Inducing nonclassical lasing via periodic drivings in circuit quantum electrodynamics

Area of Science:

• Quantum optics
• Superconducting circuits
• Cavity quantum electrodynamics (CQED)

Background:

• Superconducting qubits coupled to microwave cavities are key components in quantum computing.
• Engineering dissipation into quantum systems can lead to novel phenomena and functionalities.

Purpose of the Study:

• To demonstrate a single-atom laser architecture using superconducting qubits.
• To generate nonclassical light states, specifically squeezed states, from a dissipative quantum system.

Main Methods:

• Utilizing a pair of superconducting qubits coupled to a microwave cavity.
• Employing periodic modulations of qubit energy to dress the qubit-field coupling.
• Leveraging radiative decay of one qubit as an effective pumping mechanism.
• Using an auxiliary qubit to shape cavity decay for squeezed-state lasing.

Main Results:

• Successfully engineered a single-atom laser emitting nonclassical light.
• Demonstrated that dissipation can be harnessed as an effective pumping mechanism.
• Achieved lasing in a squeezed basis of the cavity mode through auxiliary qubit control.
• Characterized the system's behavior using both mean-field theory and exact calculations.

Conclusions:

• The proposed scheme effectively engineers a dissipative quantum system to function as a single-atom laser.
• The method allows for the generation of nonclassical states and may be applicable to studying quantum phase transitions.
• This work opens avenues for generating squeezing and entanglement in circuit QED architectures.