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PubblicazioneHydrogen Detachment in Diprotic Aromatics: O–H versus N–H Photodissociation in m-Aminophenol( 2026)While the photochemistry of aromatics with a labile hydrogen atom has been broadly characterized through molecular beam experiments and electronic structure simulations, much less is known regarding the photodissociation of species with more than one exchangeable hydrogen. Fundamental questions like the relative probabilities for the scission of the different X-H bonds, the involved excited states and reaction mechanism, or even the possible photogeneration of diradicals and H2 as a byproduct, remain largely unexplored. On the basis of nonadiabatic molecular dynamics simulations at the TDDFT level, confronted and validated against CASSCF/NEVPT2 calculations, this study addresses these questions for m-aminophenol, a diprotic heteroaromatic compound featuring hydroxyl and amino functions. We find unequal propensities for O-H and N-H dissociation, and the stabilization of the radical products. Data science tools allow us to identify the reaction coordinates leading to dissociation in each case, identifying two very different pathways that result in the observed trends.
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PubblicazioneBounds from D/H on baryogenesis models( 2026)We review the constraints on baryon inhomogeneities derived from measurements of the deuterium abundance, D/H, and apply them to a range of baryogenesis models. In particular, we derive bounds on electroweak baryogenesis as well as on more exotic scenarios. Our results show that, across most of the relevant parameter space, electroweak baryogenesis remains largely unconstrained by current and foreseeable D/H measurements. By contrast, the constraints on alternative scenarios are significantly stronger and can exclude regions of parameter space that would otherwise remain viable.
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PubblicazioneThe Many Guises of Quasiparticles in Correlated Electron Systems(SISSA, 2026-09-14)Many strongly correlated electron systems fall outside the conventional quasiparticle paradigm. Their low-energy fermionic excitations need not be adiabatically connected to the bare electrons or appear as poles of the physical electron single-particle Green's function. This thesis investigates to what extent an effective quasiparticle description can nevertheless survive, and which emergent degrees of freedom provide the appropriate low-energy structure. First, the interaction-driven evolution from a quantum spin Hall insulator to a Mott insulator is studied using the dynamical cluster approximation. Dispersive zeros of the single-particle Green's function emerge near the Mott transition and retain a nontrivial topological character. When symmetry breaking is allowed, a nontopological excitonic insulator is found to intrude between quantum spin Hall and Mott insulators. Encoding both poles and zeros within a low-energy quasiparticle Hamiltonian provides a continuous one-body description of the three phases. On the Mott side, its gap evolution supports interpreting the soft excitonic mode as a bound state of quasiparticle and quasihole excitations tied to the Green's function zeros, rather than to the widely separated Hubbard bands. Second, the intrinsic anomalous Hall conductivity of a topological metal is analyzed within a multiband extension of Landau Fermi-liquid theory. Residual interactions among quasiparticles at the Fermi surface dress the dynamic current vertex and generate corrections to the Berry-curvature contribution obtained from the quasiparticle bands alone. Our result supports recent claims that the correct expressions for topological observables include vertex corrections besides the topological invariants built just upon the Green's function. It also demonstrates that such corrections are naturally accounted for by Landau Fermi-liquid theory. Extracting the relevant ingredients for an effective description of material-relevant correlated systems requires computational tools that remain reliable at low temperatures. To this end, a deterministic strong-coupling impurity solver for dynamical mean-field theory is discussed. By providing static, dynamical, and thermodynamic observables without stochastic sampling, it offers a promising route toward multiorbital and spin-orbit coupled problems where conventional Monte Carlo methods currently struggle. Finally, the auxiliary quasiparticle framework underlying the ghost-Gutzwiller Ansatz is investigated. On a model for correlated quantum spin Hall insulators, we show that the topology of the interacting state is encoded in the auxiliary one-body Hamiltonian. The resulting band-structure reveals topological Hubbard bands whose topological character can be tuned through a finite magnetization. When applied to the single-band t-J model, the same framework yields a fractionalized Fermi liquid (FL*). In this phase, dispersive neutral spinons, with vanishing physical-electron spectral weight, coexist with conventional quasiparticles forming a small hole-like Fermi surface, thus violating Luttinger's theorem. The corresponding temperature--doping phase diagram contains a low-doping FL*, a d-wave superconducting dome, and an overdoped conventional Fermi liquid, thereby reproducing key qualitative features of cuprate phenomenology.
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PubblicazioneConstraints on Primordial Magnetic Fields from the Lyman- α Forest( 2025)We present the first constraints on primordial magnetic fields from the Lyman-alpha forest using full cosmological hydrodynamic simulations. At the scales and redshifts probed by the data, the flux power spectrum is extremely sensitive to the extra power induced by primordial magnetic fields in the linear matter power spectrum, at a scale that we parametrize with k(peak). We rely on a set of more than a quarter million flux models obtained by varying thermal and reionization histories and cosmological parameters. We find a hint of extra power that is well fitted by the primordial magnetic field model with B similar to 0.2 nG, corresponding to k(peak) similar to 20 Mpc(-1). However, when applying very conservative assumptions on the modeling of the noise, we obtain a 3 sigma C.L. lower limit k(peak) >30 Mpc(-1), which translates into the tightest bounds on the strength of primordial intergalactic magnetic fields: B <0.30 nG (for a fixed, nearly scale-invariant n(B) =-2.9).