G. Preparata’s research while affiliated with University of Milan and other places

In the framework of a novel approach to the dynamics of nuclei and large collections of nucleons, which fully exploits the coherent interaction among π’s, nucleons and Δ’s, we derive a new equation of state for neutronic matter. By introducing it in the Tolman-Oppenheimer-Volkof equations we derive the masses and radii of neutron stars as a function of the central density. We obtain a maximum mass M max ≃2.7 M ʘ and a minimum period of rotation T min =0.8 msec.

We show that a correct analysis of the gauge-invariance properties of the em coupling of atomic systems with single-mode em radiation fields allows to overcome the “no-go” theorem for superradiant phase transitions in systems governed by the Dicke Hamiltonian

We show that the recent observation of like-charge attractions in metastable colloidal systems is naturally and quantitatively explained by the collective interactions among the surface electrons of the colloidal microspheres, predicted by QED.

We study the effect of the superfluidity of 4He of a superradiant interaction among the 4He-atoms. We show that: i) a microscopic two-fluid picture emerges; ii) the T-dependence of the roton energy Δ(T) is correctly described; iii) the p = 0 fraction of the Bose condensate is ρc 0.15; iv) the observed values of the critical velocity vcrit can be adequately understood.

Glasses are known to possess some puzzling features among condensed matter systems, as shown by the Kauzmann paradox. We show that if the coherent interaction mechanisms of Quantum Electrodynamics are taken into account, glasses are nothing but molecular liquids in which a large fraction of the molecules enter a collective, coherent state. In this conceptual framework the temperature of glass formation can be identified with the temperature at which the non-coherent fraction vanishes. Using a recently developed treatment of liquid water where QED interactions are not neglected, we suggest a possible interpretation of the surprising finding of two low-temperature water amorphs and of their phase-transition.

A recent experiment on a physical, nonbiological system of ions at room temperature has proved that microscopic ion currents can be induced by applying simultaneously two parallel magnetic fields, one rather weak static field, (-->)B(0) and one much weaker alternating field, (-->) B(ac),[B(ac) approximately 10(-3) B(0)] whose frequency coincides with the cyclotron frequency v = qB(0)/2pim of the selected ion. As a result, ionic bursts lasting up to 20 s and with amplitude up to 10 nA arise. The much larger exchanges of energy induced by thermal agitation (the "kT-problem") appear to play no role whatsoever. We have analyzed this problem in the framework of coherent quantum electrodynamics, reaching the following conclusions: (a) as has been shown in previous articles, water molecules in the liquid and solute ions are involved in their ground state in coherent ordered configurations; (b) ions are able to move without collisions among themselves in the interstices between water coherence domains; (c) because of coherence, ions can follow classical orbits in the magnetic fields. A full quantitative understanding of the experiments is thus reached.

In order to gain insight into the possible Ground State of Quantized Einstein's Gravity, we have derived a variational calculation of the energy of the quantum gravitational field in an open space, as measured by an asymptotic observer living in an asymptotically flat space-time. We find that for Quantum Gravity (QG) it is energetically favourable to perform its quantum fluctuations not upon flat space-time but around a "gas" of wormholes of mass m p, the Planck mass (m p 1019 GeV) and average distance l p, the Planck length a p(a p 10–33 cm). As a result, assuming such configuration to be a good approximation to the true Ground State of Quantum Gravity, space-time, the arena of physical reality, turns out to be well described by Wheeler's quantum foam and adequately modeled by a space-time lattice with lattice constant l p, the Planck lattice.

We derive the screen factor for the radiation flux from an optically thick plasma of electron-positron pairs and photons, created by vacuum polarization process around a black hole endowed with electromagnetic structure.

We show how an incorrect prediction of the t-dependence of diffractive deep inelastic scattering in the Anisotropic Chromo-Dynamics (ACD) framework was due to the erroneous evaluation of colour-traces through the perturbation theory prescription. By employing the “colour filtering” required by colour confinement, good agreement with experiment is obtained. As a result we extend our discussion to the diagrams of PQCD and we argue that submitting them to “colour filtering” removes their inconsistency with quark confinement and with the basic ideas of ACD.

In the framework of quantum electrodynamics (QED), the universally accepted theory of ordinary condensed matter, we analyse a system of ions dissolved in water. Contrary to the common opinion that for aqueous solutions in normal conditions, QED can be well approximated by classical physics or by the semiclassical approximations of molecular dynamics, we find for such systems QED solutions of a very different nature. Such solutions appear to solve several paradoxes that plague the conventional approaches. Our main result is that ions dissolved in water are not in a gaseous state, but settle in a coherent configuration, where they perform plasma oscillations in resonance with a coherent electromagnetic field, thus providing a satisfactory understanding of the thermodynamics of electrolytes. In this new framework, we also find a simple explanation of the phenomenon of osmosis.