Dynamical Exciton Condensates in Biased Electron-Hole Bilayers

Area of Science:

• Condensed Matter Physics
• Quantum Optics
• Materials Science

Background:

• Bilayer materials can host interlayer excitons, where electrons and holes reside in separate layers.
• Maintaining a nonzero exciton density typically requires a bias chemical potential, achieved through optical pumping or electrical contacts.

Purpose of the Study:

• To investigate the behavior of exciton condensates in bilayer materials when charge tunneling is present.
• To explore the implications of the ac Josephson effect on exciton condensates.
• To examine the tunability of condensate properties and their interaction with optical cavities.

Main Methods:

• Theoretical analysis of charge tunneling in bilayer systems.
• Modeling exciton condensates within the framework of the ac Josephson effect.
• Investigating the influence of optical cavities on condensate dynamics.

Main Results:

• Demonstrated that charge tunneling leads to exciton condensates entering the dynamical regime of the ac Josephson effect.
• Identified physical consequences including measurable tunneling currents.
• Showed that condensates can be tuned from bright (photon-emitting) to dark states.
• Revealed that coupling with cavity photons can lead to superradiant phases depending on the bias.

Conclusions:

• Charge tunneling is a critical factor in the dynamical behavior of exciton condensates in bilayer materials.
• The ac Josephson effect provides a framework for understanding and controlling these condensates.
• Tunability and cavity coupling offer pathways to novel quantum optical phenomena in these systems.