Distinguishing Between Void Models and Dark Energy with Cosmic Parallax and Redshift Drift (2009)
Quartin, Miguel, Amendola, Luca
Two recently proposed techniques, involving the measurement of the cosmic parallax and redshift drift, provide novel ways of directing probing (over a time-span of several years) the background...
Cosmic Parallax as a probe of late time anisotropic expansion (2009)
Quercellini, Claudia, Cabella, Paolo, Amendola, Luca, Quartin, Miguel, Balbi, Amedeo
Cosmic parallax is the change of angular separation between pair of sources at cosmological distances induced by an anisotropic expansion. An accurate astrometric experiment like Gaia could observe...
Viable Singularity-Free f(R) Gravity Without a Cosmological Constant (2009)
Miranda, Vinicius, Joras, Sergio E., Waga, Ioav, Quartin, Miguel
Several authors have argued that self-consistent $f(R)$ gravity models distinct from $\Lambda $CDM are almost ruled out. Confronting such claims, we present a particular two-parameter $f(R)$ model...
Quercellini, Claudia, Quartin, Miguel, Amendola, Luca
Refined astrometry measurements allow us to detect large-scale deviations from isotropy through real-time observations of changes in the angular separation between sources at cosmic distances. This...
Dark Interactions and Cosmological Fine-Tuning (2008)
Quartin, Miguel, Calvao, Mauricio O., Joras, Sergio E., Reis, Ribamar R. R., Waga, Ioav
Cosmological models involving an interaction between dark matter and dark energy have been proposed in order to solve the so-called coincidence problem. Different forms of coupling have been studied,...
Challenges for scaling cosmologies (2006)
Amendola, Luca, Quartin, Miguel, Tsujikawa, Shinji, Waga, Ioav
A cosmological model that aims at solving the coincidence problem should show that dark energy and dark matter follow the same scaling solution from some time onward. At the same time, the model...
Kosterlitz-Thouless transition in three-state mixed Potts ferro-antiferromagnets (2002)
We study three-state Potts spins on a square lattice, in which all bonds are ferromagnetic along one of the lattice directions, and antiferromagnetic along the other. Numerical transfer-matrix are...