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Search for empirical schemes to evidence non-classicality of large masses is a central quest of current research. However, a practical scheme to witness inherent non-classicality of a large mass is still lacking. To this end, based on our recent proposal, I will present a striking result: a mass-independent demonstration of non-classicality is possible for harmonic oscillator systems. In fact, our adaptation enables probing non-classicality for literally any mass, momentum, and frequency. Moreover, coarse grained position measurements at an accuracy much worse than the standard quantum limit, as well as knowing the relevant parameters only to this precision, without requiring them to be tuned, suffice for our proposal. These should drastically simplify the experimental effort in testing the nonclassicality of massive objects ranging from atomic ions to macroscopic mirrors in LIGO.
In the second part of my talk, a table-top experimental proposal to probe the non-classicality of the gravitational field will be presented. A defining signature of classical systems is their in principle measurability without disturbance: a feature manifestly violated by quantum systems due to measurement-induced collapse. I will show that this can be used to test the non-classicality of the gravitational field generated by a source-mass in quantum superposition. This test, when added to the recently proposed entanglement-witness based tests [Bose et al., Marletto-Vedral], enlarges the domain of quantum mechanical postulates being tested for gravity. Moreover, the proposed test yields a signature of quantum measurement induced disturbance for any rate of decoherence, and is device independent.
Ref: (1) Debarshi Das, Dipankar Home, Hendrik Ulbricht, Sougato Bose, arXiv:2211.10318 [quant-ph].
(2) Farhan Hanif, Debarshi Das, Jonathan Halliwell, Dipankar Home, Anupam Mazumdar, Hendrik Ulbricht, Sougato Bose, arXiv:2307.08133 [gr-qc]. |