Bath-Induced Correlations Enhance Thermometry Precision at Low Temperatures

Non-Markovian quantum thermometry

“…However, it is unfortunate to find that the QFI tends to zero in the low-temperature limit. Being consistent with the previous works [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], it means that the thermometer becomes insufficient in measuring low temperatures under the Born-Markovian approximation.…”

“…This scaling relation works well in the full-temperature regime. Such quantum-criticality enhanced QFI succeeds in solving the problem that the QFI tends to zero in the lowtemperature regime in the conventional quantum thermometry schemes [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. It is noted that our quantumcriticality enhanced thermometry is substantially different from the one in Ref.…”

“…Quantum thermometry aims to realize precisely measuring of temperature using quantum features [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. A quantum system is chosen as a thermometer and brought into thermal contact with the measured system in thermal equilibrium.…”

“…It has been explored in various platforms, including nitrogen-vacancy centers in diamond [33,34], optical nanofibres [35], cavity optomechanical system [36], and quantum dot [37]. The advantage of using quantum features in thermometry is that the enhanced precision can be achieved in certain temperature regimes due to quantum coherence [14][15][16], strong coupling [11,19], quantum correlation [27,28,36], periodic driving [23], or nonequilibrium dynamics [13,[29][30][31][32]. A challenge of almost all of the existing schemes is that their sensing errors tend to divergence with decreasing temperature [38,39], although some ways to slow down the divergence via strong coupling [11], periodic driving [23], and fi-nite measurement resolution [24,25] have been explored.…”

Collective heat capacity for quantum thermometry and quantum engine enhancements

“…One study [13] investigated similar effects but considering dephasing coupling (no energy exchange between probe and bath). In [14] the authors analyse the thermometric consequences for of collective coupling between an ensemble of harmonic oscillators and the bath. Finally, in [15], thermometry via collective spins is investigated.…”