Quantum Astronomy at the University and INAF Astronomical Observatory of Padova, Italy

Twenty years ago, we started to apply quantum optics to the astronomical research carried out inside the Department of Physics and Astronomy and the INAF Astronomical Observatory in Padova, Italy. The initial activities were stimulated by the project of the European Southern Observatory (ESO) to build a 100 m diameter telescope, the Overwhelmingly Large (OWL) telescope. The enormous photon flux expected from such an aperture suggested that quantum optics concepts be utilized in order to obtain novel astrophysical results. Following initial successful attempts to utilize the orbital angular momentum of the light beam to enhance the visibility of faint companions to bright stars, the Padova team concentrated its efforts on very high time resolution, in order to measure and store the arrival time of celestial photons to better than one nanosecond. To obtain observational results, we built two photon counting photometers (AquEye and IquEye) to be used with our telescopes of the Asiago Observatory and with 4 m class telescopes such as the ESO New Technology Telescope (NTT) in Chile. This paper firstly describes these two instruments and then expounds the results obtained on pulsar light curves, lunar occultations and the first photon counting intensity interferometry measurements of the bright star Vega. Indeed, the correlation of photon arrival times on two or more apertures can lead to extremely high angular resolutions, as shown around 1970 by Hanbury Brown and Twiss. Prospects for quantum intensity interferometry with arrays of Cherenkov light telescopes will also be described

Adaptive real time selection for quantum key distribution in lossy and turbulent free-space channels

The unconditional security in the creation of cryptographic keys obtained by quantum key distribution (QKD) protocols will induce a quantum leap in free-space communication privacy in the same way that we are beginning to realize secure optical fiber connections. However, free-space channels, in particular those with long links and the presence of atmospheric turbulence, are affected by losses, fluctuating transmissivity, and background light that impair the conditions for secure QKD. Here we introduce a method to contrast the atmospheric turbulence in QKD experiments. Our adaptive real time selection (ARTS) technique at the receiver is based on the selection of the intervals with higher channel transmissivity. We demonstrate, using data from the Canary Island 143-km free-space link, that conditions with unacceptable average quantum bit error rate which would prevent the generation of a secure key can be used once parsed according to the instantaneous scintillation using the ARTS technique

Precise optical timing of PSR J1023+0038, the first millisecond pulsar detected with Aqueye+ in Asiago

We report the first detection of an optical millisecond pulsar with the fast photon counter Aqueye+ in Asiago. This is an independent confirmation of the detection of millisecond pulsations from PSR J1023+0038 obtained with SiFAP at the Telescopio Nazionale Galileo. We observed the transitional millisecond pulsar PSR J1023+0038 with Aqueye+ mounted at the Copernicus telescope in January 2018. Highly significant pulsations were detected. The rotational period is in agreement with the value extrapolated from the X-ray ephemeris, while the time of passage at the ascending node is shifted by $11.55 \pm 0.08$ s from the value predicted using the orbital period from the X-rays. An independent optical timing solution is derived over a baseline of a few days, that has an accuracy of $\sim 0.007$ in pulse phase ($\sim 12$ $\mu$s in time). This level of precision is needed to derive an accurate coherent timing solution for the pulsar and to search for possible phase shifts between the optical and X-ray pulses using future simultaneous X-ray and optical observations.Comment: 6 pages, 4 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society Letter

New Interpretation of Galileo\u2019s Arthritis and Blindness

Galileo Galilei (1564-1642) complained of several disorders during his life, the most important of which were chronic arthritic pains and bilateral blindness. These symptoms might result from an immune rheumatic disease, namely reactive arthritis (urethritis, uveitis, arthritis), when Galileo started suffering with an episode of fever in June 1593. Padua University owns the fifth lumbar vertebra of the great scientist and we performed a series of anthropological and radiographic analyses on it. The anthropological measurements showed that the shape of the vertebra was normal as to exclude significant diseases. The study through radiography and Computed Tomography showed only a mild arthrosis documented by small osteophytosis. Eventually the disease evolved into blindness with a pannus restricting the pupils (uveitis). These findings support the occurrence of reactive arthritis. Alternatively to urethral infection, Galileo could have suffered from Chlamydia pneumoniae infection in 1593, which was complicated by reactive arthritis a couple of weeks later. Thereafter he complained several episodes of recurrent arthritis, which eventually culminated into uveitis and bilateral blindness

Design of mechatronic systems through aspect and object-oriented modeling

Design of mechatronic systems involves the use of multiple disciplines, from mechanics to electronics and computer science. Different granularities of hybrid co-simulations with increasing details can be used during the design process. However, there is the need of modeling tools for effectively managing the necessary abstraction layers. This work proposes a combination of Aspect-Oriented and Object-Oriented modeling for reaching the goal. Moreover, it shows how the utilization of these tools can facilitate design-space exploration, segregation of domains of expertise and enhances co-design