arXiv subjects

Felipe Sobrero

Publications and source records attributed to Felipe Sobrero.

5 recordsLinked to original sources

arXiv2026

From Feynman-Vernon to Wiener Stochastic Path Integral

We establish a direct connection between the Feynman-Vernon path integral formalism for open quantum systems and the Wiener path integral used in classical stochastic dynamics. By considering a generalized influence functional in the strong decoherence limit, we demonstrate that integrating over the quantum coherence length leads to a derivation of stochastic Langevin dynamics. Specifically, we show that the quantum Feynman measure transforms into the stochastic Wiener measure. Applying this framework to the Wigner function representation, we show that the system follows a stochastic path interpretable via classical probability theory. Finally, we address the inverse problem: constructing an equivalent quantum influence functional from a given classical Langevin equation.

quant-ph↗

arXiv2026

On the quantum nature of strong gravity

Belenchia et al. [Phys. Rev. D 98, 126009 (2018)] have analyzed a gedankenexperiment where two observers, Alice and Bob, attempt to communicate via superluminal signals using a superposition of massive particles dressed by Newtonian fields and a test particle as field detector. Quantum fluctuations in the particle motion and in the field prevent signaling or violations of quantum mechanics in this setup. We reformulate this thought experiment by considering gravitational waves emitted by an extended quadrupolar object as a detector for Newtonian tidal fields. We find that quantum fluctuations in the gravitational waves prevent signaling. In the Newtonian limit, rotating black holes behave as extended quadrupolar objects, as consequence of the strong equivalence principle. It follows that consistency of the Newtonian limit of general relativity with quantum mechanics requires the quantization of gravitational radiation, even when the waves originate in strong gravity sources.

gr-qc↗

arXiv2025

Scalar-tensor theories in the Lyra geometry: Invariance under local transformations of length units and the Jordan-Einstein frame conundrum

The Lyra geometry provides an interesting approach to develop purely geometrical scalar-tensor theories. Here we present a theory on Lyra manifolds which contains generalizations of both Brans-Dicke gravity and Einstein-Gauss-Bonnet scalar-tensor theory. It is shown that the symmetry group of gravitational theories on the Lyra geometry comprises not only coordinate transformations but also local transformations of length units, so that the Lyra function is a conformal factor which locally fixes the unit of length. The Lyra geometry is thus a generalization of Riemannian geometry which includes spacetime-dependent length units. By performing a Lyra transformation to a frame in which the unit of length is globally fixed, it is shown that General Relativity (GR) is obtained from the Lyra Scalar-Tensor Theory (LyST). Through the same procedure, even in the presence of matter fields, it is found that Brans-Dicke gravity and the Einstein-Gauss-Bonnet scalar-tensor theory are obtained from their Lyra counterparts. It is argued that this approach is consistent with the Mach-Dicke principle, since the strength of gravity in Brans-Dicke-Lyra is controlled by the scale function. It might be possible that any known scalar-tensor theory can be naturally geometrized by considering a particular Lyra frame, for which the scalar field is the function which locally controls the unit of length. The Jordan-Einstein frame conundrum is also assessed from the perspective of Lyra transformations, it is shown that the Lyra geometry makes explicit that the two frames are only different representations of the same theory, so that in the Einstein frame the unit of length varies locally. The Lyra formalism is then shown to be better suited for exploring scalar-tensor gravity, since in its well-defined structure the conservation of the energy-momentum tensor and geodesic motion are assured in the Einstein frame.

gr-qc↗

arXiv2025

Response of a classical mesoscopic oscillator to a two-level quantum system

We investigate the dynamics of a classical mechanical oscillator coupled to the simplest quantum system, a single qubit. Using the Feynman-Vernon influence functional formalism, we show that the qubit's influence manifests as both deterministic and stochastic forces on the oscillator. These forces are highly dependent on the qubit's initial quantum state, imprinting unique measurable signatures onto the oscillator's response. The present results provide a direct pathway to quantum state reconstruction through classical noise spectroscopy. By employing the Fisher Information Matrix, we quantify the efficacy of estimating the initial qubit state from the continuous classical record, revealing a fundamental temporal asymmetry between population and phase estimation. This framework has potential applications to mesoscopic optomechanical experiments, quantum metrology, and tabletop tests of the quantum nature of gravity.

quant-ph↗

arXiv2024

Charged spherically symmetric black holes in the Lyra geometry and a preliminary investigation on the overcharging process

This paper aims to investigate charged spherically symmetric static black holes in the Lyra geometry, in which a scale function naturally arises in the metric and affine structure of these type of manifolds. In particular, it is utilized the appropriate generalization of General Relativity, the recently proposed Lyra Scalar-Tensor Theory (LyST). The simplest generalization of Maxwell electrodynamics for Lyra manifolds is considered. It is presented an analytic solution for the line element of a Reissner-Nordstr\"om LyST generalization. It is shown that, due to the natural presence of a scale radius, it is possible to have three different extremal charges for positive or negative charge intervals. As a consequence, in natural units, the equality of the mass and charge defined on Lyra manifolds does not give rise to an extremal black hole, which allows the existence of solutions in which the charge is greater than the mass. An analysis with charged test particles indicates that a finite positive Lyra scale radius possibly allows for a violation of the weak cosmic censorship on Lyra manifolds, it is shown that an extremal black hole can be overcharged to the point that the emergence of a naked singularity becomes possible. The same behavior is observed for negative values of the Lyra radius if its absolute value is greater than four times the black hole mass. Notably, this investigation also shows that an eternal black hole can exist for any charge increase if the Lyra scale radius is sufficiently close to some critical values.

gr-qc↗