Robust seismic velocity change estimation using ambient noise recordings

We consider the problem of seismic velocity change estimation using ambient noise recordings. Motivated by [23] we study how the velocity change estimation is affected by seasonal fluctuations in the noise sources. More precisely, we consider a numerical model and introduce spatio-temporal seasonal fluctuations in the noise sources. We show that indeed, as pointed out in [23], the stretching method is affected by these fluctuations and produces misleading apparent velocity variations which reduce dramatically the signal to noise ratio of the method. We also show that these apparent velocity variations can be eliminated by an adequate normalization of the cross-correlation functions. Theoretically we expect our approach to work as long as the seasonal fluctuations in the noise sources are uniform, an assumption which holds for closely located seismic stations. We illustrate with numerical simulations and real measurements that the proposed normalization significantly improves the accuracy of the velocity change estimation

Giant Optical Non-linearity induced by a Single Two-Level System interacting with a Cavity in the Purcell Regime

A two-level system that is coupled to a high-finesse cavity in the Purcell regime exhibits a giant optical non-linearity due to the saturation of the two-level system at very low intensities, of the order of one photon per lifetime. We perform a detailed analysis of this effect, taking into account the most important practical imperfections. Our conclusion is that an experimental demonstration of the giant non-linearity should be feasible using semiconductor micropillar cavities containing a single quantum dot in resonance with the cavity mode.Comment: 40 pages, 16 figures, accepted in Phys. Rev.

Intramolecular vibronic dynamics in molecular solids: C60

Vibronic coupling in solid C60 has been investigated with a combination of resonant photoemission spectroscopy (RPES) and resonant inelastic x-ray scattering (RIXS). Excitation as a function of energy within the lowest unoccupied molecular orbital resonance yielded strong oscillations in intensity and dispersion in RPES, and a strong inelastic component in RIXS. Reconciling these two observations establishes that vibronic coupling in this core hole excitation leads to predominantly inelastic scattering and localization of the excited vibrations on the molecule on a femtosecond time scale. The coupling extends throughout the widths of the frontier valence bands.

Universal singularity at the closure of a gap in a random matrix theory

We consider a Hamiltonian $H = H_0+ V$, in which $H_0$ is a given non-random Hermitian matrix,and $V$ is an $N \times N$ Hermitian random matrix with a Gaussian probability distribution.We had shown before that Dyson's universality of the short-range correlations between energy levels holds at generic points of the spectrum independently of $H_{0}$. We consider here the case in which the spectrum of $H_{0}$ is such that there is a gap in the average density of eigenvalues of $H$ which is thus split into two pieces. When the spectrum of $H_{0}$ is tuned so that the gap closes, a new class of universality appears for the energy correlations in the vicinity of this singular point.Comment: 20pages, Revtex, to be published in Phys. Rev.

Helping to heal nature and ourselves through human-rights-based and gender-responsive One Health

Abstract: The health of our planet and humanity is threatened by biodiversity loss, disease and climate crises that are unprecedented in human history, driven by our insatiable consumption and unsustainable production patterns, particularly food systems. The One Health approach is a pathway to synergistically addressing outcomes in term of health and sustainability, but gender issues at the One Health and biodiversity nexus are largely ignored. By examining the roles and responsibilities of Indigenous and Local People, and especially women, in conserving natural resources, and the social costs of living at the Human-Animal-Environment interface under current conservation strategies, we show that women bear a disproportionate health, poverty and climate burden, despite having pivotal roles in conserving biodiversity. To mitigate risks of emerging infectious diseases, food insecurity and climate change impacts, a gender perspective has previously been proposed, but implementation lags behind. Endemic zoonotic diseases, human-wildlife conflict and environmental pollution lack gender-sensitive frameworks. We demonstrate that women can be powerful agents for change at all levels of society, from communities to businesses, and policy-making institutions, but gender inequalities still persist. We develop a framework for mainstreaming a gender-responsive and rights-based One Health approach, in order to heal ourselves and nature. Using a leverage-points perspective, we suggest a change of paradigm, from the pursuit of GDP and over-consumption, to a focus on human well-being and their reconnection with healthy environments, using a One Health understanding of nature and health. We recommend learning from Indigenous People to re-position ourselves within nature and to better conserve biodiversity. We also propose integration of gender equity in leadership, the respect of human rights, women’s rights (access to health care, healthy food, land tenure, natural resources, education, and economic opportunities), and the rights of nature, through the implementation of gender-responsive and rights-based One Health Action Plans, at policy-making level, in the private sector and the civil society. As the COVID-19 pandemic continues to unveil deep socio-economic inequities in the wealthiest economies and the vital role of nature in supporting our health, we argue to seize this opportunity to build back better and improve resilience and sustainability by using a gender-responsive and rights-based One Health approach

Universal integrals for superintegrable systems on N-dimensional spaces of constant curvature

An infinite family of classical superintegrable Hamiltonians defined on the N-dimensional spherical, Euclidean and hyperbolic spaces are shown to have a common set of (2N-3) functionally independent constants of the motion. Among them, two different subsets of N integrals in involution (including the Hamiltonian) can always be explicitly identified. As particular cases, we recover in a straightforward way most of the superintegrability properties of the Smorodinsky-Winternitz and generalized Kepler-Coulomb systems on spaces of constant curvature and we introduce as well new classes of (quasi-maximally) superintegrable potentials on these spaces. Results here presented are a consequence of the sl(2) Poisson coalgebra symmetry of all the Hamiltonians, together with an appropriate use of the phase spaces associated to Poincare and Beltrami coordinates.Comment: 12 page