Optical Manipulation of Bipolarons in a System with Nonlinear Electron-Phonon Coupling

Area of Science:

• Quantum mechanics
• Condensed matter physics
• Materials science

Background:

• Electron-phonon interactions are fundamental in solids, influencing material properties.
• Nonlinear coupling between electrons and phonons can lead to complex emergent phenomena.
• Controlling quantum states with external fields is crucial for quantum technologies.

Purpose of the Study:

• To investigate the quantum mechanical evolution of two electrons coupled to quantum phonons.
• To simulate the system's response to optical pulses and explore electron-electron interactions.
• To determine the conditions for inducing and controlling electron binding via optical fields.

Main Methods:

• Full quantum mechanical simulations of electron-phonon systems.
• Modeling the dynamical response to short, spatially uniform optical pulses.
• Analysis of electron-electron interaction modifications due to nonlinear coupling and external fields.

Main Results:

• Nonlinear electron-phonon coupling can dynamically alter phonon frequencies, leading to electron attraction.
• Optical pulses tuned below the phonon frequency can induce long-lived, metastable bound electron states.
• Electron-electron interactions can be switched between attractive and repulsive using sequential optical pulses of different frequencies.

Conclusions:

• Optical pulses offer a powerful method to control electron-electron interactions and induce binding.
• The observed electron binding is robust, effective even with weakly dispersive phonons and anharmonic spectra.
• This work demonstrates a pathway for quantum control of interacting electron systems in various dimensions.