The Arrogant Eye and the French Prohibition of the Veil

Evânia Reich presents the argument that the veil laws in France—the banning of the full-face coverings in public and the banning of the headscarf in public schools—are consistent with the emancipatory project of French Laïcité. According to this argument, the veils that Muslim women wear are symbols of their oppression, whereas French education seeks to liberate each individual and Laïcité serves as a bulwark against the creeping oppressive influence of religion. Unveiling Muslim women, then, is an act of emancipation. In this essay, I argue that the view of French secularism as an emancipatory project to free women of the oppressive mechanism of the veil is an example of what Marilyn Frye calls the “arrogant eye.” In this essay, I offer an alternative approach on the veil following Frye’s notion of the “loving eye.

Comments on Challenges for Quantum Gravity

We examine radiative corrections arising from Lorentz violating dimension five operators presumably associated with Planck scale physics as recently considered by Myers and Pospelov. We find that observational data result in bounds on the dimensionless parameters of the order $10^{-15}$. These represent the most stringent bounds on Lorentz violation to date

Dark energy from quantum gravity discreteness

We argue that discreteness at the Planck scale (naturally expected to arise from quantum gravity) might manifest in the form of minute violations of energy-momentum conservation of the matter degrees of freedom when described in terms of (idealized) smooth fields on a smooth spacetime. In the context of applications to cosmology such `energy diffusion' from the low energy matter degrees of freedom to the discrete structures underlying spacetime leads to the emergence of an effective dark energy term in Einstein's equations. We estimate this effect using a (relational) hypothesis about the materialization of discreteness in quantum gravity which is motivated by the strict observational constraints supporting the validity of Lorentz invariance at low energies. The predictions coming from simple dimensional analysis yield a cosmological constant of the order of magnitude of the observed value without fine tuning.Comment: Typos corrected, closer to published versio

Linear systems of rational curves on rational surfaces

Given a curve C on a projective nonsingular rational surface S, over an algebraically closed field of characteristic zero, we are interested in the set Omega_C of linear systems Lambda on S satisfying C is in Lambda, dim Lambda > 0, and the general member of Lambda is a rational curve. The main result of the paper gives a complete description of Omega_C and, in particular, characterizes the curves C for which Omega_C is non empty

Nonequilibrium structures and dynamic transitions in driven vortex lattices with disorder

We review our studies of elastic lattices driven by an external force $F$ in the presence of random disorder, which correspond to the case of vortices in superconducting thin films driven by external currents. Above a critical force $F_c$ we find two dynamical phase transitions at $F_p$ and $F_t$, with $F_c<F_p<F_t$. At $F_p$ there is a transition from plastic flow to smectic flow where the noise is isotropic and there is a peak in the differential resistance. At $F_t$ there is a sharp transition to a frozen transverse solid where both the transverse noise and the diffussion fall down abruptly and therefore the vortex motion is localized in the transverse direction. From a generalized fluctuation-dissipation relation we calculate an effective transverse temperature in the fluid moving phases. We find that the effective temperature decreases with increasing driving force and becomes equal to the equilibrium melting temperature when the dynamic transverse freezing occurs.Comment: 8 pages, 3 fig

Lorentz Invariance Violation and its Role in Quantum Gravity Phenomenology

The notion that gravitation might lead to a breakdown of standard space-time structure at small distances, and that this might affect the propagation of ordinary particles has led to a program to search for violations of Lorentz invariance as a probe of quantum gravity. Initially it was expected that observable macroscopic effects caused by microscopic violations of Lorentz invariance would necessarily be suppressed by at least one power of the small ratio between the Planck length and macroscopic lengths. Here we discuss the implications of the fact that this expectation is in contradiction with standard properties of radiative corrections in quantum field theories. In normal field theories, radiative corrections in the presence of microscopic Lorentz violation give macroscopic Lorentz violation that is suppressed only by the size of Standard Model couplings, in clear conflict with observation. In general, this conclusion can only be avoided by extreme fine tuning of the parameters of the theory.Comment: Draft chapter contributed to the book "Towards quantum gravity", being prepared by Daniele Oriti for Cambridge University Pres