Vacuum Rabi splitting in a semiconductor circuit QED system.

Area of Science:

• Quantum physics
• Condensed matter physics
• Materials science

Background:

• Quantum dots offer tunable electronic properties for quantum information processing.
• Strong coupling regimes are crucial for observing quantum phenomena like Vacuum Rabi splitting.
• Gallium Arsenide (GaAs) is a key material in semiconductor research.

Purpose of the Study:

• To demonstrate and characterize Vacuum Rabi splitting in a GaAs double quantum dot system.
• To investigate the strong coupling regime between a quantum dot and a resonator.
• To understand the decoherence mechanisms in the system.

Main Methods:

• Fabrication of a GaAs double quantum dot system.
• Coupling the quantum dot to a coplanar waveguide resonator.
• Experimental measurement and derivation of coupling strength (g), decoherence rate (γ), and resonator decay rate (κ).

Main Results:

• Demonstration of distinct Vacuum Rabi oscillation in the strong coupling regime.
• Quantification of system parameters: (g,γ,κ) ≈ (30, 25, 8.0) MHz.
• Interpretation of decoherence magnitude attributed to electron-piezoelectric acoustic phonon coupling.

Conclusions:

• The GaAs double quantum dot coupled to a resonator exhibits strong coupling, evidenced by Vacuum Rabi splitting.
• Electron-phonon interactions are identified as a significant source of decoherence in this system.
• The findings contribute to the development of quantum technologies using semiconductor-based qubits.