Extraction of information from a single quantum

TL;DR

This paper demonstrates that extracting information from a single quantum using generalized partial measurements and measurement reversal is fundamentally impossible, highlighting a key limitation in quantum tomography.

Contribution

It proves that no information can be obtained from a single quantum via this measurement scheme, challenging assumptions about quantum measurement capabilities.

Findings

No information can be extracted using the proposed scheme.

Extraction of information from single quanta conflicts with quantum principles.

Measurement reversal does not enable information gain from single quantum states.

Abstract

We investigate the possibility of performing quantum tomography on a single qubit with generalized partial measurements and the technique of measurement reversal. Using concepts from statistical decision theory, we prove that, somewhat surprisingly, no information can be obtained using this scheme. It is shown that, irrespective of the measurement technique used, extraction of information from single quanta is at odds with other general principles of quantum physics.