arXiv subjects

Sagnik Ray

Publications and source records attributed to Sagnik Ray.

3 recordsLinked to original sources

arXiv2025

Maximally $\psi-$epistemic models cannot explain gambling with two qubits

We investigate the minimal proof for ruling out maximally $\psi-$epistemic interpretations of quantum theory, in which the indistinguishable nature of two quantum states is fully explained by the epistemic overlap of their corresponding distributions over ontic states. To this end, we extend the standard notion of epistemic overlap by considering a penalized distinguishability game involving two states and three possible answers, named as Quantum Gambling. In this context, using only two pure states and their equal mixture, we present an experimentally robust no-go theorem for maximally $\psi-$epistemic models, showing that qubit states achieve the maximal difference between quantum and epistemic overlaps.

quant-ph↗

arXiv2025

Communication scenario enables robust self-testing of n-party Greenberger-Horne-Zeilinger basis measurements

Entangled basis measurements play a crucial role in distributing quantum entanglement between parties across a quantum network. In this work, we adopt a semi-device-independent approach that enables the self-testing of n-qubit Greenberger-Horne-Zeilinger (GHZ) basis measurements without requiring shared entanglement between distant parties. Our method relies solely on input-output statistics from a communication scenario involving n spatially separated senders, each receiving two bits of input, and a single receiver with no input. We analyze the robustness of the proposed self-testing protocol. Additionally, we introduce a protocol for robust self-testing of the three-outcome partial Bell basis measurement that is easily implementable in an optical setup.

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arXiv2024

Failure of epistemic models to explain the antidistinguishability of quantum mixed preparations

We investigate the limits of epistemic models in reproducing the empirical predictions of general quantum preparations. This involves comparing the common quantum overlap determined by the anti-distinguishability of a set of preparations with the common epistemic overlap of the probability distribution over the ontic states describing these preparations. We show that no epistemic model with non-zero common overlap can reproduce the predictions of quantum theory for mixed preparations, even for qubit systems. We explicitly provide sets of distinct mixed preparations, starting from qutrit systems, that give rise to identical quantum mixed states for which the common epistemic overlap must be zero. Finally, we demonstrate the strongest form of preparation contextuality by presenting pairs of mixed preparations that yield identical quantum mixed states while their epistemic overlap must vanish.

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