Quantum Thermometry for Ultra-Low Temperatures Using Probe and Ancilla Qubit Chains

Area of Science:

• Quantum Physics
• Quantum Metrology
• Thermodynamics

Background:

• Accurate ultra-low temperature measurement is crucial for fundamental physics research and quantum technologies.
• Existing quantum thermometry techniques face limitations in range and precision at extremely low temperatures.

Purpose of the Study:

• To propose and analyze a novel quantum thermometry scheme utilizing a probe qubit coupled to ancilla qubits.
• To investigate methods for enhancing the range and precision of ultra-low temperature measurements.
• To explore the role of qubit chain interactions in quantum thermometry.

Main Methods:

• Theoretical analysis of a qubit chain model with Heisenberg XX and Dzyaloshinskii-Moriya (DM) interactions.
• Evaluation of quantum Fisher information (QFI) to characterize measurement precision limits.
• Systematic variation of ancilla qubit count and model parameters.

Main Results:

• Demonstrated control over achievable precision bounds in quantum thermometry by adjusting system parameters.
• Showcased the ability to tune the number of quantum Fisher information (QFI) peaks as a function of temperature.
• Interpreted results in terms of energy transition influences on measurement range and QFI peak behavior.

Conclusions:

• The proposed probe qubit-ancilla chain system offers a powerful and precise platform for quantum thermometry.
• System parameter and ancilla qubit number are key factors in optimizing ultra-low temperature measurements.
• This approach advances the capabilities for precise thermometry in the quantum regime.