Théorie

Interactions between inclusions in fluid two-dimensional membranes

Biological membranes are fluid surfaces with an elastic Hamiltonian function of the local curvature, mean and Gaussian. Proteins, that are included in such surfaces, deform them, and interact via the deformation they create. Since membranes exhibit large thermal fluctuations, these interactions have a 'Casimir' character. Proteins can be out-of-equilibrium objects actively changing conformation, while the membrane in which they live exhibit a complex dynamics ruled by the bilayer structure of the membrane. Proteins thus experience nontrivial dynamical interactions.

The new relationship between inflation and gravitational waves

 It is well known that the amplitude of the gravitational wave (GW) produced from the vacuum fluctuation during inflation is proportional to the energy scale of inflation. Thus the observation of the inflationary GW by CMB B-mode is expected to reveal the energy scale of new physics as well as pin down the inflation model. However, alternative production mechanisms of GW during inflation has been discussed recently. We consider a coupled system between an axion and SU(2) gauge fields whose energy density is subdominant.

Observational constraints and Bayesian model comparison in non-local gravity

I present the cosmological predictions of two non-local modifications of General Relativity recently proposed by our group, the so-called RT and RR models. Both models have the same number of parameters as Lambda-CDM, with a mass parameter m replacing the cosmological constant. In implementing their cosmological background and perturbations equations into the CLASS Boltzmann code, we constrain the non-local models using the Planck 2015, isotropic and anisotropic BAO, JLA supernovae, H_0 measurements and growth rate data.

Classical & Quantum Black Hole Hair from Goldstone Modes

Although there is direct experimental evidence for the existence of black holes from the recent measurements of gravitational waves,  black holes are still mysterious objects from the theoretical point of view. According to the seminal work of Stephen Hawking, all information about the collapsing matter that forms a black hole is lost during the evaporation of Hawking radiation. This loss of information is in sharp conflict with the rules of quantum mechanics.

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