  A scheme for improving the sensitivity of quantum thermometry is proposed
where the sensing quantum system used to recover the temperature of an external
bath is dynamically coupled with an external ancilla (a meter) via a
Hamiltonian term $\hat{H}_I$. At variance with previous approaches, our scheme
relies neither on the presence of initial entanglement between the sensor and
the meter, nor on the possibility of performing joint measurements on the two
systems. The advantages we report arise from the fact that the presence of
$\hat{H}_I$ interferes with the bath-sensor interaction, transforming the
sensor into an effective transducer which extracts the intrinsically incoherent
information on the bath temperature, and maps it into coherences in the meter
where it can finally be recovered by local measurements.
