Collective Molecular Dynamics of a Floating Water Bridge

When a high voltage is applied to pure water filling two beakers kept close to each other, a connection forms spontaneously, giving the impression of a floating water bridge. This phenomenon is of special interest, since it comprises a number of phenomena currently tackled in modern water science. The formation and the main properties of this floating water bridge are analyzed in the conceptual framework of quantum electrodynamics. The necessary conditions for the formation are investigated as well as the time evolution of the dynamics. The predictions are found in agreement with the observations.Comment: 11 pages, 4 figure

Analysis of the contributions of three-body potentials in the equation of state of 4He

The effect of three-body interatomic contributions in the equation of state of 4He are investigated. A recent two-body potential together with the Cohen and Murrell (Chem. Phys. Lett. 260, 371 (1996)) three-body potential are applied to describe bulk helium. The triple-dipole dispersion and exchange energies are evaluated subjected only to statistical uncertainties. An extension of the diffusion Monte Carlo method is applied in order to compute very small energies differences. The results show how the three-body contributions affects the ground-state energy, the equilibrium, melting and freezing densities.Comment: 18 pages, 3 figures, 4 table

Flavor states of mixed neutrinos

By resorting to previous results on flavor mixing in Quantum Field Theory, we show how to consistently define flavor states of mixed neutrinos as eigenstates of the flavor charge operators.Comment: 4 pages, presented at 13th International Symposium on Particles, Strings and Cosmology, PASCOS-07, 2-7 July 2007, Imperial College Londo

Migrants, Communities, and Culture

New immigrants have already changed Philadelphia\u27s cultural scene—particularly in urban neighborhoods. This brief uses three types of evidence— a small-area database of cultural participation, a survey of residents of North Philadelphia and Camden, NJ, and a survey of artists living or working in the metropolitan area—to explore migrant cultural engagement. Taken together, SIAP’s evidence on artists and cultural participants paints a portrait of migrants and foreign-born residents who are positively oriented toward cultural expression but frustrated by institutional, spatial, and socio-economic barriers. Can culture serve as a means of linking new Philadelphians to other social institutions

On flavor conservation in weak interaction decays involving mixed neutrinos

In the context of quantum field theory (QFT), we compute the amplitudes of weak interaction processes such as $W^{+} \rightarrow e^{+} + \nu_{e}$ and $W^{+} \rightarrow e^{+} + \nu_{\mu}$ by using different representations of flavor states for mixed neutrinos. Analyzing the short time limit of the above amplitudes, we find that the neutrino states defined in QFT as eigenstates of the flavor charges lead to results consistent with lepton charge conservation. On the contrary, the Pontecorvo flavor states produce a violation of lepton charge in the vertex, which is in contrast with what expected at tree level in the Standard Model.Comment: 15 page

Privileged burial in the Pava Pieve (Siena, 8th century AD)

During the 6th archaeological excavation campaign performed at the «Pieve di Pava» (San Giovanni d’Asso, Siena, Italy) in the summer of 2009, a stone-lined burial of a high-status single individual (US 2378) was discovered, covered by a monolithic slab and placed in front of the altar. The tomb is about 160 cm long, 40 cm wide and over 70 cm deep. The skeletal remains of a young male (18-20 years), not in anatomical connection, were found on the floor of the tomb. 14C dating revealed a period between 650 and 688 AD. Stable isotope analysis (18O, 13C, 15N) attested that he was a member of the local community, with a diet quite rich in animal proteins. We are in presence of the secondary burial of an eminent personage, perhaps a saint, likely to have been transported to the church in a sack of perishable material, possibly textile, which caused their alignment along a curved line, as clearly demonstrated by the circular delimitation of the bones. The body was probably used for the re-consecration of the church, following the restoration works of the 8th century. The paleopathological study diagnosed a case of acromesomelic dysplasia, a congenital anomaly with disproportionate limbs: short, enlarged distal segments (radius-ulna and tibia), almost normal proximal segments (humerus and femur), short stature of about 150 cm, and bilateral fibular agenesis. Tibiae malformation and fibulae agenesis led to bilateral talipes valgus, with major walking problems. Extensive enthesopathies in the upper limbs indicate the use of crutches

Phase-sensitive terahertz imaging using room-temperature near-field nanodetectors

Imaging applications in the terahertz (THz) frequency range are severely restricted by diffraction. Near-field scanning probe microscopy is commonly employed to enable mapping of the THz electromagnetic fields with sub-wavelength spatial resolution, allowing intriguing scientific phenomena to be explored, such as charge carrier dynamics in nanostructures and THz plasmon-polaritons in novel 2D materials and devices. High-resolution THz imaging, so far, has relied predominantly on THz detection techniques that require either an ultrafast laser or a cryogenically cooled THz detector. Here, we demonstrate coherent near-field imaging in the THz frequency range using a room-temperature nanodetector embedded in the aperture of a near-field probe, and an interferometric optical setup driven by a THz quantum cascade laser. By performing phase-sensitive imaging of strongly confined THz fields created by plasmonic focusing, we demonstrate the potential of our novel architecture for high-sensitivity coherent THz imaging with sub-wavelength spatial resolution. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

High performance bilayer-graphene Terahertz detectors

We report bilayer-graphene field effect transistors operating as THz broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity $\sim 1.2V/W (1.3 mA/W)$ and a noise equivalent power $\sim 2\times 10^{-9} W/Hz^{-1/2}$ in the 0.29-0.38 THz range, in photovoltage and photocurrent mode. The potential of this technology for scalability to higher frequencies and the development of flexible devices makes our approach competitive for a future generation of THz detection systems.Comment: 8 pages, 5 figures. Submitted to Applied Physics Letter

Quantum noise induced entanglement and chaos in the dissipative quantum model of brain

We discuss some features of the dissipative quantum model of brain in the frame of the formalism of quantum dissipation. Such a formalism is based on the doubling of the system degrees of freedom. We show that the doubled modes account for the quantum noise in the fluctuating random force in the system-environment coupling. Remarkably, such a noise manifests itself through the coherent structure of the system ground state. The entanglement of the system modes with the doubled modes is shown to be permanent in the infinite volume limit. In such a limit the trajectories in the memory space are classical chaotic trajectories.Comment: 14 page