Dresden 2026 – scientific programme

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QI: Fachverband Quanteninformation

QI 21: Quantum Information: Concepts and Methods III

QI 21.5: Talk

Friday, March 13, 2026, 10:45–11:00, BEY/0245

Analyzing Classical vs Quantum Temporal Correlations in Discrete-Time Counting Processes — •Bita Olamaei, Pharnam Bakhshinezhad, and Giuseppe Vitagliano — Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1020 Vienna, Austria

We consider the problem of characterizing temporal sequences or outcomes arising from a quantum finite-state automaton process. This approach can be also seen as a relaxation of the original idea of Leggett and Garg of distinguishing classical from quantum temporal correlations based on macrorealist hidden-variable theories. The latter correspond essentially to automata with only one available state [1]. We focus on discrete-time counting processes and characterize the strength of temporal correlations via the probability of the "tick" event or via the Fano factor, that have been shown to have a nontrivial memory cost [2]. In particular, we look for the quantum d-state automaton model that can saturate the memory cost of the counting process, achieving either maximal probability of tick or maximal Fano factor, thereby characterizing the nature of the resource that, in particular, allows to surpass the performance of the analogous classical d-state automaton model.

[1]- C. Budroni and G. Vitagliano, Leggett-Garg macrorealism and temporal correlations, Phys. Rev. A. 107. 040101 (2023) [2]- C. Budroni, G. Vitagliano, and M. P. Woods, Ticking-clock performance enhanced by nonclassical temporal correlations, Phys. Rev. Res. 3, 033051 (2021)

Keywords: Temporal correlations; counting processes; Fano factor; memory cost; d-state automaton model