Speaker
Description
Temperature estimation is crucial for characterizing samples in all natural sciences. A standard
approach is provided by probe thermometry, where a probe is brought into contact with the sample
and examined after a certain amount of time has passed. In many situations however, continuously
monitoring the probe may be preferred. Here we consider a minimal model, where the probe is provided
by a two-level system coupled to a thermal reservoir–that can be Bosonic or Fermionic. Monitoring
thermally activated transitions in real time, temperature can be estimated more and more accurately as
time passes. We consider the frequentist and Bayesian approaches to thermometry and find the Fisher
information of the probe trajectories. In an attempt to improve the sensitivity of the probe adaptive
approaches are discussed, where the energy gap of the probe may be modified, possibly depending on
the previously monitored transitions. Lastly, the impact of measurement noise (weak measurement) is
addressed, and we identify a threshold noise beyond which the precision is significantly lower compared
to the noiseless scenario.
