Debarshi Das

Quantum mechanical violation of macrorealism for large spin and its robustness against coarse-grained measurements

For multilevel spin systems, robustness of the quantum mechanical (QM) violation of macrorealism (MR) with respect to coarse-grained measurements is investigated using three different necessary conditions of MR, namely, the Leggett-Garg inequality (LGI), Wigners form of the Leggett-Garg inequality (WLGI), and the condition of no-signaling in time (NSIT). It is shown that for dichotomic sharp measurements, in the asymptotic limit of spin, the algebraic maxima of the QM violations of all these three necessary conditions of MR are attained. Importantly, the QM violations of all these persist in that limit even for arbitrary unsharp measurements, i.e., for any nonzero value of the sharpness parameter characterizing the degree of fuzziness of the relevant measurements. We also find that, when different measurement outcomes are clubbed into two groups for the sake of dichotomizing the outcomes, the asymmetry or symmetry in the number of outcomes in the two groups, signifying the degree of coarse graining of measurements, has a crucial role in discerning quantum violation of MR. The results clearly demonstrate that classicality does not emerge in the asymptotic limit of spin, whatever be the unsharpness and degree of coarse graining of the measurements.

Operational nonclassicality of local multipartite correlations in the limited-dimensional simulation scenario

For a bipartite local quantum correlation, superlocality refers to the requirement for a larger dimension of the random variable in the classical simulation protocol than that of the quantum states that generate the correlations. In this work, we consider the classical simulation of local tripartite quantum correlations

Bipartite qutrit local realist inequalities and the robustness of their quantum mechanical violation

P

Testing local-realism and macro-realism under generalized dichotomic measurements

among three parties

Characterization of the quantumness of unsteerable tripartite correlations

A, B

Einstein-Podolsky-Rosen steering cost in the context of extremal boxes

and

Sharing of tripartite nonlocality by multiple observers measuring sequentially at one side

C

Absolute Destruction of Nonlocal Resources

. If at least one of the bipartitions

Detecting Einstein-Podolsky-Rosen steering through entanglement detection

(A|BC)

Role of maximally entangled states in the context of linear steering inequalities

,