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Mediante gascromatografia accoppiata alla spettrometria di massa (GC/MS) è stato tracciato il profilo aromatico varietale delle uve Mavrud, Bouquet e Rubin e dei corrispondenti vini ottenuti dalle uve vinificate in purezza. Nelle uve sono stati identificati 33 composti appartenenti alla classe dei benzenoidi, dei terpeni e dei norisoprenoidi; tra i composti più interessanti sono stati trovati il cis e trans-8-OH-linalolo, il p-ment-1-ene-7,8-diolo, il 3-OH-β-damascone, il 3-oxo-α-ionolo, il grassopperchetone e il vomifoliolo. Nelle frazioni volatili libere dei vini sono stati identificati circa 60 composti, per la gran parte composti di fermentazione quali esteri, acetati, alcoli, benzenoidi e lattoni, oltre a terpeni e norisoprenoidi varietali. Nella frazione legata dei vini, ottenuta dopo idrolisi enzimatica sono stati trovati 30 composti varietali.

The structural phase transition in Ta2NiSe5 has been envisioned as driven by the formation of an excitonic insulating phase. However, the role of structural and electronic instabilities on crystal symmetry breaking has yet to be disentangled. Meanwhile, the phase transition in its complementary material Ta2NiS5 does not show any experimental hints of an excitonic insulating phase. We present a microscopic investigation of the electronic and phononic effects involved in the structural phase transition in Ta2NiSe5 and Ta2NiS5 using extensive first-principles calculations. In both materials the crystal symmetries are broken by phonon instabilities, which in turn lead to changes in the electronic bandstructure also observed in the experiment. A total energy landscape analysis shows no tendency towards a purely electronic instability and we find that a sizeable lattice distortion is needed to open a bandgap. We conclude that an excitonic instability is not needed to explain the phase transition in both Ta2NiSe5 and Ta2NiS5. [ABSTRACT FROM AUTHOR]

Many-body models undergoing a quantum phase transition to a broken-symmetry phase that survives up to a critical temperature must possess, in the ordered phase, symmetric as well as nonsymmetric eigenstates. We predict, and explicitly show in the fully connected Ising model in a transverse field, that these two classes of eigenstates do not overlap in energy, and therefore that an energy edge exists separating low-energy symmetry-breaking eigenstates from high-energy symmetry-invariant ones. This energy is actually responsible, as we show, for the dynamical phase transition displayed by this model under a sudden large increase of the transverse field. A second situation we consider is the opposite, where the symmetry-breaking eigenstates are those in the high-energy sector of the spectrum, whereas the low-energy eigenstates are symmetric. In that case too a special energy must exist marking the boundary and leading to unexpected out-of-equilibrium dynamical behavior. An example is the fermonic repulsive Hubbard model Hamiltonian H. Exploiting the trivial fact that the high-energy spectrum of Ti is also the low-energy one of -- H, we conclude that the high-energy eigenstates of the Hubbard model are superfluid. Simulating in a time-dependent Gutzwiller approximation the time evolution of a high-energy BCS-like trial wave function, we show that a small superconducting order parameter will actually grow in spite of the repulsive nature of the interaction. [ABSTRACT FROM AUTHOR]

Ta2NiSe5 is one of the most promising materials for hosting an excitonic insulator ground state. While a number of experimental observations have been interpreted in this way, the precise nature of the symmetry breaking occurring in Ta2NiSe5, the electronic order parameter, and a realistic microscopic description of the transition mechanism are, however, missing. By a symmetry analysis based on first-principles calculations, we uncover the discrete lattice symmetries which are broken at the transition. We identify a purely electronic order parameter of excitonic nature that breaks these discrete crystal symmetries and contributes to the experimentally observed lattice distortion from an orthorombic to a monoclinic phase. Our results provide a theoretical framework to understand and analyze the excitonic transition in Ta2NiSe5 and settle the fundamental questions about symmetry breaking governing the spontaneous formation of excitonic insulating phases in solid-state materials. [ABSTRACT FROM AUTHOR]

There is currently great interest in the strong coupling between the quantized photon field of a cavity and electronic or other degrees of freedom in materials. A major goal is the creation of novel collective states entangling photons with those degrees of freedom. Here we show that the cooperative effect between strong electron correlations in quantum materials and the long-range interactions induced by the photon field leads to the stabilization of coherent phases of light and matter. By studying a two-band model of interacting electrons coupled to a cavity field, we show that a phase characterized by the simultaneous condensation of excitons and photon superradiance can be realized, hence stabilizing and intertwining two collective phenomena which are rather elusive in the absence of this cooperative effect. [ABSTRACT FROM AUTHOR]

We study the crossover between the sudden quench limit and the adiabatic dynamics of superconducting states in the attractive Hubbard model. We focus on the dynamics induced by the change of the attractive interaction during a finite ramp time. The ramp time is varied in order to track the evolution of the dynamical phase diagram from the sudden quench to the equilibrium limit. Two different dynamical regimes are realized for quenches towards weak and strong coupling interactions. At weak coupling the dynamics depends only on the energy injected into the system, whereas a dynamics retaining memory of the initial state takes place at strong coupling. We show that this is related to a sharp transition between a weak and a strong coupling quench dynamical regime, which defines the boundaries beyond which a dynamics independent from the initial state is recovered. Comparing the dynamics in the superconducting and nonsuperconducting phases, we argue that this is due to the lack of an adiabatic connection to the equilibrium ground state for nonequilibrium superconducting states in the strong coupling quench regime. [ABSTRACT FROM AUTHOR]

We investigate the formation of nonequilibrium superconducting states in driven alkali-doped fullerides A3C60. Within a minimal three-orbital model for the superconductivity of these materials, it was recently demonstrated theoretically that an orbital-dependent imbalance of the interactions leads to an enhancement of superconductivity at equilibrium [M. Kim et al., Phys. Rev. B 94, 155152 (2016)]. We investigate the dynamical response to a time-periodic modulation of this interaction imbalance and show that it leads to the formation of a transient superconducting state which survives much beyond the equilibrium critical temperature Tc. For a specific range of frequencies, we find that the driving reduces superconductivity when applied to a superconducting state below Tc while still inducing a superconducting state when the initial temperature is larger than Tc. These findings reinforce the relevance of the interaction-imbalance mechanism as a possible explanation of the recent experimental observation of light-induced superconductivity in alkali-doped fullerenes. [ABSTRACT FROM AUTHOR]