401 citations · 818 across the 16 of their papers we have counts for
16 papers
Ghost instabilities and strong coupling in quadratic non-metricity theories
Alexander Ganz, Marco Spinelli
We revisit the framework of Newer General Relativity, defined by all independent quadratic invariants of the non-metricity tensor, including the unique quadratic parity-violating t…
Bispectrum from inflation/bouncing Universe in VCDM
Alexander Ganz, Paul Martens, Shinji Mukohyama +1
We discuss the non-linear interactions within the VCDM model, a type II minimally modified gravity model with the same number of degrees of freedom as in General Relativity but not…
Parametric resonance of gravitational waves in general scalar-tensor theories
Yi-Fu Cai, Guillem Domènech, Alexander Ganz +3
Gravitational waves offer a potent mean to test the underlying theory of gravity. In general theories of gravity, such as scalar-tensor theories, one expects modifications in the f…
Disformal symmetry in the Universe: mimetic gravity and beyond
Guillem Domènech, Alexander Ganz
Symmetries play an important role in fundamental physics. In gravity and field theories, particular attention has been paid to Weyl (or conformal) symmetry. However, once the theor…
Bouncing Cosmology in VCDM
Alexander Ganz, Paul Martens, Shinji Mukohyama +1
We construct an asymmetric bouncing scenario within the VCDM model - also known as type-II minimally modified gravity -, a modified gravity theory with two local physical degrees o…
Graviton to Photon Conversion via Parametric Resonance
Robert Brandenberger, Paola C. M. Delgado, Alexander Ganz +1
We study the parametric resonance excitation of the electromagnetic field by a gravitational wave. We show that there is narrow band resonance. For an electromagnetic field in the…
Dynamical Dark Energy in Minimally Modified Gravity
Alexander Ganz
Minimally modified gravity is a class of models with only the two tensor degrees of freedom as in general relativity. Using the framework with auxiliary constraints these models ca…
Cuscuton Inflation
Nicola Bartolo, Alexander Ganz, Sabino Matarrese
We study the impact of (generalized) cuscuton models on standard single scalar field inflation. Generalized cuscuton models are characterized by spatial covariant gravity where a s…
Inflationary epoch in the presence of holographic dark energy
Paola C. M. Delgado, Alexander Ganz, Chunshan Lin
We analyze the effects of the holographic dark energy model in a single field slow-roll inflation, taking into account both the holographic and the dark radiation components. In pa…
Structure Formation in the Effective Field Theory of Holographic Dark Energy
Alexander Ganz, Chunshan Lin
We investigate the structure formation in the effective field theory of the holographic dark energy. The equation of motion for the energy contrast of the cold dark matter is…
Reconsidering the Ostrogradsky theorem: Higher-derivatives Lagrangians, Ghosts and Degeneracy
Alexander Ganz, Karim Noui
We review the fate of the Ostrogradsky ghost in higher-order theories. We start by recalling the original Ostrogradsky theorem and illustrate, in the context of classical mechanics…
Prospects for Fundamental Physics with LISA
Enrico Barausse, Emanuele Berti, Thomas Hertog +318
In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental…
Towards a viable effective field theory of mimetic gravity
Alexander Ganz, Nicola Bartolo, Sabino Matarrese
We discuss mimetic gravity theories with direct couplings between the curvature and higher derivatives of the scalar field, up to the quintic order, which were proposed to solve th…
Testing modified gravity at cosmological distances with LISA standard sirens
E. Belgacem, G. Calcagni, M. Crisostomi +18
Modifications of General Relativity leave their imprint both on the cosmic expansion history through a non-trivial dark energy equation of state, and on the evolution of cosmologic…
Hamiltonian analysis of mimetic scalar gravity revisited
Alexander Ganz, Purnendu Karmakar, Sabino Matarrese +1
We perform the Hamiltonian analysis of several mimetic gravity models and compare our results with those obtained previously by different authors. We verify that for healthy mimeti…
Gravity in mimetic scalar-tensor theories after GW170817
Alexander Ganz, Nicola Bartolo, Purnendu Karmakar +1
We derive the most general mimetic scalar-tensor theory assuming a healthy "seed" action and accounting for the constraints on the speed of gravitational-wave propagation arising f…