Controlling the uncontrollable: Quantum control of open-system dynamics

Area of Science:

• Quantum Physics
• Quantum Information Science
• Thermodynamics

Background:

• Controlling open quantum systems is crucial for quantum technologies.
• Existing methods often neglect the impact of control drives on system-environment interactions.

Purpose of the Study:

• To develop a thermodynamically consistent framework for open quantum system control.
• To incorporate control-dependent dissipation into dynamical equations.
• To demonstrate control over quantum gates and state transformations.

Main Methods:

• Developed a theoretical framework incorporating drive-modified system-environment interactions.
• Incorporated control-dependent dissipation into quantum dynamical equations.
• Analyzed entropy-changing state-to-state transformations (heating/cooling).
• Demonstrated control of nonunitary and unitary quantum gates.

Main Results:

• Established a key relation for open-system control via control-dependent dissipation.
• Achieved control over entropy-changing transformations.
• Successfully controlled nonunitary reset maps with complete memory loss.
• Identified a mechanism for controlling unitary gates by entropy removal.
• Demonstrated a universal set of single- and double-qubit unitary gates under dissipation.

Conclusions:

• The developed framework provides a robust method for controlling open quantum systems.
• Control-dependent dissipation is a key element for effective open-system control.
• This work advances the realization of quantum computation and information processing under realistic dissipative conditions.