The Isospin Asymmetry in Anomalous Fluid Dynamics

The dynamics of fluids in which the constituent particles carry nonabelian charges can be described succinctly in terms of group-valued variables via a generalization of the co-adjoint orbit action for particles. This formalism, which is particularly suitable for incorporating anomalies, has previously been used for the chiral magnetic and chiral vorticity effects. Here we consider the similar effect for the isospin which corresponds to an angular asymmetry for neutral pions.Comment: 12 page

Hygienic requirements of urban living environment in the Russian Federation and in Italy: a comparison

Introduzione/scopo. La pianificazione urbana tende a contenere e regolamentare la crescita urbana consentendo uno sviluppo sostenibile a livello ambientale, sociale e sanitario. Nel presente lavoro gli autori hanno confrontato i quadri normativi della Federazione Russ e dell’Italia ponendo particolare attenzione agli aspetti urbani degli spazi abitativi. Metodo. Considerando la ponderosa produzione normativa nei due paesi, il lavoro ha preso in esame le normative a livello nazionale per l’Italia e federale per la Russia, tenendo principalmente conto dei seguenti aspetti: strumenti di pianificazione urbana e protezione ambientale e sanitaria degli spazi abitativi. Risultati. I problemi relativi alla sicurezza igienico-sanitaria dell’ambiente di vita in Russia sono essenzialmente riconducibili a due sistemi normativi (SNiP e SanPiN), mentre in Italia rientrano nel D.M. 05/07/1975. I principi fondamentali della pianificazione urbana in Russia sono dettati da una norma federale, mentre in Italia sono recepiti nel Piano Regolatore Generale (PRG) comunale e nei diversi regolamenti locali, dove si riasriassume tutta la normativa sovraordinata. Gli aspetti legati alla qualità ambientale, infine, in entrambi i paesi sono disciplinati da varie leggi specifiche (federali e statali); un articolato sistema di norme che tengono conto dei potenziali impatti sulla salute e sull’ambiente Conclusioni. Gli autori ritengono che dovrebbero essere sviluppati, specialmente in Italia che si trova nettamente più indietro da questo punto di vista, strumenti normativi chiari e aggiornati aventi per oggetto l’igiene degli edifici e degli ambienti urbani, basati sulle più recenti acquisizioni di letteratura scientifica internazionale nell’intento di garantire i più alti standard in materia di tutela della Salute Pubblica.Aim. Urban planning tries to contain and regulate the uncontrolled growth of cities, encouraging their sustainable development at environmental, social and health levels. In the present work, the authors compare the regulatory frameworks of the Russian Federation and of Italy, with particular attention paid to the urban aspects of living spaces. Method. Considering the extant normative production in the two countries, the authors examine national legislation for Italy and federal legislation for Russia, mainly taking into account the following aspects: urban planning tools and environmental and sanitary protection of living spaces. Results. Hygienic-sanitary requirements regarding living environment in Russia are essentially expressed by two regulatory systems (SNiP and SanPiN), while in Italy they are regulated by the D.M. 07/05/1975. The main principles of urban planning in Russia are expressed by federal standards, while in Italy they are incorporated in the Municipal General Plan (PRG) and in the various local regulations, where all the superordinate regulations are summarized. Finally, aspects related to environmental quality in both countries are governed by various specific laws (federal and state); a complex system of rules that take into account potential impacts on health and the environment. Conclusions. The authors reckon that clear and updated regulatory tools should be developed, especially in Italy that lags behind, regarding the building and urban hygiene, relying on the most recent acquisitions of international scientific literature in order to guarantee the highest standards in Public Health safeguard

On the evolution of the entropy and pressure profiles in X-ray luminous galaxy clusters at z > 0.4

Galaxy clusters are the most recent products of hierarchical accretion over cosmological scales. The gas accreted from the cosmic field is thermalized inside the cluster halo. Gas entropy and pressure are expected to have a self-similar behaviour with their radial distribution following a power law and a generalized Navarro-Frenk-White profile, respectively. This has been shown also in many different hydrodynamical simulations. We derive the spatially-resolved thermodynamical properties of 47 X-ray galaxy clusters observed with Chandra in the redshift range 0.4 < z < 1.2, the largest sample investigated so far in this redshift range with X-rays spectroscopy, with a particular care in reconstructing the gas entropy and pressure radial profiles. We search for deviation from the self-similar behaviour and look for possible evolution with redshift. The entropy and pressure profiles lie very close to the baseline prediction from gravitational structure formation. We show that these profiles deviate from the baseline prediction as function of redshift, in particular at z > 0.75, where, in the central regions, we observe higher values of the entropy (by a factor of 2.2) and systematically lower estimates (by a factor of 2.5) of the pressure. The effective polytropic index, which retains informations about the thermal distribution of the gas, shows a slight linear positive evolution with the redshift and the concentration of the dark matter distribution. A prevalence of non-cool-core, disturbed systems, as we observe at higher redshifts, can explain such behaviours.Comment: 14 pages, 18 figures, accepted for publication by A&

Layered superconductors as negative-refractive-index metamaterials

We analyze the use of layered superconductors as anisotropic metamaterials. Layered superconductors can have a negative refraction index in a wide frequency range for arbitrary incident angles. Indeed, low-Tc (s-wave) superconductors allow to produce artificial heterostructures with low losses for T<<Tc. However, the real part of their in-plane effective permittivity is very large. Moreover, even at low temperatures, layered high-Tc superconductors have a large in-plane normal conductivity, producing large losses (due to d-wave symmetry). Therefore, it is difficult to enhance the evanescent modes in either low-Tc or high-Tc superconductors.Comment: 4 pages, 2 figure

Quantum-Coherence-Enhanced Surface Plasmon Amplification by Stimulated Emission of Radiation

We investigate surface plasmon amplification in a silver nanoparticle coupled to an externally driven three-level gain medium, and show that quantum coherence significantly enhances the generation of surface plasmons. Surface plasmon amplification by stimulated emission of radiation is achieved in the absence of population inversion on the spasing transition, which reduces the pump requirements. The coherent drive allows us to control the dynamics, and holds promise for quantum control of nanoplasmonic devices.Comment: 5 pages, 4 figure

Nonlinear Micromechanical Casimir Oscillator

The Casimir force between uncharged metallic surfaces originates from quantum mechanical zero point fluctuations of the electromagnetic field. We demonstrate that this quantum electrodynamical effect has a profound influence on the oscillatory behavior of microstructures when surfaces are in close proximity (<= 100 nm). Frequency shifts, hysteretic behavior and bistability caused by the Casimir force are observed in the frequency response of a periodically driven micromachined torsional oscillator.Comment: 4 pages, 4 figures; added and rearranged references; added comments on sensitivit

Nonlinear feedback oscillations in resonant tunneling through double barriers

We analyze the dynamical evolution of the resonant tunneling of an ensemble of electrons through a double barrier in the presence of the self-consistent potential created by the charge accumulation in the well. The intrinsic nonlinearity of the transmission process is shown to lead to oscillations of the stored charge and of the transmitted and reflected fluxes. The dependence on the electrostatic feedback induced by the self-consistent potential and on the energy width of the incident distribution is discussed.Comment: 10 pages, TeX, 5 Postscript figure

Precision measurement of the Casimir-Lifshitz force in a fluid

The Casimir force, which results from the confinement of the quantum mechanical zero-point fluctuations of the electromagnetic fields, has received significant attention in recent years for its effect on micro- and nano-scale mechanical systems. With few exceptions, experimental observations have been limited to conductive bodies interacting separated by vacuum or air. However, interesting phenomena including repulsive forces are expected to exist in certain circumstances between metals and dielectrics when the intervening medium is not vacuum. In order to better understand the effect of the Casimir force in such situations and to test the robustness of the generalized Casimir-Lifshitz theory, we have performed the first precision measurements of the Casimir force between two metals immersed in a fluid. For this situation, the measured force is attractive and is approximately 80% smaller than the force predicted by Casimir for ideal metals in vacuum. We present experimental results and find them to be consistent with Lifshitz's theory.Comment: 6 pages, 3 figures. (version before final publication

Horava-Lifshitz gravity: tighter constraints for the Kehagias-Sfetsos solution from new solar system data

We analytically work out the perturbation induced by the Kehagias-Sfetsos (KS) space-time solution of the Horava-Lifshitz (HL) modified gravity at long distances on the two-body range for a pair of test particles A and B orbiting the same mass M. We apply our results to the most recently obtained range-residuals \delta\rho for some planets of the solar system (Mercury, Mars, Saturn) ranged from the Earth to effectively constrain the dimensionsless KS parameter \psi_0 for the Sun. We obtain \psi_0 >= 7.2 x 10^-10 (Mercury), \psi_0 >= 9 x 10^-12 (Mars), \psi_0 >= 1.7 x 10^-12 (Saturn). Such lower bounds are tighter than other ones existing in literature by several orders of magnitude. We also preliminarily obtain \psi_0 >= 8 x 10^-10 for the system constituted by the S2 star orbiting the Supermassive Black Hole (SBH) in the center of the Galaxy.Comment: LaTex2e, 15 pages, 1 table, 3 figures, 31 references. Version matching the one at press in International Journal of Modern Physics D (IJMPD