Novel Superconducting Qubit Readout
A unified picture for quantum Zeno and anti-Zeno effects
5:36 pm – 5:48 pmSince its inception in 1932 by von Neumann and its articulation in 1977 by Misra and Sudarshan, the quantum Zeno paradox has been a striking feature of quantum mechanics with foundational implications and practical applications in quantum control, error suppression, and error correction. The paradox has branched off into a variety of different interpretations, making it easy to miss the unifying features of the underlying effect. In particular, quantum Zeno effects have been studied in the context of both selective and nonselective measurements; for both pulsed and continuous interactions; for suppression and enhancement of decay (Zeno / anti-Zeno effects); and even in the absence of measurement entirely.
In this talk, we present a unified picture of these effects by examining how they all arise in the context of a driven, dephased two-level system. We emphasize that Zeno effects are tightly related to the presence of an overdamped regime, and that they involve modifying a state transition rate by scrambling information about the energy gap between those states. Our simple explanation in terms of a spectral picture of quantum state transitions helps to distill the essence of these effects and clarify directions for future study.