Giuseppe Di Pietra
Conservation laws and temporal witnesses of nonclassicality.
Rel. Arianna Montorsi, Chiara Marletto. Politecnico di Torino, Corso di laurea magistrale in Physics Of Complex Systems (Fisica Dei Sistemi Complessi), 2022

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Abstract: 
The problem of the universality of Quantum Mechanics has been debated for a long time, with some physicists in favour of it and others instead who consider Classical Physics to be more fundamental, to the extent that it is not necessary to quantise all physical systems. One of the most challenging topics emerging from this debate in contemporary physics is Quantum Gravity, whose goal is to unify the most fundamental theories known so far: General Relativity and Quantum Physics. Recently, promising laboratoryscale tests of quantum gravity effects have been proposed. They are based on the socalled “BoseMarlettoVedral effect”, which exploits entanglement generation between two masses interacting only with a gravitational field and acting as a generalised Bell’s theorem for models of mattergravity coupling. Variants of this scheme include detection of gravityinduced nonGaussianity generation in a single mass’ dynamical evolution. Here we provide a radical generalisation of this singlemass argument, removing the underlying assumption of a specific interaction model: we show that if a system M (e.g. gravity) can induce the dynamical evolution of another system Q (e.g. a mass) from a state where one of its observables is sharp to another state where a different, noncommuting observable is sharp, then M must be nonclassical provided that an additive quantity of the total system Q+M is conserved. The argument qualifies as a general temporal equivalent of the BoseMarlettoVedral effect using the formalism of quantum theory: provided the possibility of the task and the actual conservation of the additive observable, the nontrivial “rotation” of the physical system Q will automatically rule out all possible classical models for the mediator M. The equivalence between the spatial and temporal arguments clarifies the role of time in nature, expanding on the socalled temporal locality and entanglement. The result leads to new perspectives on the design of an experiment able to assess the nonclassical nature of whatever physical systems, from gravity to biological entities, suggesting new answers to fundamental questions about the universality of Quantum Physics and its compatibility with life. 

Relators:  Arianna Montorsi, Chiara Marletto 
Academic year:  2021/22 
Publication type:  Electronic 
Number of Pages:  93 
Subjects:  
Corso di laurea:  Corso di laurea magistrale in Physics Of Complex Systems (Fisica Dei Sistemi Complessi) 
Classe di laurea:  New organization > Master science > LM44  MATHEMATICAL MODELLING FOR ENGINEERING 
Ente in cotutela:  University of Oxford (REGNO UNITO) 
Aziende collaboratrici:  University of Oxford 
URI:  http://webthesis.biblio.polito.it/id/eprint/22702 
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