Singular potentials: Confinement and Riemann hypothesis

We analyze the role of singular potentials in quantum mechanics and field theory. In particular, we focus on the conformal invariant potential V (x) = 1/x2 which governs interesting physical phenomena like Efimov effect in atomic and nuclear compounds, quark confinement in QCD, scaling dimensions in the AdS/CFT correspondence, impurity effects in graphene and even models of the P´olya-Hilbert approach to the Riemann hypothesis

Interferometric length metrology for the dimensional control of ultra-stable Ring Laser Gyroscopes

We present the experimental test of a method for controlling the absolute length of the diagonals of square ring laser gyroscopes. The purpose is to actively stabilize the ring cavity geometry and to enhance the rotation sensor stability in order to reach the requirements for the detection of the relativistic Lense-Thirring effect with a ground-based array of optical gyroscopes. The test apparatus consists of two optical cavities 1.32 m in length, reproducing the features of the ring cavity diagonal resonators of large frame He-Ne ring laser gyroscopes. The proposed measurement technique is based on the use of a single diode laser, injection locked to a frequency stabilized He-Ne/Iodine frequency standard, and a single electro-optic modulator. The laser is modulated with a combination of three frequencies allowing to lock the two cavities to the same resonance frequency and, at the same time, to determine the cavity Free Spectral Range (FSR). We obtain a stable lock of the two cavities to the same optical frequency reference, providing a length stabilization at the level of 1 part in $10^{11}$, and the determination of the two FSRs with a relative precision of 0.2 ppm. This is equivalent to an error of 500 nm on the absolute length difference between the two cavities

Modification of electronic surface states by graphene islands on Cu(111)

We present a study of graphene/substrate interactions on UHV-grown graphene islands with minimal surface contamination using \emph{in situ} low-temperature scanning tunneling microscopy (STM). We compare the physical and electronic structure of the sample surface with atomic spatial resolution on graphene islands versus regions of bare Cu(111) substrate. We find that the Rydberg-like series of image potential states is shifted toward lower energy over the graphene islands relative to Cu(111), indicating a decrease in the local work function, and the resonances have a much smaller linewidth, indicating reduced coupling to the bulk. In addition, we show the dispersion of the occupied Cu(111) Shockley surface state is influenced by the graphene layer, and both the band edge and effective mass are shifted relative to bare Cu(111).Comment: 12 pages, 3 figure

De los grupos espontáneos a las comunidades de base. Fe y política en la contestación postconciliar italiana (1965-1969)

El principal objetivo de este artículo es investigar la relación entre la dimensión religiosa y la política de la recepción en Italia del Concilio Vaticano II desde el final de la reunión conciliar hasta la eclosión de Mayo del 68. De un modo más específico, esta contribución aborda el desarrollo de las protestas del mundo católico contra la jerarquía y contra el sistema político, e igualmente, el desarrollo de los grupos espontáneos y su evolución en las comunidades de base.The main goal of the paper is to investigate the relationship between the religious and political dimension in the Italian reception of Vatican II from the end of the Council to the explosion of May 1968. More specifically, the paper deals with the development of the Catholic protest against the Hierarchy and the political system, the development of spontaneous groups and their evolution into the Ecclesial Base Communities

Pulmonary adenocarcinoma mutation profile in smokers with smoking-related interstitial fibrosis

Cigarette smoking is an established cause of lung cancer. However, pulmonary fibrosis is also an independent risk factor for the development of lung cancer. Smoking-related interstitial fibrosis (SRIF) has recently been reported. We hypothesized that adenocarcinomas in lungs with SRIF might show distinct molecular changes and examined the molecular phenotype of 168 resected lung adenocarcinomas in lungs with and without SRIF. The diagnosis of SRIF was determined by histological examination, based on the presence of alveolar septal thickening, due to pauci-inflamed, hyalinized, “ropy” collagen, in areas of lung greater than 1 cm away from the tumor. Tumors were concomitantly examined genotypically for mutations in genes frequently altered in cancer, including EGFR and KRAS, by SNaPshot and by fluorescence in situ hybridization for possible ALK rearrangements. Fluorescence in situ hybridization for ROS1 rearrangement (n=36) and/or MET amplification (n=31) were performed when no mutation was identified by either SNaPshot or ALK analysis. Sixty-five cases (38.7%) showed SRIF, which was distributed in all lobes of the lungs examined. No differences were observed in sex, average age, or smoking history in patients with and without SRIF. There was no difference in either the percent or types of adenocarcinoma genetic mutations in patients with SRIF versus those without. This data suggests that SRIF does not represent an independent risk factor for the development of the major known and targeted mutations seen in pulmonary adenocarcinoma. However, additional research is required to investigate the potential significance of SRIF in the pathogenesis of lung cancer

Geometrical scale-factor stabilization of square cavity ring laser gyroscopes

Large frame ring laser gyros performances are ultimately limited by the instabilities of their geometrical parameters. We present the experimental activity on the GP2 ring laser gyro. GP2 is a ring laser gyro devoted to develop advanced stabilization techniques of the ring cavity geometrical scale-factor. A method based on optical interferometry has been developed for canceling the deformations of the resonator. The method is based on the measurement and stabilization of the absolute length of the cavity perimeter and of the resonators formed by the opposite cavity mirrors. The optical frequency reference in the experiment is an iodine-stabilized He-Ne laser, with a relative frequency stability of 10-11. The measurement of the absolute length of the two resonators has been demonstrated up to now on a test bench. We discuss the experimental results on GP2: the present performances as a ring laser gyro and the stabilization scheme to be implemented in the near future

Optimization of the geometrical stability in square ring laser gyroscopes

Ultra sensitive ring laser gyroscopes are regarded as potential detectors ofthe general relativistic frame-dragging effect due to the rotation of theEarth: the project name is GINGER (Gyroscopes IN GEneral Relativity), aground-based triaxial array of ring lasers aiming at measuring the Earthrotation rate with an accuracy of 10^-14 rad/s. Such ambitious goal is nowwithin reach as large area ring lasers are very close to the necessarysensitivity and stability. However, demanding constraints on the geometricalstability of the laser optical path inside the ring cavity are required. Thuswe have started a detailed study of the geometry of an optical cavity, in orderto find a control strategy for its geometry which could meet the specificationsof the GINGER project. As the cavity perimeter has a stationary point for thesquare configuration, we identify a set of transformations on the mirrorpositions which allows us to adjust the laser beam steering to the shape of asquare. We show that the geometrical stability of a square cavity stronglyincreases by implementing a suitable system to measure the mirror distances,and that the geometry stabilization can be achieved by measuring the absolutelengths of the two diagonals and the perimeter of the ring