Relaxation times do not capture logical qubit dynamics

@article{Pal2022RelaxationTD,
  title={Relaxation times do not capture logical qubit dynamics},
  author={Amit Kumar Pal and Philipp Schindler and Alexander Erhard and 'Angel Rivas and Miguel A. Martin-Delgado and Rainer Blatt and Thomas Monz and M. Muller},
  journal={Quantum},
  year={2022}
}
Quantum error correction procedures have the potential to enable faithful operation of large-scale quantum computers. They protect information from environmental decoherence by storing it in logical qubits, built from ensembles of entangled physical qubits according to suitably tailored quantum error correcting encodings. To date, no generally accepted framework to characterise the behaviour of logical qubits as quantum memories has been developed. In this work, we show that generalisations of… 
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Relaxation times do not capture logical qubit dynamics.
TLDR
This work shows that generalisations of well-established figures of merit of physical qubits to logical qubits fail and do not capture dynamics of logical qu bits, and shows that a suitable set of observables, formed by code space population and logical operators within the code space, allows one to track and characterize the dynamical behaviour of logicalqubits.

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