# Probing Quantum Memory Effects with High Resolution

## TL;DR

This paper investigates quantum memory effects in trapped ions, revealing a measurement bias in non-Markovianity measures and demonstrating applications in local quantum probing for complex systems.

## Contribution

It uncovers a fundamental bias caused by projective measurements in quantum non-Markovianity measures and explores its implications for quantum probing.

## Key findings

- Identification of a measurement bias in non-Markovianity quantification
- Demonstration of local quantum probing applications
- Potential for understanding complex quantum systems

## Abstract

Trapped atomic ions enable a precise quantification of the flow of information between internal and external degrees of freedom by employing a non-Markovianity measure [H.-P. Breuer et al., Phys. Rev. Lett. 103, 210401 (2009)]. We reveal that the nature of projective measurements in quantum mechanics leads to a fundamental, nontrivial bias in this measure. We observe and study the functional dependence of this bias to permit a demonstration of applications of local quantum probing. An extension of our approach can act as a versatile reference, relevant for understanding complex systems.