Feedback cooling of a one-electron oscillator

Area of Science:

• Quantum physics
• Thermodynamics
• Experimental condensed matter physics

Background:

• Quantum systems require precise temperature control for advanced experiments.
• Electronic feedback offers a potential method for cooling quantum oscillators.
• Understanding quantum thermometry is key to characterizing low-temperature systems.

Purpose of the Study:

• To demonstrate electronic feedback cooling of a one-electron oscillator.
• To investigate quantum jump thermometry for measuring oscillator temperature.
• To verify the fluctuation-dissipation theorem in a cooled quantum system.

Main Methods:

• Utilized electronic feedback to cool a one-electron oscillator from 5.2 K to 850 mK.
• Employed novel quantum jump thermometry to analyze oscillator energy distributions.
• Directly measured electron temperature and damping rate.

Main Results:

• Achieved significant cooling of the one-electron oscillator.
• Observed a Boltzmann energy distribution, confirming accurate temperature measurement.
• Confirmed the fluctuation-dissipation invariant, independent of feedback gain.
• Demonstrated a reduced linewidth due to feedback cooling.

Conclusions:

• Electronic feedback is effective for cooling quantum oscillators to low temperatures.
• Quantum jump thermometry provides accurate characterization of quantum systems.
• The observed fluctuation-dissipation invariant supports theories of noiseless feedback.
• The technique shows promise for enhancing fundamental measurements and symmetry tests.