Quantum Tomography Protocols with Positivity are Compressed Sensing Protocols

Understand

Characterizing complex quantum systems is a vital task in quantum information science.

• Quantum tomography, the standard tool used for this purpose, uses a well-designed measurement record to reconstruct quantum states and processes.
• It is, however, notoriously inefficient.
• Recently, the classical signal reconstruction technique known as "compressed sensing" has been ported to quantum information science to overcome this challenge: accurate tomography can be achieved with substantially fewer measurement settings, thereby greatly enhancing the efficiency of quantum tomography.