February 3, 2023

Quantum measurements: gain, disturbance and reversibility

Quantum measurements: gain, disturbance and reversibility

Researchers at Korea Institute of Science and Technology (KIST) have recently tried to capture the interplay between different types of information that are important while collecting quantum measurements, namely information gain, disturbance and reversibility.

Information gain, disturbance and reversibility are three crucial quantities impacting quantum measurement procedures. The key objective of the recent work by Lee, Lim and their colleagues was to show that there is a trade-off relation between all these three quantities.

To achieve this, the team built an interferometer, an optical device that merges two or more sources of light together to create an interference pattern that can then be measured and analyzed. The interferometer they created has three optical paths and can couple photonic qutrits (i.e., units of quantum information) with path degrees of freedom.

Based on the measurements they collected, the researchers were then able to estimate three types of information content and demonstrate a complete information trade-off, by manipulating a photonic qutrit state and the strengths of quantum measurement. Their findings show that quantum measurements split the information of a quantum state into three different parts, namely the information gain, disturbance and reversibility.

The findings could have numerous important implications, as they clearly delineate the most important quantities for preserving information while collecting quantum measurements. In addition to inspiring new quantum research studies, this work could also pave the way for the development of more secure quantum information processing tools.

The paper has been published in Physical Review Letters.

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