Lamb-shift enhancement and detection in strongly driven superconducting circuits

Area of Science:

• Quantum optics
• Solid-state physics
• Circuit quantum electrodynamics

Background:

• The Lamb shift is a fundamental quantum electrodynamics effect.
• Broadband reservoirs are characteristic of solid-state quantum devices.
• Understanding environmental interactions is crucial for quantum system control.

Purpose of the Study:

• To investigate the enhancement of the Lamb shift in quantum systems under strong driving.
• To explore the tunability of environmental vacuum fluctuation effects.
• To propose experimental schemes for measuring the Lamb shift in superconducting circuits.

Main Methods:

• Theoretical analysis of a driven quantum system coupled to broadband reservoirs.
• Investigation of the impact of varying drive parameters.
• Focus on superconducting circuits, specifically Cooper pair boxes.

Main Results:

• Strong driving substantially enhances the Lamb shift.
• Environmental vacuum fluctuations can be distinctly tuned by adjusting drive parameters.
• The Lamb shift can be detected via shifted dressed transition frequencies or pumped charge currents.

Conclusions:

• Strong driving offers a powerful method to enhance and control the Lamb shift in solid-state quantum systems.
• Experimentally feasible measurement schemes are proposed for superconducting circuits.
• This work provides insights into the interaction of quantum systems with their environment.