Efficient Accessible Bounds to the Classical Capacity of Quantum Channels

Area of Science:

• Quantum Information Science
• Quantum Communication Systems
• Information Theory

Background:

• Assessing the performance of quantum communication channels is crucial for advancing quantum technologies.
• Traditional methods like process tomography are often resource-intensive and complex.
• There is a need for efficient techniques to characterize quantum channel capacities.

Purpose of the Study:

• To develop a practical method for detecting lower bounds on the classical capacity of quantum channels.
• To reduce the experimental overhead required for quantum channel characterization.
• To provide a tool applicable to various noisy quantum channel models.

Main Methods:

• Utilizing a small number of local quantum measurements.
• Reconstructing conditional probability distributions from measurement data.
• Employing classical optimization algorithms to determine capacity bounds.

Main Results:

• Successfully demonstrated a method requiring significantly less data than full process tomography.
• The technique does not necessitate prior knowledge of the quantum channel's characteristics.
• Validated the method's effectiveness on several types of noisy quantum channels.

Conclusions:

• The proposed method offers an efficient and practical approach to bound quantum channel classical capacity.
• This technique simplifies the characterization of quantum communication systems.
• It paves the way for more accessible experimental studies in quantum information theory.