### Nuclear Physics with ab initio few-body methods

Nuclei are the most common manifestation of Quantum Chromo-Dynamics (QCD) in the non-perturbative regime. A description of these systems that starts from the mutual interaction of quarks is still in a semi-qualitative status. An economic but realistic representation can be obtained by considering them as composed by "effective" structureless constituents, protons, neutrons or hyperons, interacting through "effective" mutual forces which are the results of the complicated underlying dynamics and symmetries. In this seminarI will illustrate with some examples the two goals that nowadays are pursued by the few-body community i) an accurate description of those forces and of their two- or three-body nature and ii) the dependence on them of typical many-body phenomena. The two goals are pursued by comparing to data results obtained solving the A baryon quantum mechanical problem with high accuracy. The importance of ab initio nuclear physics results as inputs for other fields will also be illustrated.

**Friday, 10 June 2016, ore 14:30 — Sala Wataghin **

In this talk I will describe some novel formulations for scattering amplitudes in maximally supersymmetric Yang-Mills theory in four dimensions. Very recently it has been conjectured that amplitudes in planar N=4 SYM are nothing else but the volume of a completely new mathematical object, called amplituhedron, which generalises the positive Grassmannian. After a broad review of the main ingredients involved, I will discuss some of the questions which remain open in this framework and describe new directions which promise to solve these issues.

**Friday, 27 May 2016, ore 14:30 — Aula A **

### Quantum Twists of Space

Estimates are presented of exotic correlations of rotation on large scales that could emerge from effects of quantum geometry at the Planck length. Extrapolation of standard quantum theory and gravity suggests that a constant direction in the inertial frame fluctuates relative to distant space by an amount that decreases on larger scales. Exotic correlations in the phase of propagating fields are estimated using a statistical model based on Planck scale elements correlated on causal boundaries around an observer. Projection of exotic correlation onto an interferometer signal correlation function is estimated, and shown to vanish unless the light path sweeps out a nonzero spatial area. It is conjectured that exotic rotational correlations could resolve conflicts of field theory with gravity on large scales, and that entanglement with the Standard Model field vacuum might account for the value of the cosmological constant.

**Wednesday, 25 May 2016, ore 14:30 — Sala Wataghin **

### Tetraquarks, Pentaquarks and All That

I will review the experimental and theoretical status of the so called XYZ spectroscopy of exotic hadrons with particular attention to open questions and most recent findings. The existence of seemingly contradictory pictures to explain their nature partly reflects the ignorance about the exact solutions of non-perturbative QCD.

**Friday, 13 May 2016, ore 14:30 — Sala Wataghin **

### Charge-changing and Neutral Current Neutrino Interactions with Nuclei

Recent progress in modeling CC and NC neutrino reactions with nuclei at both low and high energies will be summarized. Various issues will be discussed: the importance of relativistic modeling for high-energy reactions; the delicate interplay of the necessary contributions in the relevant kinematic regions (quasielastic (QE), meson-exchange current (MEC) and inelastic contributions); the critical role played by validating modeling through comparisons with inclusive electron scattering, including the most recent tests of the so-called SuSAv2-MEC approach versus a large set of data spanning energies from a few 100 MeV to several GeV; the general formalism for semi-inclusive CC neutrino reactions; the special role that can be played by studies of CC neutrino reactions on deuterium; coherent NC neutrino scattering and its close relationship with elastic parity-violating electron scattering from nuclei.

**Friday, 29 April 2016, ore 14:30 — Sala Wataghin **

### Gravitational-wave detection: status and perspectives

The detection of gravitational waves, predicted exactly 100 years ago by Albert Einstein, opens a totally new field of the universe exploration and will have a deep impact on the future of astrophysics observations. On September 14, 2015 at 09:50:45 UTC, for the first time a transient gravitational-wave signal has been observed. The signal matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The talk will discuss the path that led to the discovery and the new perspectives opened in the field.

**Friday, 15 April 2016, ore 14:30 — Aula Magna **

### Searching for life in the universe: how, where and why?

The age-old question "Are we alone in the universe?" has attracted renewed interest in recent years. The discovery of the first extrasolar planet around a sun-like star, two decades ago, ushered in an era of unprecedented activity in astrobiology, the interdisciplinary science that seeks to characterize the limits and frequency of life in the cosmic context. Much work has been done - and much still needs to be done - to assess the factors that make a world habitable and to devise techniques that, in the not too distant future, might be used to remotely characterize exoplanets and their atmospheres, looking for the tell-tale signatures of biological activity. The long-sought goal of empirically evaluating the distribution of life in the universe might have a profound impact also on our understanding of the fundamental structure of our universe.

**Friday, 1 April 2016, ore 14:30 — Aula Magna **

### Quantum entanglement: from a conclusive test of Bell inequalities to quantum tech

Quantum entanglement has represented for more than 70 years a source of debate about foundations of quantum mechanics. This research culminated last year with the loophole free tests of Bell inequalities, confirming quantum non-locality. Furthermore, the development of these studies paved the way to practical applications addressed to developing new technologies based on peculiar properties of quantum states: the quantum tech. This offers an emblematic example of the success of "curiosity driven" research, leading to applications not imaginable or attainable with "goal oriented" research.

**Friday, 18 March 2016, ore 14:30 — Aula Magna **

### The physics of jamming: a journey from marble pebbles toward scaling invariant field theory

Jamming is a well know phenomenon that you have experienced when the traffic is very heavy. You cannot move because your neighbours block you and your neighbors cannot move because you block them. Jamming is a collective phenomenon. Marble pebbles on the beach are one example of jamming. However also for well-levigated pebbles, friction will play an important role. Statistical mechanics may be used to study the case of systems without friction. The most studied case is the hard sphere gas where the jamming point is reached in the limit of infinite pressure. In the case of frictionless jamming long-range correlations are present: we have a new kind of critical system. Recently the properties of the hard sphere gas have been analytically computed in the framework of the mean field approximation. Non-trivial critical exponents have been found. The behavior of the correlation functions at large distances has not yet computed (it is technically very challenging): at the end one should find a new scaling invariant (and quite likely conformal invariant) field theory

**Friday, 4 March 2016, ore 14:30 — Aula Magna **

### Neutrino masses and oscillations

The current status of neutrino masses and oscillations is reviewed.
The most important open problems in neutrino physics are discussed: the mass ordering, the absolute mass scale, the Dirac-Majorana nature of neutrinos, the hints in favor of the existence of sterile neutrinos.

**Friday, 26 February 2016, ore 14:30 — Sala Wataghin **