Bogoliubov excitations driven by thermal lattice phonons in a quantum fluid of light

Elementary excitations in weakly interacting quantum fluids have a correlated particle-hole nature that leads to spectacular macroscopic quantum phenomena such as superfluidity. This many-body character was established in the context of cold-atom condensates at thermal equilibrium in the framework of Bogoliubov's celebrated theory of the weakly interacting Bose gas. Bogoliubov excitations were also found to be highly relevant to driven-dissipative quantum fluid of light, with certain resulting phenomena strikingly analogue to their equilibrium counterparts, but also genuine out-of-equilibrium aspects. In this work, we investigate both theoretically and experimentally a regime in which the elementary excitations in a quantum fluid of light result dominantly from their interaction with thermal lattice phonons, namely the elementary vibrations of the crystal. By an accurate comparison with the theoretically predicted spectral function of the driven-dissipative quantum fluid we achieve a quantitative understanding of the particle-hole nature of the elementary excitations, and unveil a remarkable decoupling from thermal excitations which is expected to be relevant in equilibrium quantum fluids as well. Finally, we exploit this quantitative understanding to identify a crossover temperature around $1\,$K, below which the lattice phonons are sufficiently quieted down for the quantum fluctuations to take over in the generation of Bogoliubov excitations. This regime is highly desired as it is characterized by strong quantum correlations between Bogoliubov excitations.Comment: Main text: 22 pages 6 figures, Supplementary Information : 4 pages, 3 figure

Multicentric survey on dose reduction/interruption of cancer drug therapy in 12.472 patients: Indicators of suspected adverse reactions

Antiblastic drugs have a high number of potential side-effects. Paradoxically, according to the National Network of Pharmacovigilance, the number of reported adverse reactions to these agents is proportionally lower than that registered for non antiblastic drugs. Critical phenomena such as treatment interruptions and significant dose reductions within the first two months of use may be indicators of adverse drug reactions. The aim of the present study was to increase our knowledge of pharmacovigilance to facilitate the actions taken to improve the risk-benefit profile of cancer drugs and, consequently, their safety. This retrospective observational survey was carried out on prescriptions from 1st January 2012 to 31st December 2012.Dose reductions of more than 10% during the first 90 days of therapy were considered as a surrogate indicator of an adverse reaction. Dose interruptions during the first 60 days of therapy were taken into consideration. Of the12,472 patients 1,248 underwent a dose reduction. The drugs that most often required a dose reduction were paclitaxel and oxaliplatin (17.4% and 17.3%, respectively), docetaxel (14.8%), carboplatin (15%), fluorouracil (10.7%) and, among oral medications, capecitabine (6.9%). Of the 1896 patients treated with the same drugs, 9.7% interrupted treatment. Patients required a lower dose reduction than that reported by other authors. Around 15% of cases underwent a 30% dose reduction within three months of starting therapy, indicating a possible adverse reaction. Constant monitoring of dose prescription and continuous training of medical and nursing staff are clearly needed to increase awareness of the importance of reporting adverse events.Antiblastic drugs have a high number of potential side-effects. Paradoxically, according to the National Network of Pharmacovigilance, the number of reported adverse reactions to these agents is proportionally lower than that registered for non antiblastic drugs. Critical phenomena such as treatment interruptions and significant dose reductions within the first two months of use may be indicators of adverse drug reactions. The aim of the present study was to increase our knowledge of pharmacovigilance to facilitate the actions taken to improve the risk-benefit profile of cancer drugs and, consequently, their safety. This retrospective observational survey was carried out on prescriptions from 1st January 2012 to 31st December 2012. Dose reductions of more than 10% during the first 90 days of therapy were considered as a surrogate indicator of an adverse reaction. Dose interruptions during the first 60 days of therapy were taken into consideration. Of the12,472 patients 1,248 underwent a dose reduction. The drugs that most often required a dose reduction were paclitaxel and oxaliplatin (17.4% and 17.3%, respectively), docetaxel (14.8%), carboplatin (15%), fluorouracil (10.7%) and, among oral medications, capecitabine (6.9%). Of the 1896 patients treated with the same drugs, 9.7% interrupted treatment. Patients required a lower dose reduction than that reported by other authors. Around 15% of cases underwent a 30% dose reduction within three months of starting therapy, indicating a possible adverse reaction. Constant monitoring of dose prescription and continuous training of medical and nursing staff are clearly needed to increase awareness of the importance of reporting adverse events

The Italian open data meteorological portal: MISTRAL

AbstractAt the national level, in Italy, observational and forecast data are collected by various public bodies and are often kept in various small, heterogeneous and non‐interoperable repositories, released under different licenses, thus limiting the usability for external users. In this context, MISTRAL (the Meteo Italian SupercompuTing PoRtAL) was launched as the first Italian meteorological open data portal, with the aim of promoting the reuse of meteorological data sets available at national level coverage. The MISTRAL portal provides (and archives) meteorological data from various observation networks, both public and private, and forecast data that are generated and post‐processed within the Consortium for Small‐scale Modeling‐Limited Area Model Italia (COSMO‐LAMI) agreement using high performance computing (HPC) facilities. Also incorporated is the Italy Flash Flood use case, implemented with the collaboration of European Centre for Medium‐Range Weather Forecasts (ECMWF), which exploits cutting edge advances in HPC‐based post‐processing of ensemble precipitation forecasts, for different model resolutions, and applies those to deliver novel blended‐resolution forecasts specifically for Italy. Finally, in addition to providing architectures for the acquisition and display of observational data, MISTRAL also delivers an interactive system for visualizing forecast data of different resolutions as superimposed multi‐layer maps

Bogoliubov Excitations Driven by Thermal Lattice Phonons in a Quantum Fluid of Light

The elementary excitations in weakly interacting quantum fluids have a nontrivial nature which is at the basis of defining quantum phenomena such as superfluidity. These excitations and the physics they lead to have been explored in closed quantum systems at thermal equilibrium both theoretically within the celebrated Bogoliubov framework and experimentally in quantum fluids of ultracold atoms. Over the past decade, the relevance of Bogoliubov excitations has become essential to understand quantum fluids of interacting photons. Their driven-dissipative character leads to distinct properties with respect to their equilibrium counterparts. For instance, the condensate coupling to the photonic vacuum environment leads to a nonzero generation rate of elementary excitations with many striking implications. In this work, considering that quantum fluids of light are often hosted in solid-state systems, we show within a joint theory-experiment analysis that the vibrations of the crystal constitute another environment that the condensate is fundamentally coupled to. This coupling leads to a unique heat transfer mechanism, resulting in a large generation rate of elementary excitations in typical experimental conditions, and to a fundamental nonzero contribution at vanishing temperatures. Our work provides a complete framework for solid-embedded quantum fluids of light, which is invaluable in view of achieving a regime dominated by photon-vacuum fluctuations

Bogoliubov Excitations Driven by Thermal Lattice Phonons in a Quantum Fluid of Light

The elementary excitations in weakly interacting quantum fluids have a nontrivial nature which is at the basis of defining quantum phenomena such as superfluidity. These excitations and the physics they lead to have been explored in closed quantum systems at thermal equilibrium both theoretically within the celebrated Bogoliubov framework and experimentally in quantum fluids of ultracold atoms. Over the past decade, the relevance of Bogoliubov excitations has become essential to understand quantum fluids of interacting photons. Their driven-dissipative character leads to distinct properties with respect to their equilibrium counterparts. For instance, the condensate coupling to the photonic vacuum environment leads to a nonzero generation rate of elementary excitations with many striking implications. In this work, considering that quantum fluids of light are often hosted in solid-state systems, we show within a joint theory-experiment analysis that the vibrations of the crystal constitute another environment that the condensate is fundamentally coupled to. This coupling leads to a unique heat transfer mechanism, resulting in a large generation rate of elementary excitations in typical experimental conditions, and to a fundamental nonzero contribution at vanishing temperatures. Our work provides a complete framework for solid-embedded quantum fluids of light, which is invaluable in view of achieving a regime dominated by photon-vacuum fluctuations.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

An efficient CuxOCu_xO photocathode for hydrogen production at neutral pH : new insights from combined spectroscopy and electrochemistry

Light-driven water splitting is one of the most promising approaches for using solar energy in light of more sustainable development. In this paper, a highly efficient p-type copper(II) oxide photocathode is studied. The material, prepared by thermal treatment of CuI nanoparticles, is initially partially reduced upon working conditions and soon reaches a stable form. Upon visible-light illumination, the material yields a photocurrent of 1.3 mA cm-2 at a potential of 0.2 V vs a reversible hydrogen electrode at mild pH under illumination by AM 1.5 G and retains 30% of its photoactivity after 6 h. This represents an unprecedented result for a nonprotected Cu oxide photocathode at neutral pH. The photocurrent efficiency as a function of the applied potential was determined using scanning electrochemical microscopy. The material was characterized in terms of photoelectrochemical features; X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, fixed-energy X-ray absorption voltammetry, and extended X-ray absorption fine structure analyses were carried out on pristine and used samples, which were used to explain the photoelectrochemical behavior. The optical features of the oxide are evidenced by direct reflectance spectroscopy and fluorescence spectroscopy, and Mott-Schottky analysis at different pH values explains the exceptional activity at neutral pH