Shake before Use: Universal Enhancement of Quantum Thermometry by Unitary Driving

Area of Science:

• Quantum physics
• Quantum metrology
• Thermodynamics

Background:

• Standard quantum thermometry uses equilibrium states, limiting precision and temperature range.
• Existing nonequilibrium methods are often model-specific or lack generality.

Purpose of the Study:

• To establish a general, model-independent method for enhancing quantum thermometry precision.
• To demonstrate that unitary driving can universally boost quantum Fisher information.

Main Methods:

• Applying temperature-dependent unitary driving to a thermalized quantum probe.
• Analytically deriving the quantum Fisher information gain using information currents.
• Benchmarking results on a driven spin-1/2 thermometer model.

Main Results:

• Any temperature-dependent unitary driving enhances quantum Fisher information beyond equilibrium values.
• Information gain is quantified by a kernel of information currents.
• Resonant modulations restore quadratic-in-time scaling and enable tunable sensitivity.

Conclusions:

• Nonequilibrium unitary driving offers a universal enhancement for quantum thermometry.
• This approach overcomes limitations of standard equilibrium methods.
• The method provides a pathway for more sensitive and broadly applicable quantum thermometers.