arXiv subjects

Giuseppe Di Pietra

Publications and source records attributed to Giuseppe Di Pietra.

7 recordsLinked to original sources

arXiv2026

Role of non-classicality in mediated spatial quantum correlations

The study of non-classicality is essential to understand the quantum-to-classical transition in physical systems. Recently, a witness of non-classicality has been proposed, linking the ability of a system (``the mediator") to create quantum correlations between two quantum probes with its non-classicality, intended as the existence of at least two non-commuting variables. Here, we propose a new inequality that quantitatively links the increase in quantum correlations between the probes to a function of the non-commutativity of the mediator's observables. We test the inequality for various degrees of non-classicality of the mediator, from fully quantum to fully classical. This quantum-to-classical transition is simulated via a phase-flip channel applied to the mediator, inducing an effective reduction of the non-commutativity of its variables. Our results provide a general framework for witnessing non-classicality, assessing the non-classicality of a system via its intrinsic properties, independently of the specific chosen interaction dynamics.

quant-ph↗

arXiv2025

Temporal Entanglement and Witnesses of Non-Classicality

The universality of quantum theory has been questioned ever since it was proposed. Key to this long-unsolved question is to test whether a given physical system has non-classical features. Here we connect recently proposed witnesses of non-classicality, based on information-theoretic ideas, with the theory of temporal entanglement. We provide a protocol to witness the non-classicality of a system by probing it with a qubit: we show that, assuming a general conservation law, violating temporal Bell inequalities on the qubit probe implies the non-classicality of the system under investigation. We also perform proof-of-principle experimental emulations of the proposed witness of non-classicality, using a three qubit Nuclear Magnetic Resonance quantum computer. Our result is robust, as it relies on minimal assumptions, and remarkably it can be applied in a broad range of contexts, from quantum biology to quantum gravity.

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arXiv2025

Tunable non-Markovian dynamics in a collision model: an application to coherent transport

We propose a collision model to investigate the information dynamics of a system coupled to an environment with varying degrees of non-Markovianity. We control the degree of non-Markovianity by applying a depolarising channel to a fixed and rigid reservoir of qubits. We characterise the effect of the depolarising channel and apply the model to study the coherent transport of information on a chain of three interacting qubits. We show how the system-environment coupling probability and the degree of non-Markovianity affect the process. Interestingly, in some cases a Markovian environment is preferable to reduce information loss and enhance the coherent transport.

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arXiv2024

On the Role of Locality in the Bose-Marletto-Vedral Effect

Two of us recently proposed an entanglement-based witness of non-classicality, which can be applied to testing quantum effects in gravity in what is known as the Bose-Marletto-Vedral (BMV) effect. The witness is based on this idea: if a system can create entanglement between two quantum probes by local means only, then it must be non-classical. In this note we discuss the role of locality as an assumption for the theorem supporting the witness; we also discuss other related notions of locality and comment on their mutual relations.

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arXiv2024

The Bose-Marletto-Vedral experiment with nanodiamond interferometers: an insight on entanglement detection

Recently, it has been proposed a new method [arXiv:2405.21029] to detect quantum gravity effects, based on generating gravitational entanglement between two nano-diamonds with Nitrogen-Vacancy defects, in a magnetically trapped configuration. Here we analyse in detail the proposed experimental setup, with a particular focus on implementing the detection of the gravitationally-induced entanglement using an optical readout based on measuring the position of the nano-diamonds and its complementary basis. We also summarise some of the key theoretical and experimental ideas on which this proposed scheme is based.

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arXiv2024

Temporal witnesses of non-classicality in a macroscopic biological system

Exciton transfer along a polymer is essential for many biological processes, for instance light harvesting in photosynthetic biosystems. Here we apply a new witness of non-classicality to this phenomenon, to conclude that, if an exciton can mediate the coherent quantum evolution of a photon, then the exciton is non-classical. We then propose a general qubit model for the quantum transfer of an exciton along a polymer chain, also discussing the effects of environmental decoherence. The generality of our results makes them ideal candidates to design new tests of quantum features in complex bio-molecules.

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arXiv2024

Temporal witnesses of non-classicality and conservation laws

A general entanglement-based witness of non-classicality has recently been proposed, which can be applied to testing quantum effects in gravity. This witness is based on generating entanglement between two quantum probes via a mediator. In this paper we provide a "temporal" variant of this witness, using a single quantum probe to assess the non-classicality of the mediator. Within the formalism of quantum theory, we show that if a system $M$ is capable of inducing a coherent dynamical evolution of a quantum system $Q$, in the presence of a conservation law, then $M$ must be non-classical. This argument supports witnesses of non-classicality relying on a single quantum probe, which can be applied to a number of open issues, notably in quantum gravity or quantum biology.

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