  Conventional criticality-based quantum metrological schemes work only at zero
or very low temperature because the quantum uncertainty around the quantum
phase-transition point is generally erased by thermal fluctuations with the
increase of temperature. Such an ultralow-temperature requirement severely
restricts the development of quantum critical metrology. In this paper, we
propose a thermodynamic-criticality-enhanced quantum sensing scenario at finite
temperature. In our scheme, a qubit is employed as a quantum sensor to estimate
parameters of interest in the Dicke model which experiences a thermodynamic
phase transition. It is revealed that the thermodynamic criticality of the
Dicke model can significantly improve the sensing precision. Enriching the
scope of quantum critical metrology, our finding provides a possibility to
realize highly sensitive quantum sensing without cooling.
