ERC FUNDED PROJECTS

"The proposed research program has three main objectives. The first and second objectives are to seek extreme precisions in optical atomic spectroscopy and optical clocks, and to use this quest as a mean of exploration in atomic physics. The third objective is to explore new possibilities that stem from extreme precision. These goals will be pursued via three complementary activities: #1: Search for extreme precisions with an Hg optical lattice clock. #2: Explore and exploit the rich Hg system, which is essentially unexplored in the cold and ultra-cold regime. #3: Identify new applications of clocks with extreme precision to Earth science. Clocks can measure directly the gravitational potential via Einstein’s gravitational redshift, leading to the idea of “clock-based geodesy”. The 2 first activities are experimental and build on an existing setup, where we demonstrated the feasibility of an Hg optical lattice clock. Hg is chosen for its potential to surpass competing systems. We will investigate the unexplored physics of the Hg clock. This includes interactions between Hg atoms, lattice-induced light shifts, and sensitivity to external fields which are specific to the atomic species. Beyond, we will explore the fundamental limits of the optical lattice scheme. We will exploit other remarkable features of Hg associated to the high atomic number and the diversity of stable isotopes. These features enable tests of fundamental physical laws, ultra-precise measurements of isotope shifts, measurement of collisional properties toward evaporative cooling and quantum gases of Hg, investigation of forbidden transitions promising for measuring the nuclear anapole moment of Hg. The third activity is theoretical and is aimed at initiating collaborations with experts in modelling Earth gravity. With this expertise, we will identify the most promising and realistic approaches for clocks and emerging remote comparison methods to contribute to geodesy, hydrology, oceanography, etc."

1 946 432 €

Start date: 2014-04-01, End date: 2019-03-31

"In the comprehension of fundamental laws of nature, particle physics is now facing two important questions: 1) What is the nature of the neutrino, is it a standard (Dirac) particle or a Majorana particle? The nature of the neutrino plays a crucial role in the global framework of particle interactions and in cosmology. The only practicable way to answer this question is to search for a nuclear process called ""neutrinoless double beta decay"" (0nuDBD). 2) What is the so called ""dark matter"" made of? Astrophysical observations suggest that the largest part of the mass of the Universe is composed by a form of matter other than atoms and known matter constituents. We still do not know what dark matter is made of because its rate of interaction with ordinary matter is really low, thus making the direct experimental detection extremely difficult. Both 0nuDBD and dark matter interactions are rare processes and can be detected using the same experimental technique. Bolometers are promising devices and their combination with light detectors provides the identification of interacting particles, a powerful tool to reduce the background. 
 The goal of CALDER is to realize a new type of light detectors to improve the upcoming generation of bolometric experiments. The detectors will be designed to feature unprecedented energy resolution and reliability, to ensure an almost complete particle identification. In case of success, CUORE, a 0nuDBD experiment in construction, would gain in sensitivity by up to a factor 6. LUCIFER, a 0nuDBD experiment already implementing the light detection, could be sensitive also to dark matter interactions, thus increasing its research potential. The light detectors will be based on Kinetic Inductance Detectors (KIDs), a new technology that proved its potential in astrophysical applications but that is still new in the field of particle physics and rare event searches."

1 176 758 €

Start date: 2014-03-01, End date: 2019-02-28

"With the ground-breaking discovery of a new, Higgs-like boson on July 4th, 2012, by the CMS and ATLAS collaborations at CERN, a new era of particle physics has begun. The discovery is the first step in answering an unsolved problem in particle physics, the question how fundamental bosons and fermions acquire their mass. One of the major goals in collider physics in the next few years will be the deeper insight into the nature of the new particle, its connection to the known fundamental particles and possible extensions beyond the standard model (SM) of particle physics. My project aims at a particular interesting field to study, the relation of the new particle with the heaviest known elementary particle, the top quark. I aim to develop new, innovative techniques and beyond state-of-the-art methods to extract the Yukawa coupling between the top quark and the Higgs boson, which is expected to be of the order of one - much higher than that of any other quark. I will analyse the only process where the top-Higgs Yukawa coupling can be measured, in associated production of top quark pairs and a Higgs boson. The Higgs boson mainly decays into a pair of b-quarks. This is one of the most challenging channels at the LHC, as huge background processes from gluon splitting contribute. In particular, I will develop and study color flow variables, which provide a unique, powerful technique to distinguish color singlet Higgs bosons from the main background, color octet gluons. The ultimate goal of the project is the first measurement of the top-Higgs Yukawa coupling and its confrontation with SM and beyond SM Higgs boson models, resulting in an unprecedented insight into the fundamental laws of nature. The LHC will soon reach a new energy frontier of 13 TeV starting in 2014. This new environment will provide never seen opportunities to study hints of new physics and precisely measure properties of the newly found particle. This sets the stage for the project."

1 163 755 €

Start date: 2014-02-01, End date: 2019-01-31

Quantum field theory (QFT) is a unified conceptual and mathematical framework that encompasses a veritable cornucopia of physical phenomena, including phase transitions, condensed matter systems, elementary particle physics, and (via the holographic principle) quantum gravity. QFT has become the standard language of modern theoretical physics. Despite the fact that QFT is omnipresent in physics, we have virtually no tools to analyze from first principles many of the interesting systems that appear in nature. (For instance, Quantum Chromodynamics, non-Fermi liquids, and even boiling water.) Our main goal in this proposal is to develop new tools that would allow us to make progress on this fundamental problem. To this end, we will employ two strategies. First, we propose to study in detail systems that possess extra symmetries (and are hence simpler). For example, critical systems often admit the group of conformal transformations. Another example is given by theories with Bose-Fermi degeneracy (supersymmetric theories). We will explain how we think significant progress can be achieved in this area. Advances here will allow us to wield more analytic control over relatively simple QFTs and extract physical information from these models. Such information can be useful in many areas of physics and lead to new connections with mathematics. Second, we will study general properties of renormalization group flows. Renormalization group flows govern the dynamics of QFT and understanding their properties may lead to substantial developments. Very recent progress along these lines has already led to surprising new results about QFT and may have direct applications in several areas of physics. Much more can be achieved. These two strategies are complementary and interwoven.

1 158 692 €

Start date: 2013-09-01, End date: 2018-08-31