ERC FUNDED PROJECTS

The aim of this proposal is to develop a novel laser-spectroscopy method and to study nuclear and atomic properties of heaviests elements in order to address the following key questions: - Is the existence of the heaviest isotopes determined by the interplay between single-particle and collective nucleon degrees of freedom in the atomic nucleus? - How do relativistic effects and isotopic composition influence the valence atomic structure of the heaviest elements? The new approach is based on in-gas jet, high-repetition, high-resolution laser resonance ionization spectroscopy of short-lived nuclear-reaction products stopped in a buffer gas cell. The final goal is to couple the new system to the strongest production facility under construction at the ESFRI-listed SPIRAL-2 facility at GANIL (France) and to study isotopes from actinium to nobelium and heavier elements. An increase of the primary intensity, efficiency, selectivity and spectral resolution by one order of magnitude compared to present-day techniques is envisaged, which is essential to obtain the required data . The challenges are: - decoupling the high-intensity heavy ion production beam (> 10^14 particles per second) from the low-intensity reaction products (few atoms per second) - cooling of the reaction products from MeV/u to meV/u within less then hundred milliseconds - separating the wanted from the, by orders of magnitude overwhelming, unwanted isotopes - performing high-resolution laser spectroscopy on a minute amount of atoms in an efficient way. Nuclear properties (charge radii, nuclear moments and spins) as well as atomic properties (transition energies and ionization potentials) will be deduced in regions of the nuclear chart where they are not known: the neutron-deficient isotopes of the actinide elements, up to nobelium (Z = 102) and beyond. The data will validate state-of-the-art calculations, identify critical weaknesses and guide further theoretical developments.

2 458 397 €

Start date: 2012-03-01, End date: 2017-02-28

A serious open issue is that there is no widely accepted solution to the Quantum Gravity Problem. This results in paradoxes and clouds the study of many problems from the cosmology of the early Universe to unified theories of fundamental interactions that should incorporate both the Standard Model of Elementary Particles and Gravity. This proposal aims at attacking the old problems from a new vantage point and to achieve long-awaited breakthroughs. The potential reward is enormous as the project aims to shed light on the wide range of problems by exploring a new avenue provided by the first working example of a Higher Spin Gravity (HiSGRA). It will (A) attack the Quantum Gravity Problem and give new consistent theories that should significantly extend our understanding; (B) the underlying higher spin symmetry should govern a number of condensed matter systems and we expect to prove the recently discovered remarkable dualities relating them; (C) these symmetries are also related to extensions of Deformation Quantization, which should lead to new developments in pure mathematics and consolidate A+B. HiSGRA's, as rather simple models, can give keys to the puzzles of the early Universe with potentially observable effects in the near future, to the old paradoxes of black hole physics and to real-world processes of black hole scattering, which together with B applies HiSGRA to physics. This project is timely and feasible thanks to the recent ground-breaking results obtained by me and collaborators: (1) the very first example of a quantum consistent HiSGRA has been constructed and shown not to suffer from the UV-divergences that are at the core of the Quantum Gravity Problem; (2) the same theory was instrumental in attacking the dualities in three-dimensional conformal field theories that govern the physics of many second-order phase transitions; (3) it made new verifiable predictions for correlation functions, which is the very first solid prediction from HiSGRA

1 992 507 €

Start date: 2021-09-01, End date: 2026-08-31

One of the major challenges in theoretical physics is the development of systematic methods for describing and simulating quantum many body systems with strong interactions. Given the huge experimental progress and technological potential in manipulating strongly correlated atoms and electrons, there is a pressing need for such a better theory. The study of quantum entanglement holds the promise of being a game changer for this question. By mapping out the entanglement structure of the low-energy wavefunctions of quantum spin systems on the lattice, the prototypical example of strongly correlated systems, we have found that the associated wavefunctions can be very well modeled by a novel class of variational wavefunctions, called tensor network states. Tensor networks are changing the ways in which strongly correlated systems can be simulated, classified and understood: as opposed to the usual many body methods, these tensor networks are generic and describe non-perturbative effects in a very natural way. The goal of this proposal is to advance the scope and use of tensor networks in several directions, both from the numerical and theoretical point of view. We plan to study the differential geometric character of the manifold of tensor network states and the associated nonlinear differential equations of motion on it, develop post tensor network methods in the form of effective theories on top of the tensor network vacuum, study tensor networks in the context of lattice gauge theories and topologically ordered systems, and investigate the novel insights that tensor networks are providing to the renormalization group and the holographic principle. Colloquially, we believe that tensor networks and the theory of entanglement provide a basic new vocabulary for describing strongly correlated quantum systems, and the main goal of this proposal is to develop the syntax and semantics of that new language.

1 927 500 €

Start date: 2015-09-01, End date: 2021-08-31

Despite its considerable success, Einstein theory of gravity is an unfinished revolution: it has limitations both at the microscopic scales and at the macroscopic scales. The objective of this proposal is to provide a better understanding of the gravitational interaction beyond Einstein. This will be done by analyzing, with the aim of identifying it, the symmetry structure underlying the searched-for fundamental formulation of gravity, relying on and exploring further the intriguing and fascinating infinite-dimensional algebras uncovered recently in the study of supergravities and M-theory. One of the motivations of the project is to make progress in the development of quantum gravity, with the goal of providing new insight into black holes and cosmological singularities.

1 511 556 €

Start date: 2011-01-01, End date: 2015-12-31