English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

The questions we raise in this letter are as follows: What is the mostgeneral representation of a quantum state at a single point in time? Can weadapt the current formalisms to situations where the order of quantumoperations is coherently or incoherently superposed? If so, what are therelations between the state at a given time and the uncertainty in the order ofevents before and after it? Establishing the relationship between two-statevector formalism and pseudo-density operators, we introduce the notion of asingle-time pseudo-state. The tomographic construction of single-timepseudo-states is possible by ideal or weak measurements. We demonstrate thatthe eigenspectrum obtained from weak measurements enables us to discriminatebetween some coherent and incoherent superpositions of causal orders in pre-and post-selected systems before the process is completed. Finally, we discusssome possible experimental realizations in existing photonic setups.

Witnessing superpositions of causal orders before the process is completed