arXiv subjects

Ivo P. Degiovanni

Publications and source records attributed to Ivo P. Degiovanni.

5 recordsLinked to original sources

arXiv2024

QKD protected fiber-based infrastructure for time dissemination

In this study, we demonstrate the possibility to protect, with Quantum Key Distribution (QKD), a critical infrastructure as the fiber-based one used for time and frequency (TF) dissemination service. The proposed technique allows to disseminate secure and precise TF signals between two fiber-opticconnected locations, on a critical infrastructure, using both QKD and White Rabbit technique. This secure exchange allows the secret sharing of time information between two parties for the synchronization of distant clocks with the highest stability and traceable to the Italian time scale. When encrypted, time signals would reveal to a third party no useful information about the synchronization status, providing a time stability two orders of magnitude worsened.

quant-ph↗

arXiv2019

Anomalous values, Fisher information, and contextuality, in generalized quantum measurements

Postselection following weak measurements has long been investigated for its peculiar manifestation of quantum signatures. In particular, the postselected events can give rise to anomalous values lying outside the spectrum of the measured quantity, and may provide enhanced Fisher information. Furthermore, the Pusey inequality highlights that, for extremely weak measurements, non-contextual models can account for the outcome probabilities. It is then interesting to investigate whether these are linked in a unified framework. Here we discuss on the existence of a possible connection in the case of qubits. We show that when performing generic postselected measurements there exist no one-to-one mapping between them, an instance that leads to drawing more involved considerations.

quant-ph↗

arXiv2014

Quantifying the source of enhancement in experimental continuous variable quantum illumination

A quantum illumination protocol exploits correlated light beams to enhance the probability of detection of a partially reflecting object lying in a very noisy background. Recently a simple photon-number-detection based implementation of a quantum illumination-like scheme has been provided in [Lopaeva {\it et al,}, Phys. Rev. Lett. {\bf 101}, 153603 (2013)] where the enhancement is preserved despite the loss of non-classicality. In the present paper we investigate the source for quantum advantage in that realization. We introduce an effective two-mode description of the light sources and analyze the mutual information as quantifier of total correlations in the effective two-mode picture. In the relevant regime of a highly thermalized background, we find that the improvement in the signal-to-noise ratio achieved by the entangled sources over the unentangled thermal ones amounts exactly to the ratio of the effective mutual informations of the corresponding sources. More precisely, both quantities tend to a common limit specified by the squared ratio of the respective cross-correlations. A thorough analysis of the experimental data confirms this theoretical result.

quant-ph↗

arXiv2012

Quantum characterization of superconducting photon counters

We address the quantum characterization of photon counters based on transition-edge sensors (TESs) and present the first experimental tomography of the positive operator-valued measure (POVM) of a TES. We provide the reliable tomographic reconstruction of the POVM elements up to 11 detected photons and M=100 incoming photons, demonstrating that it is a linear detector.

quant-ph↗

arXiv2007

Intensity correlations, entanglement properties and ghost imaging in multimode thermal-seeded parametric downconversion: Theory

We address parametric-downconversion seeded by multimode pseudo-thermal fields. We show that this process may be used to generate multimode pairwise correlated states with entanglement properties that can be tuned by controlling the seed intensities. Multimode pseudo-thermal fields seeded parametric-downconversion represents a novel source of correlated states, which allows one to explore the classical-quantum transition in pairwise correlations and to realize ghost imaging and ghost diffraction in regimes not yet explored by experiments.

quant-ph↗