Quantum magnetometry using two-stroke thermal machines

Abstract

The precise estimation of small parameters is a challenging problem in quantum metrology. Here, we introduce a protocol for accurately measuring weak magnetic fields using a two-level magnetometer, which is coupled to two (hot and cold) thermal baths and operated as a two-stroke quantum thermal machine. Its working substance consists of a two-level system (TLS), generated by an unknown weak magnetic field acting on a qubit, and a second TLS arising due to the application of a known strong and tunable field on another qubit. Depending on this field, the machine may either act as an engine or a refrigerator. Under feasible conditions, determining this transition point allows to reduce the relative error of the measurement of the weak unknown magnetic field by the ratio of the temperatures of the colder bath to the hotter bath.

Quantum parameter estimation in a dissipative environment

“…Ultra-sensitive parameter estimation plays an important role in both theoretical and practical researches. It has wide applications from gravitational wave detection [1,2], atom clock synchronization [3,4], to various high accuracy thermometries [5][6][7] and magnetometers [8][9][10]. Many previous studies have revealed that certain quantum resources, for example, entanglement [11][12][13][14] and quantum squeezing [15,16], can substantially improve the estimation precision and beat the shot-noise limit (standard quantum limit), which is set by the law of classical statistics.…”

Quantum Finite-Time Thermodynamics: Insight from a Single Qubit Engine

“…Another application for quantum engines is in quantum sensing and in particular, thermometry. Suggestions that are based on the transition point between a quantum engine cycle and a refrigerator have recently been proposed [ 154 , 155 , 156 , 157 ].…”

Quantum thermodynamics and quantum coherence engines

“…Further significance of quantum coherent information fuel molecules can be expected in quantum sensing and metrology [197][198][199][200][201]. Using QHEs for thermometry [202] and magnetometry [203] has been proposed. Other potential impact of quantum fuels can be envisioned in the fields of quantum batteries [204,205], and thermal quantum annealing [205][206][207] or error correction [115].…”