Tag Archives: Evento scientifico

In the last decade, the development/proposal of MHz-class repetition rate electron applications such as free electron lasers (FELs), inverse Compton scattering sources, and ultrafast electron diffraction and microscopy (UED/UEM), called for the development of new gun schemes capable of generating high brightness beams at such high rates. The VHF-Gun, a 186 MHz room-temperature continuous wave RF photo-gun developed at the Lawrence Berkeley Laboratory (LBNL) was one of the answers to that call. The VHF-Gun was constructed and tested in the APEX facility at LBNL successfully demonstrating all design parameters and the generation of electron beams with the required brightness. A close version of the APEX VHF-Gun was fabricated at LBNL and delivered to SLAC to operate as the electron source for the LCLS-II, the new X-ray FEL in construction at Stanford, and the original VHF-Gun is presently used for generating the beams for HiRES, the UED program at LBNL. But the game it is not over yet! For example, the recently approved upgrade of the LCLS-II towards higher energies (LCLS-II HE), and the always brightness-starving UED and UEM applications, would greatly benefit from a further increase of the electron beam brightness. In response to that, our group at LBNL started to study possible upgrades of the VHF-Gun scheme that would allow for the desired performance improvement. Several conceptual options were identified and last year, we received funds for developing such concepts up to a more mature level. After a description of the existing VHF-Gun and of its main experimental results, …

Abstract: Pomeron is a term introduced in the 1960’s in the frame- work of the phenomenological Regge theory. It describes the behavior of total cross-sections of any hadronic reaction at extremely large values of the invariant energy s. In the QCD context, the best-known contribution to the Pomeron comes from the BFKL equation This approach resums Leading Logarithmic (LL) contributions i.e. single-logarithmic (SL) contributions, ∼ (αs ln s)n, multiplied by the overall factor s. The high-energy asymptotics of this resummation is known as the BFKL Pomeron. It predicts the total cross-section of hadronic reactions (and the γγ-scattering in particular) to behave, asymptotically, as ∼ s∆, where the exponent ∆ is called the intercept of the BFKL Pomeron. In contrast, we calculate amplitude ADL of elastic γγ-scattering in the Double-Logarithmic approximation (DLA), accounting for contributions ∼ (αs ln2 s)n. They are not accompanied by the overall factor s, so asymptotics of ADL is ∼ s(∆DL−1) which looks negligibly small compared to the BFKL result. By this reason the DL contribution to Pomeron was offhandedly ignored by theoretical HEP society and full attention was focused on the BFKL Pomeron only. However, we demonstrate that the intercept ∆DL proves to be so large that its value compensates for the lack of the extra factor of s and makes the DL Pomeron of comparable importance to the BFKL Pomeron. It means that DL Pomeron should participate in theoretical analysis of all HEP results where the BFKL Pomeron has been involved.

Today, high brightness and highly relativistic electron beams are generated by circular or linear accelerators (LINAC) typically operating with 1-3 GHz accelerating frequencies and approaches towards X-band frequencies in the 10 GHz range are maturing. The achievable accelerating gradients are limited by field emission from cavity walls or pulsed heating to several tens of MV/m in the case of low frequencies and up to 100 MV/m in the case of X- band frequencies. Moving up in frequency to the THz range, here hundreds of GHz, experimentally confirmed scaling laws predict the realization of few-hundred MV/m to 1 GV/m accelerating fields in LINACs and guns, respectively. The high field strength and field gradients enable direct generation of single femtosecond electron bunches with substantial charge in the pC-range from very compact devices. We will discuss highly efficient laser based THz generation by optical rectification and first results towards THz based electron guns, LINACs and beam manipulations with the final goal to construct a hard-X-ray source producing attosecond pulses.

L’INFN e i Laboratori Nazionali di Frascati portano avanti una intensa attività di ricerca tecnologica i cui prodotti, oltre che nella ricerca fondamentale, trovano applicazione in diversi campi di interesse sia sociale che industriale. In questo ciclo di seminari, dedicati ognuno a tecnologie e infrastrutture di interesse per un determinato settore, i LNF vogliono continuare il dialogo aperto con altri Enti, Università, Istituzioni ed Imprese in occasione dell’Open Day Imprese a Giugno 2017.   LNF e le tecnologie per lo SPAZIO: Laboratori di test e calibrazione Ai LNF operano alcuni laboratori capaci di fornire test e calibrazione di strumenti, dispositivi e componenti per applicazioni spaziali. Queste attività riguardano strumenti per la telemetria e altimetria laser, test ambientali per cubo- e micro-satelliti, radiazioni di sincrotrone nel visibile, UV, infrarosso, raggi X, fotoni gamma, elettroni e positroni. L’attività è condotta in partnership istituzionali tra INFN e NASA-SSERVI (Solar System Exploration Research Virtual Institute) e ASIF (ASI Supported Irradiation Facilities). Coordina: S. Dell’Agnello Prossimo Seminario Le tecnologie di magneti e vuoto: infrastrutture e servizi – Febbraio 2019

Starting from the original experiment performed by Henry Cavendish more than two centuries ago, the precision determination of the gravitational constant G remains a challenging endeavor. It has been measured about a dozen times over the last 50 years, but the results have varied much more than what would be expected from random and systematic errors. Likely, this is due to the fact that, so far, all the past experiments have relied on macroscopic classical instruments, which could all be governed by uncontrolled mechanical influences. On the other hand, a recent controversial study about correlations between the measured values of G and the variations of the length of day seems to suggest that some other not well-understood effects could be present. The MEGANTE experiment (ERC-StG-2018 hosted by INFN) will address all these issues by carrying out precision G determinations making use of original experimental strategies based on quantum sensors. Unprecedented accuracy levels will be achieved using cold atoms in free-fall to probe the gravitational field, surpassing thus the state-of-art measurements based on torsion balance and simple pendulum. In parallel, MEGANTE will provide results that go far beyond the pure metrological interest. Indeed, owing the lack of a full understanding of gravity, several theoretical models predict new physics phenomena such violations of the inverse square law or a dependency of the G value from the local density of the matter. In the present talk I will present all the scientific and technical challenges that are needed to be faced in order …

In this seminar, I will discuss the applications of linear and non-linear stochastic Schroedinger equations in quantum foundations as well as in the study of transport phenomena in open quantum systems. In quantum foundations, non-linear stochastic Schroedinger equations play a fundamental role in collapse models. In these models, the wavefunction collapse in space is described by a non-linear interaction with an external classical noise, resolving the measurement problem. From a mathematical point of view, the evolution of the state of the system is described by a class of non-linear stochastic Schroedinger equations, which will be discussed. Transport phenomena in open quantum systems are relevant in a large class of interesting systems. The study of the dynamics of a chain of harmonic oscillators locally connected to baths at an arbitrary temperature will be discussed. The advantages of solving the system dynamics using stochastic unravellings instead of working directly with the master equation will be highlighted. The study is relevant in the field of quantum thermodynamics as well as for exciton transfer in biological networks.

Recent progress in solid-state cavity-QED with semiconductor quantum dots enables efficient photonic quantum gates. Apart from studies of fundamentally new cavity QED effects, those systems allow the generation of high-brightness quantum light in Fock space at a strongly reduced experimental complexity. This opens up, for instance, a new kind of “quantum-light spectroscopy” that was not possible before, with applications and in order to address open questions in bio-molecular spectroscopy and microscopy. At the same time, the quantum dot cavity-QED systems can be used to create large entangled states involving potentially several tens of photons in a deterministic way, avoiding post-selection and therefore much more efficient exploration of those highly entangled systems, cluster and graph states, first steps in this direction will be shown.

Overview Image taken from http://discovermagazine.com/2014/dec/17-this-quantum-life   The main aim of the “New Quantum Horizons: From Foundations To Biology” Symposium is to discuss in an informal and friendly environment theoretical and experimental issues related to quantum physics, from foundational issues (such as connection between gravity and quantum physics, collapse models, spin-statistics) to applicative aspects, including new findings and ideas to investigate quantum effects in biological systems. The Symposium is supported by the Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma and by LNF-INFN. Conference Organizer: Catalina Curceanu, Laboratori Nazionali di Frascati, INFN, Italy Beatrix Hiesmayr, University of Vienna, Vienna, Austria Local Organizing Committee: A. Scordo, Laboratori Nazionali di Frascati, INFN, Italy A. Tamborrino Orsini, Laboratori Nazionali di Frascati, INFN, Italy

WIMPs mostly interacting with the SM states through a pseudoscalar mediator can achieve the correct relic density evading current constraints from Dark Matter Direct Detection. I will discuss some realistic implementation for a dark pseudoscalar portal with particular focus to the prospects for Direct Detection at next future facilities.