Temporal quantum correlations provide an intriguing way of testing quantumness at the macroscopic level, with a logical hierarchy present among the quantum correlations associated with nonmacrorealism, temporal steering, and temporal inseparability. By manipulating the dynamics of a superconducting qubit, we observe the full hierarchy of temporal quantum correlations. Moreover, we show that the rich dynamics of the temporal quantum correlations, such as sudden death or revival of temporal steering, provides a useful and unique measure for benchmarking qubits on a realistic circuit. Our work finds applications in identifying the casual structure in a quantum network, the non-Markovianity of open quantum systems, and the security bounds of quantum key distribution. As an example, we demonstrate the non-Markovianity of a single superconducting qubit on the quantum circuit.
@article{arxiv.2505.01379,
title = {Observation of Full Hierarchy of Temporal Quantum Correlations with a Superconducting Qubit},
author = {Hao-Cheng Weng and Chen-Yeh Wei and Huan-Yu Ku and Shin-Liang Chen and Yueh-Nan Chen and Chih-Sung Chuu},
journal= {arXiv preprint arXiv:2505.01379},
year = {2025}
}