Dynamical monitoring in higher dimensions and the emergence of physical realism




Center for Theoretical Physics, PAS

March 29, 2023 2:30 PM

Place: Room 203, Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland

Zoom link: https://us06web.zoom.us/j/84427806931?pwd=ODBjZkNCUW94VUhCREFxbjRSeDBFdz09

Meeting ID: 844 2780 6931

Access code: nisq


To better understand the emergence of physical reality in quantum systems during the measurement procedure, we need a model that can interpolate between weak measurements and strong (projective) measurements in systems of any dimension. Although the quantum logic gates to perform that on qubits are known [e.g., A. Touil et al., PRL 128, 010401 (2022)], the question remains open regarding general qudits. Using Heisenberg-Weyl operators, we explicitly find a unitary operator acting on qudits that can be adjusted to interpolate between weak and strong (projective) non-selective measurement regimes, resulting in the monitoring map [P. Dieguez et al., PRA 97, 022107 (2018)].  Surprisingly, within our model, we found out that to get complete information of a higher dimensional system (dimension >= 5), it is not sufficient to interact it with only one qudit of the same dimension. It is necessary to employ a bigger environment to obtain a strong regime. On the other side, weak non-selective measurements can be done with a smaller environment for any dimension. We hope that our research furnishes tools for developments in the foundations of quantum mechanics, but also in quantum metrology.