Manipulation of a single charge in a double quantum dot

Area of Science:

• Quantum computing
• Solid-state physics
• Electron spin manipulation

Background:

• Quantum dots are semiconductor nanostructures that can confine single electrons.
• Controlling electron states is crucial for quantum information processing.

Purpose of the Study:

• To investigate microwave-driven transitions between charge states in a tunable double quantum dot.
• To measure the coherence times of these charge states.

Main Methods:

• Utilized microwave excitation to manipulate a single electron in a double quantum dot.
• Employed local quantum point contact charge detectors for precise measurements.
• Performed charge sensing to analyze photon-induced changes in charge state occupancy.

Main Results:

• Successfully drove transitions between (1,0) and (0,1) charge states using resonant microwaves.
• Measured the energy relaxation time (T1) to be approximately 16 ns.
• Estimated the dephasing time (T*(2)) for the charge two-level system to be at least 400 ps.

Conclusions:

• Microwave excitation provides a viable method for controlling charge states in double quantum dots.
• The measured coherence times indicate potential for utilizing these systems in quantum applications.
• Further research can explore optimizing coherence for robust quantum operations.