Collisional Quantum Thermometry

Abstract

We introduce a general framework for thermometry based on collisional models, where ancillas probe the temperature of the environment through an intermediary system. This allows for the generation of correlated ancillas even if they are initially independent. Using tools from parameter estimation theory, we show through a minimal qubit model that individual ancillas can already outperform the thermal Cramer-Rao bound. In addition, due to the steady-state nature of our model, when measured collectively the ancillas always exhibit superlinear scalings of the Fisher information. This means that even collective measurements on pairs of ancillas will already lead to an advantage. As we find in our qubit model, such a feature may be particularly valuable for weak system-ancilla interactions. Our approach sets forth the notion of metrology in a sequential interactions setting, and may inspire further advances in quantum thermometry.

Tight bound on finite-resolution quantum thermometry at low temperatures

“…Outside of the steady state regime, it was found that access to the transient probe dynamics may outperform the steady-state protocols [19][20][21], that dynamical control acts as a resource [22][23][24], and that thermometry can in some cases be mapped to a phase estimation problem [25,26]. These findings have spurred further investigations into nonequilibrium thermometry [27][28][29].…”

Catalytic transformations with finite-size environments: applications to cooling and thermometry

“…Thermometry makes part of the broader field of metrology [63][64][65][66] and aims at estimating the temperature of some environment at thermal equilibrium. In particular, temperature information can be transferred to a probe that undergoes a suitable coupling with the environment [67][68][69][70][71][72][73][74][75][76][77]. We show that this information can be increased via a two-level catalyst, thereby reducing the error in the temperature estimation.…”

Nonequilibrium readiness and precision of Gaussian quantum thermometers

“…Most of the current investigations in quantum thermometry use two-level systems as thermometers [8][9][10][11], shedding light on the link between the equilibrium heat capacity of such microscopic probes and the amount of information that can be gathered on the temperature of the environment [12][13][14], introducing bounds on the irreversible entropy production of the probe [15][16][17], and clarifying the extent of the advantages resulting from finite-time interactions for both temperature discrimination and estimation [14,18]. Such investigations have ultimately opened the path to the exploration of the role played by genuine quantum features in the enhancement of the thermometric performance of two-level quantum probes [19][20][21][22][23][24][25][26][27][28][29]. However, little has been explored about the effects that the dimensionality of the quantum probe has on the features of a given thermometric protocol.…”