Ambient betatron motion and its excitation by ghost lines in Tevatron

Transverse betatron motion of the Tevatron proton beam is measured and analyzed. It is shown that the motion is coherent and excited by external sources of unknown origins. Observations of the time varying ghost lines in the betatron spectra are reported.Comment: 9 p

Who comes first. rescheduling endoscopic activity after the acute phase of the Covid 19 pandemic

The current health emergency caused by the COVID19 pandemic has caused an abrupt reduction in all ordinary endoscopic activities [1]. Our endoscopy unit, usually overloaded with procedures, has reduced its activities to immediate urgencies only, as recommended by position statements of many scientific societies [2–4]. After the most critical phase of the emergency, the need to evaluate the relative urgency of the endoscopic procedures was addressed. In our endoscopic academic tertiary referral unit, about 300 endoscopic procedures from March 16 to May 2 were suspended. According to local (hospital) and regional health department indications, outpatient services have been reorganised, by remodulating time slots for procedures, controlling and filtering patients’ access to the unit and reviewing the indications for each single endoscopic procedure programmed but not performed. Procedures initially classified as urgent (by 48 hours, n. 77) and short (by 10 days, n. 68) were directly rescheduled and performed. Furthermore, we decided to interview all the patients of postponed endoscopic procedures by phone calls carried out by trainees, tutored by a senior component of the endoscopy unit. A systematic questionnaire was developed based on the following items: demographic and clinical patient characteristics, current conditions, gastrointestinal signs and symptoms, exam indications and priority classes assigned by the general practitioner or other physicians, time and results of previous endoscopic examinations, laboratory tests, ongoing treatments. Results of the phone interview and any additional clinical documentation e-mailed by the patient was evaluated and archived including date and time of the interview with the patient’s informed consent. Based on the results of the reassessment, patients were rescheduled stratifing the procedures in the following 4 priority cl

Formation of molecular hydrogen on analogues of interstellar dust grains: experiments and modelling

Molecular hydrogen has an important role in the early stages of star formation as well as in the production of many other molecules that have been detected in the interstellar medium. In this review we show that it is now possible to study the formation of molecular hydrogen in simulated astrophysical environments. Since the formation of molecular hydrogen is believed to take place on dust grains, we show that surface science techniques such as thermal desorption and time-of-flight can be used to measure the recombination efficiency, the kinetics of reaction and the dynamics of desorption. The analysis of the experimental results using rate equations gives useful insight on the mechanisms of reaction and yields values of parameters that are used in theoretical models of interstellar cloud chemistry.Comment: 23 pages, 7 figs. Published in the J. Phys.: Conf. Se

Quantum Poincar\'e Recurrences

We show that quantum effects modify the decay rate of Poincar\'e recurrences P(t) in classical chaotic systems with hierarchical structure of phase space. The exponent p of the algebraic decay P(t) ~ 1/t^p is shown to have the universal value p=1 due to tunneling and localization effects. Experimental evidence of such decay should be observable in mesoscopic systems and cold atoms.Comment: revtex, 4 pages, 4 figure

ICTs for Accessing, Understanding and Safeguarding Cultural Heritage: The Experience of INCEPTION and ROCK H2020 Projects

Today digital technologies offer great opportunities in the field of Cultural Heritage (CH). After a general overview of the European policy documents on CH digitisation, the paper aims to reflect on tools, procedures and methodologies in the use of Information and Communication Technologies (ICTs) as a new way of visualization, application and data collection towards accessing, understanding and safeguarding our historic built environment. The focus will be on two ongoing H2020 projects, INCEPTION and ROCK, selected to address the problem of CH digitisation and the access to the corresponding digitized resources in relation to historic buildings and urban districts. Therefore, they are presented as inspiring good practices for tackling this issue considering its impacts both at the architectural and urban scale. Stressing the potentials of enabling technologies, such as 3D laser surveys, environment and climate sensors, large crowd monitoring tools and CH analytic, they are also able to orient future research beyond 2020

Theoretical framework for quantum networks

We present a framework to treat quantum networks and all possible transformations thereof, including as special cases all possible manipulations of quantum states, measurements, and channels, such as, e.g., cloning, discrimination, estimation, and tomography. Our framework is based on the concepts of quantum comb-which describes all transformations achievable by a given quantum network-and link product-the operation of connecting two quantum networks. Quantum networks are treated both from a constructive point of view-based on connections of elementary circuits-and from an axiomatic one-based on a hierarchy of admissible quantum maps. In the axiomatic context a fundamental property is shown, which we call universality of quantum memory channels: any admissible transformation of quantum networks can be realized by a suitable sequence of memory channels. The open problem whether this property fails for some nonquantum theory, e.g., for no-signaling boxes, is posed.Comment: 23 pages, revtex

Macrospin dynamics in antiferromagnets triggered by sub-20 femtosecond injection of nanomagnons

The understanding of how the sub-nanoscale exchange interaction evolves in macroscale correlations and ordered phases of matter, such as magnetism and superconductivity, requires to bridging the quantum and classical worlds. This monumental challenge has so far only been achieved for systems close to their thermodynamical equilibrium. Here we follow in real time the ultrafast dynamics of the macroscale magnetic order parameter in the Heisenberg antiferromagnet KNiF 3 triggered by the impulsive optical generation of spin excitations with the shortest possible nanometre wavelength and femtosecond period. Our magneto-optical pump-probe experiments also demonstrate the coherent manipulation of the phase and amplitude of these femtosecond nanomagnons, whose frequencies are defined by the exchange energy. These findings open up opportunities for fundamental research on the role of short-wavelength spin excitations in magnetism and strongly correlated materials; they also suggest that nanospintronics and nanomagnonics can employ coherently controllable spin waves with frequencies in the 20 THz domain

Taming open/closed string duality with a Losev trick

A target space string field theory formulation for open and closed B-model is provided by giving a Batalin-Vilkovisky quantization of the holomorphic Chern-Simons theory with off-shell gravity background. The target space expression for the coefficients of the holomorphic anomaly equation for open strings are obtained. Furthermore, open/closed string duality is proved from a judicious integration over the open string fields. In particular, by restriction to the case of independence on continuous open moduli, the shift formulas of [7] are reproduced and shown therefore to encode the data of a closed string dual.Comment: 22 pages, no figures; v.2 Refs. and a comment added

Decoupling A and B model in open string theory -- Topological adventures in the world of tadpoles

In this paper we analyze the problem of tadpole cancellation in open topological strings. We prove that the inclusion of unorientable worldsheet diagrams guarantees a consistent decoupling of A and B model for open superstring amplitudes at all genera. This is proven by direct microscopic computation in Super Conformal Field Theory. For the B-model we explicitly calculate one loop amplitudes in terms of analytic Ray-Singer torsions of appropriate vector bundles and obtain that the decoupling corresponds to the cancellation of D-brane and orientifold charges. Local tadpole cancellation on the worldsheet then guarantees the decoupling at all loops. The holomorphic anomaly equations for open topological strings at one loop are also obtained and compared with the results of the Quillen formula

Modulation of LISA free-fall orbits due to the Earth-Moon system

We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr^-1 and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month (9.92 10^-7 Hz). We then evaluate the effects of these perturbations (up to the 6th harmonics) on the relative motions between each test masses couple, finding that they range between 3mm and 10pm for the 2nd and 6th harmonic, respectively. If we take the LISA sensitivity curve, as extrapolated down to 10^-6 Hz, we obtain that a few harmonics of the EM system can be detected in the Doppler data collected by the LISA space mission. This suggests that the EM system gravitational near field could provide an absolute calibration for the LISA sensitivity at very low frequencies.Comment: 15 pages, 5 figure