Gianluca Gregori

Abstract:

We propose a new method for detecting high frequency gravitational waves (GWs) using high energy pulsed lasers. Through the inverse Gertsenshtein effect, the interaction between a GW and the laser beam results in the creation of an electromagnetic signal. The latter can be detected using single-photon counting techniques. We compute the minimal strain of a detectable GW which only depends on the laser parameters. We find that a resonance occurs in this process when the frequency of the GW is twice the frequency of the laser. With this method, the frequency range $10^{13}-10^{19} $ Hz is explored non-continuously for strains $h \gtrsim 10^{-20}$ for current laser systems and can be extended to $h \gtrsim 10^{-26}$ with future generation facilities.

Abstract:

In this paper, taking start from some verses of the Aeneid, the Author will focus on some literary and epigraphic documents in search for evidence of the geographical and ethnic references in Virgilian poem. In particular, there will be taken into account the passages and inscriptions which celebrate Rome's territorial expansionism and her dominion up to the borders of the known world thanks to Augustus, as the prince himself proudly declares in the chapter 26 of his Res gestae. The paper is structured in three sections: 1. Prophecies and divine promises in the Aeneid. 2. Possible historical references in the Aeneid. 3. Possible historical evidence in Latin inscriptions. In none of the other Latin poets active in the decade between 30 and 20 BC we find so frequent and explicit references to the military glories of Augustan Rome, with so many citations of peoples, lands, rivers and seas. This could not be conventional: if the historical references present in the Aeneid actually recall historical events, then the portrait of Virgil as a singer of Augustus' praises would be strengthened, and the utilitarian character of Roman poetry would be confirmed.

Abstract:

Inductively-coupled plasma discharges are well-suited as plasma sources for experiments in fundamental high-energy density science, which require large volume and stable plasmas. For example, experiments studying particle beam-plasma instabilities and the emergence of coherent macroscopic structures — which are key for modelling emission from collisionless shocks present in many astrophysical phenomena. A meter-length, table-top, inductive radio-frequency discharge has been constructed for use in a high-energy density science experiment at CERN which will study plasma instabilities of a relativistic electron-positron beam. In this case, a large volume is necessary for the beam to remain inside the plasma as it diverges to centimeter-scale diameters during the tens-of-centimeters of propagation needed for instabilities to develop. Langmuir probe measurements of the plasma parameters show that plasma can be stably sustained in the discharge with electron densities exceeding 1011 cm-3. The discharge has been assembled using commercially-available components, making it an accessible option for commissioning at a University laboratory.