Thermal robustness of sensing quantum phases of matter via qubit probes

@misc{das2026thermal,
  title = {{Thermal robustness of sensing quantum phases of matter via qubit probes}},
  author = {Sambunath Das and Hari Kumar Yadalam and Mark T. Mitchison and Katarzyna Roszak},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.12964},
  eprint = {2609.12964},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.12964},
}

TY  - UNPB
TI  - Thermal robustness of sensing quantum phases of matter via qubit probes
AU  - Sambunath Das
AU  - Hari Kumar Yadalam
AU  - Mark T. Mitchison
AU  - Katarzyna Roszak
PY  - 2026
DA  - 2026/09/11
PB  - arXiv
DO  - 10.48550/arxiv.2609.12964
UR  - https://arxiv.org/abs/2609.12964
AB  - We study the effect of temperature on the ability of a qubit probe to distinguish between different phases in strongly correlated systems. Now to this end, we investigate a spin-1/2 Heisenberg XXZ chain coupled to a qubit probe via a pure dephasing interaction. At zero temperature, as reported previously, the decoherence dynamics exhibit different behavior in the gapped and gapless phases of the chain, with characteristic strong oscillations in the gapped phase and monotonic decay in the gapless phase. These oscillations decay much more slowly than expected with rising temperature in the gapped phase and their remnants are still visible at infinite temperature. In the gapless phase at low temperatures, using Luttinger liquid theory, we predict that the coherence exhibits asymptotic exponential decay in time, with the decay rate sensitive to the sign of the anisotropy parameter. We conclude that probe dynamics continue to carry information about the chain even at finite, reasonably small temperatures, positioning qubit probes as sensitive and robust detectors for quantum phases of correlated spin systems.
ER  -