Parametric Drive of a Double Quantum Dot in a Cavity

Area of Science:

• Quantum physics
• Mesoscopic physics
• Cavity quantum electrodynamics (cQED)

Background:

• Quantum dots are crucial for quantum computing.
• Current readout methods have limitations in signal amplification.
• Understanding charge dipole interactions in cavities is key.

Purpose of the Study:

• To demonstrate parametric modulation of a double quantum dot charge dipole coupled to a cavity.
• To achieve amplified readout signals beyond conventional dispersive protocols.
• To explore applications in quantum dot qubits and probing exotic electronic states.

Main Methods:

• Parametric modulation of a double quantum dot charge dipole at cavity frequency.
• Utilizing transverse coupling for dipole radiation within the cavity.
• Tuning intracavity field phase and amplitude to achieve a π-phase shift.

Main Results:

• Achieved amplified readout signal compared to dispersive protocols.
• Observed cavity field displacement attributed to dipole radiation, not longitudinal coupling.
• Demonstrated a π-phase shift between two dipole states.
• Substantial enhancement of the signal-to-noise ratio.

Conclusions:

• Parametric modulation offers a superior readout protocol for quantum dot qubits.
• The observed phenomenon relies on transverse coupling and dipole radiation.
• This method provides a new tool for investigating mesoscopic circuits in cavities.