Non-disturbance for fuzzy quantum measurements

Zhaoqi Wu, Shifang Zhang, Junde Wu

Xiao-Ming Lu, Sixia Yu, Kazuo Fujikawa +1 more

Heisenberg's uncertainty principle is quantified by error-disturbance tradeoff relations, which have been tested experimentally in various scenarios. Here we shall report various error-disturbance tradeoff relations by decomposing the measurement errors and disturbance into two different components, namely, operator bias and fuzziness. Our uncertainty relations reveal the tradeoffs between these two components of errors, and imply various conditionally valid error-tradeoff relations for the unbiased and projective measurements. We also design a quantum circuit to measure the two components of the error and disturbance.

Chunlin Chen, Gerasimos G. Rigatos, Daoyi Dong +1 more

A partial feedback control scheme with a probabilistic fuzzy estimator (PFE) is presented for the robust control of quantum systems. In this scheme, a probabilistic fuzzy simulator is trained to estimate the quantum states for feedback control of quantum systems. Usually, the estimated state is fed back to design a controller. However, when the estimated quantum state is an almost-eigenstate, a projective measurement will be triggered for the quantum system and the measurement results will be fed back to construct the controller and regulate the fuzzy estimator. This scheme is a partial feedback strategy with controlled discontinuous measurement, where the quantum measurement serves as a control tool and is helpful for driving the quantum system to a desired state tracking even in the presence of unknown disturbances and stochastic noises. An example of a two-spin-¿ system is also presented to demonstrate the proposed approach.

Paul Busch, Teiko Heinonen, PEKKA J. LAHTI

Christophe Tzara

IKE QD

We challenge the classical assumption that the past consists of fixed, determinate events. By applying the Heisenberg Uncertainty Principle and Time-Reversal Symmetry to the verification of historical data, we propose that the past exists as a probability distribution that remains "fuzzy" even after measured. We introduce the "Measurement Stacking" effect, where subsequent attempts to verify a past event amplify its inherent uncertainty. Furthermore, we argue that the act of remembering or accessing recorded data is itself a quantum interaction that re-disturbs the historical state, suggesting that as we move further back in time, the past becomes increasingly open to probabilistic interpretation.