Searcharxiv⌕ Search

arXiv subjects

Sergio De Filippo

Publications and source records attributed to Sergio De Filippo.

At least 19 recordsLinked to original sources
arXiv2020

Microscopic foundation of thermodynamics, transition to classicality and regularization of gravitational-collapse singularities within Non-unitary $4$-th Derivative Gravity classically equivalent to Einstein gravity and its Newtonian limit

A detailed and updated review is given of De Filippo's Non-unitary $4$-th Derivative Gravity and its Newtonian limit, by pointing out the crucial role of non-unitarity in addressing transition to classicality and specifically localization of macroscopic bodies, microscopic foundation of the second law of thermodynamics, measurement problem; furthermore it provides a quantum field theory of gravity possibly not only renormalizable but even finite, with a cancelation mechanism analogous to supersymmetric field theories where cancelations are due to superpartners whereas here to negative energy fields. Finally this non-unitary proposal addresses the longstanding black hole information loss problem and this according to an unorthodox view at variance with the mainstream endeavors to save unitarity at the expense of changing General Relativity in vague unspecified ways. Last but not least motivations and conceptual framework are given, as the author could not present them in his first papers written in a hurry since he was aware that in a little time he would be unable to use pc keyboard or to write on paper due to the progressing of motor neuron disease.

gr-qc↗
arXiv2020

Microscopic foundations of the Second Law of Thermodynamics within Nonunitary Newtonian Gravity

The quest for a microscopic foundation of Thermodynamics is addressed within the Nonunitary Newtonian Gravity model through the study of a specific closed system, namely a three-dimensional harmonic nanocrystal. A numerical calculation of the nanocrystal von Neumann entropy as a function of time is performed, showing a sharp monotonic increase, followed by a stabilization at late times. This behavior is consistent with the emergence of a micro-canonical ensemble within the initial energy levels, signaling, in this way, the establishment of a non-unitary gravity-induced thermal equilibrium.

cond-mat.stat-mech↗
arXiv2018

Nonunitary Newtonian Gravity Makes Semiclassical Gravity Viable for All Practical Purposes

Semiclassical Gravity replaces the energy momentum tensor $T_{μν}$ with its expectation value $\langle T_{μν}\rangle$ in Einstein equations, this making the Einstein tensor $G_{μν}$ a classical variable thus avoiding the quantization of the gravitational field. Jointly with the Copenhagen interpretation of QM, Semiclassical Gravity gives rise to cases of Superluminal Communication. It is shown in a specific instance that a model of Nonunitary Newtonian Gravity avoids Superluminal Communication by decohering linear superpositions of macroscopically distinct states, namely Schrodinger's cats.

quant-ph↗
arXiv2004

Entropic localization in non-unitary Newtonian gravity

The localizing properties and the entropy production of the Newtonian limit of a nonunitary version of fourth order gravity are analyzed. It is argued that pure highly unlocalized states of the center of mass motion of macroscopic bodies rapidly evolve into unlocalized ensembles of highly localized states. The localization time and the final entropy are estimated.

quant-ph↗
arXiv2004

A class of nonunitary models of Newtonian gravity and its unicity

A class of non-Markoffian nonunitary models for Newtonian gravity is characterized as following from some rather natural hypotheses. One of such models was previously obtained as the Newtonian limit of a classically stable version of higher derivative gravity. They give rise to a mass threshold around $10^{11}$ proton masses for gravity induced localization, to a breaking of linearity and to the possible identification of thermodynamic and von Neumann entropies.

gr-qc↗
arXiv2003

Relativistic generalizations of gravity-induced localization models

Nonunitary versions of Newtonian gravity leading to wavefunction localization admit natural special-relativistic generalizations. They include the first consistent relativistic localization models. At variance with the unified model of localization and gravity, the purely localizing version requires negative energy fields, which however are less harmful than usual and can be used to build ultraviolet-finite theories.

hep-th↗
arXiv2003

Numerical simulation of nonunitary gravity-induced localization

The localization of a quantum state is numerically exhibited in a nonunitary Newtonian model for gravity. It is shown that an unlocalized state of a ball of mass just above the expected threshold of 10^11 proton masses evolves into a mixed state with vanishing coherences above some localization lengths.

quant-ph↗
arXiv2002

Nonunitary Newtonian Gravity

It is shown that the Newtonian limit of a stable realization of HD gravity leads to a sharp transition, around 10^{11} proton masses, from the wavelike properties of microscopic particles to the classical behaviour of macroscopic bodies. Besides, due to nonunitarity, a pure state is expected to evolve into a microcanonical ensamble leading to thermal equilibrium even for truly closed systems.

gr-qc↗
arXiv2002

Nonunitary Classically Stable HD Gravity

Classical instability in fourth order gravity is cured at the expense of unitarity. The appearance of hidden degrees of freedom replicating those of ordinary matter allows for ordinary thermodynamic entropy and black hole entropy to be identified with von Neumann entropy. The emergent picture gives a substantial agreement with B-H entropy and Hawking temperature.

gr-qc↗
arXiv2002

Nonunitary HD gravity classically equivalent to Einstein gravity and its Newtonian limit

Runaway solutions can be avoided in fourth order gravity by a doubling of the matter operator algebra with a symmetry constraint with respect to the exchange of observable and hidden degrees of freedom together with the change in sign of the ghost and the dilaton fields. The theory is classically equivalent to Einstein gravity, while its non-unitary Newtonian limit is shown to lead to a sharp transition, around $10^{11}$ proton masses, from the wavelike properties of microscopic particles to the classical behavior of macroscopic bodies, as well as to a trans-Planckian regularization of collapse singularities. A unified reading of ordinary and black hole entropy emerges as entanglement entropy with hidden degrees of freedom. The emergent picture gives a substantial agreement with B-H entropy and Hawking temperature.

gr-qc↗
arXiv2002

Non-unitary HD gravity classically equivalent to Einstein gravity

Runaway solutions can be avoided in fourth order gravity by a doubling of the matter operator algebra with a symmetry constraint with respect to the exchange of observable and hidden degrees of freedom together with the change in sign of the ghost and the dilaton fields. The theory is classically equivalent to Einstein gravity, while its non-unitary Newtonian limit is compatible with the wavelike properties of microscopic particles and the classical behavior of macroscopic bodies, as well as with a trans-Planckian regularization of collapse singularities. A unified reading of ordinary and black hole entropy emerges as entanglement entropy with hidden degrees of freedom.

gr-qc↗
arXiv2001

Nonrelativistic field theoretic setting for gravitational self-interactions

It is shown that a recently proposed model for the gravitational interaction in non relativistic quantum mechanics is the instantaneous action at a distance limit of a field theoretic model containing a negative energy field. It reduces to the Schroedinger-Newton theory in a suitable mean field approximation. While both the exact model and its approximation lead to estimates for localization lengths, only the former gives rise to an explicit non unitary dynamics accounting for the emergence of the classical behavior of macroscopic bodies.

gr-qc↗
arXiv2001

The Schroedinger-Newton model as N->Infinity limit of a N color model

The generalization to N colors of a recently proposed non unitary two color model for the gravitational interaction in non relativistic quantum mechanics is considered. The N->Infinity limit is proven to be equivalent to the Schroedinger-Newton model, which, though sharing localization properties with the N=2 model, cannot produce decoherence.

gr-qc↗
arXiv2001

Gravity-induced entropy in the quantum motion of a macroscopic body

It is shown that a recently proposed model for the gravitational interaction in non relativistic quantum mechanics may turn to be relevant to the derivation of the second law of thermodynamics. In particular, the spreading of the probability density of the center of mass of an isolated macroscopic body does not imply delocalization of the wave function, but on the contrary it corresponds to an entropy growth.

gr-qc↗