3633 [hep-th]]
5. “Renormalized Thermal Entropy in Field Theory” S. Cacciatori, F. Costa and F. Piazza Phys. Rev. D 79, 025006 (2009) [arXiv:0803.4087 [hep-th]]
6. “Measuring deviations from a cosmological constant: a field-space parameterization” R. Crittenden, E. Majerotto and F. Piazza Phys. Rev. Lett. 98, 251301 (2007) [arXiv:astro-ph/0702003]
7. “Glimmers of a pre-geometric perspective” F. Piazza, Found. Phys. 40, 239 (2010) [arXiv:hep-th/0506124]
8. “Dilatonic ghost condensate as dark energy” F. Piazza and S. Tsujikawa JCAP 0407, 004 (2004) [arXiv:hep-th/0405054]
9. “Model for gravitational interaction between dark matter and baryons” F. Piazza and C. Marinoni Phys. Rev. Lett. 91, 141301 (2003) [arXiv:hep-ph/0304228]
10. “Runaway dilaton and equivalence principle violations” T. Damour, F. Piazza and G. Veneziano Phys. Rev. Lett. 89, 081601 (2002) [arXiv:gr-qc/0204094]
11. “Quintessence as a run-away dilaton” M. Gasperini, F. Piazza and G. Veneziano Phys. Rev. D 65, 023508 (2002) [arXiv:gr-qc/0108016]
