Research

Whats is the energy scale of inflation? What about its particle content?
Going beyond the current broad-brush picture of inflation has immense discovery potential for cosmology and particle physics alike. The energies at play, likely many orders of magnitude above those accessible via particle colliders, make cosmological probes of inflation the best available portal onto high energy physics, an ideal testing bed for (beyond) Standard Model physics and, possibly, quantum gravity.

I work on inflationary model building,  using different approaches to uncover the particle content of the very early universe. My research pairs up the focus on specific classes of models, such as axion inflation, with the more agnostic approach afforded by the use of effective field theory techniques. I complement these efforts on model building with the exploration of the signatures associated to the inflationary field content, with a special focus on primordial gravitational waves (GW). 

There is a lot we can learn from primordial GW spectral shape, chirality, non-Gaussianities. I have been also pursuing the study of GW anisotropies as an additional handle on inflationary interactions. I am a full member of the LISA Collaboration, actively involved in the activities of the Cosmology Working Group. I am part of the Cosmology and Fundamental Physics Divisions of the Einstein Telescope.

Key words & papers: inflation, primordial gravitational waves, non-Gaussianity, inflationary particle content, "fossil" fields, cosmological collider physics, axion-inflation, axion-gauge fields dynamics, anisotropies, multi-messenger cosmology
( See related publications: [1], [2], [3], [4], [7], [8], [9], [10], [11], [14], [15], [17], [19], [22], [24], [25], [26], [28], [29], [31], [32], [33], [35], [36], [37], [38], [39], [40], [42], *[20], [44], [47], [50], [52], [54] )

I have been contributing to perturbative approaches to the study of structure formation. The linear regime is under full perturbative control. Recently, there has been a great effort in the community to extend the reach of analytical approaches to the mildly non-linear (or quasi-linear) regime. The number of available modes grows steeply, like k^3, making any progress on kmax a tremendous opportunity to discover new physics (from primordial non-Gaussianities to dark energy). Despite their being intrinsically limited in the momentum reach, the availability of perturbative approaches makes it possible to include in the description the complex set of layers characterising LSS dynamics: from initial conditions set by inflation to baryons, from redshift space distortions to the presence of a dark energy component. It is vital that we develop such tools and pair them up with state-of-the-art simulations. I have been developing perturbative approaches to include the effect of primordial non-Gaussianities and a dark energy component.

Key words & papers: EFT of LSS, non-Gaussianity in the EFT of LSS, LSS dynamics in the presence of dark energy/modified gravity
( See related publications: [18] , [22], [23], [30], *[15], *[19], *[21], *[29], [30], [51], [53] )

The cosmological constant, dark energy (DE), and IR modifications (MG) of general relativity have all been enlisted to make sense of the mechanism driving late-time cosmic acceleration. The quest for an ultimate answer to this question drives a large part of modern research in cosmology and is bound to be transformative of our understanding of how cosmology stems from fundamental physics. Further evidence for the cosmological constant, Λ, would call into question the central paradigm of technical naturalness: how may one explain the large hierarchy between the expected contributions to vacuum energy from Standard Model particles and its tiny observed value? Would we have to resort to anthropic arguments? My research lies at the heart of these challenges.  I have worked on massive theories of gravity as an alternative mechanism for late-time acceleration. I set powerful criteria on the existence of stable & viable cosmological solutions and explored screening dynamics in large scale structure settings.
Key words & papers:  ΛCDM, dark energy, modified gravity, screening mechanisms, massive gravity
( See related publications: [5], [6], [12], [13], [16], [20], [21], [34], *[22], *[23], *[24], *[25], *[30], [34], [46] ) 

Effective field theory, perturbative approaches

CMB (LiteBIRD, CMB-S4,...), Large Scale Structure (Euclid, LSST, SKA,...), Interferometers (LIGO&Virgo, LISA, Einstein Telescope...) , cross-correlations