Welcome

• Umberto Dosselli (PD)

Room: Aula Bruno Touschek

"Celebrating 50 years of Satellite and Lunar Laser Ranging" S. Dell'Agnello (LNF) for G. Bianco (ASI)

• Simone Dell'Agnello (LNF)

Room: Aula Bruno Touschek

Quantum Communications in space using satellites

• G. Vallone (INFN Padova)

Room: Aula Bruno Touschek Quantum Communications (QC) on planetary scale require complementary channels including ground and satellite links. Here we report QC, e.g. the faithful transmission of qubits, from Space to ground by exploiting satellite corner cube retroreflectors acting as transmitter in orbit. Qubit pulses are sent at 100 MHz repetition rate and are reflected back at the single photon level from the satellite, thus mimicking a QKD source on Space. Synchronization is performed by using the bright SLR pulses at repetition rate of 10 Hz allowing for sub-nanosecond qubit arrival identification, with a factor of ten improvement with respect to the technique based on orbital parameters exploited in the first demonstration of the single photon exchange with satellites. From the link budget, the mean photon number of the state leaving the satellite has been estimated to be of the order of unity. We demonstrate the achievement of QBER of 3.7% (from LARETS satellite) and 6,7 % (from STARLETTE satellite), suitable for QKD applications. On the base of these findings, we envisage a two-way QKD protocol exploiting modulated retroreflectors that necessitates a minimal payload on satellite thus facilitating the expansion of Space QC and Quantum Physics tests in Space. Indeed, quantum communication in space give the opportunity of testing quantum physics in new environment and probing the laws of nature at large distance, beyond the capabilities of purely earth-based laboratories. The generation and distribution of entanglement, the “characteristic trait of quantum mechanics”, between two distant locations is crucial from the point of view of fundamental physics and for Quantum Information protocols. In a long term vision, experiments on quantum entanglement and quantum superposition in space are the starting point for fundamental tests on the relation between quantum phenomena and gravitation. On this base we also review possible tests of Quantum Physics in space.

Integrated Quantum Optics for Space

• Paolo Mataloni (Sapienza Università di Roma - Dipartimento di Fisica)

Room: Aula Bruno Touschek

Laser excitation of positronium to ryberg levels in high magnetic fields to produce a cold beam of antihydrogen in the AEgIS experiment

• Ruggero Caravita (INFN Genova)

Room: Aula Bruno Touschek Efficient Rydberg positronium production in high magnetic field (1T) is one of the key objectives of the AEGIS experiment at CERN (AD-6), aimed at the first direct measurement of Earth gravitational constant on a neutral antimatter system. AEGIS experimental scheme uses a charge exchange reaction between Rydberg Ps and trapped cold antiprotons to produce cold antihydrogen, subsequently accelerated via electric fields to form a free-falling beam towards a Moirè deflectometer. Thermalized positronium is first generated in a high magnetic field environment in a nanoporous silica target and later laser-excited to Rydberg levels with a two step scheme: first, from the ground state to the third excited state and subsequently to a selectable Rydberg level within the range n=16-23. In this talk, we will present the topic of exciting positronium in AEGIS conditions together with the results obtained from the current laser setup in view of the upcoming measurements

Precision measurement of the fundamental gravitational constant G with laser-cooled atomic fountains

• Guglielmo Maria Tino (FI)

Room: Aula Bruno Touschek

Observing the two-photon Breit-Wheeler process for the first time

• O. Pike (Imperial College)

Room: Aula Bruno Touschek The Breit-Wheeler process—the formation of an electron-positron pair in the collision of two photons—is the simplest way in which matter can be made from light. As the inverse process of two-photon annihilation, it is one of the most basic processes in quantum electrodynamics, as well as being ubiquitous in high-energy astrophysics. However, in the 80 years since it was predicted theoretically, this interaction has never been directly observed. Here, I present the design of a new class of photon-photon collider [O. J. Pike et al, Nature Photonics 8, 434 (2014)], which is capable of detecting significant numbers of Breit-Wheeler pairs on current-generation laser facilities. I further discuss our ongoing efforts to implement this scheme in practice.

A photon-photon scattering machine based on twin photo-injectors and Compton sources

• Luca Serafini (MI)

Room: Aula Bruno Touschek We will illustrate a conceptual lay-out for a machine capable to provide two colliding photon beams with energy 0.5-1.5 MeV at high luminosity, in excess of 10^25, so to drive a photon-photon scattering experiment able to produce a few events per day. The machine is quite compact and comprises two high power Yb:Yag collision lasers mutuated from the ELI-NP-GBS project. Strong focusing of the two counter-propagating high brightness electron beams is needed to achieve the required luminosity and proper beam deflection must be applied to avoid contamination from e-/e- interactions. A straw man machine design is presented with predicted costs.

The VIRGO laser light for probing the metric of the space-time

• Fulvio Ricci (ROMA1)

Room: Aula Bruno Touschek

Applied and fundamental physics with ringlasers

• Angela Dora Vittoria Di Virgilio (PI)

Room: Aula Bruno Touschek