Optimal control of quantum rings by terahertz laser pulses

Area of Science:

• Quantum physics
• Semiconductor spintronics
• Quantum computing

Background:

• Precise control of single-electron states is crucial for developing quantum computing technologies.
• Semiconductor quantum rings offer a promising platform for manipulating electron spins.

Purpose of the Study:

• To establish complete control of single-electron states in a two-dimensional semiconductor quantum-ring model.
• To develop a scheme for coherent laser-driven single-gate qubits.

Main Methods:

• Utilizing optimal-control theory for laser pulses with two-component polarization.
• Investigating the manipulation of a two-level subsystem using current-carrying states in a quantum ring.

Main Results:

• Demonstrated superior control over target-state occupations compared to conventional methods.
• Achieved precise control of single-electron states in the quantum-ring model.
• Identified current-carrying states as a means to manipulate a central two-level subsystem.

Conclusions:

• A realistic approach for constructing laser-driven single-gate qubits is proposed.
• The developed control scheme offers enhanced performance over traditional Rabi oscillation methods.
• The proposed qubits exhibit switching times in the terahertz regime, enabling ultrafast quantum operations.