Imagine that you would like to make use of the powerful information processing capability of quantum devices but you are not yet equipped to implement the necessary quantum operations. You may purchase quantum devices that come with a classical interface. However, you may not necessarily trust the manufacturer's claim on the inner-working of the devices. Even if you do, the devices may be corrupted for many reasons. An important question thus arises: what can we do through classically interacting with quantum devices that may deviate from the ideal specification?
To address this question, the researchers are developing a theory of untrusted quantum devices through this project. Such a theory would be supported by two pillars: (a) Robust self-testing of quantum states and quantum operations. That is, methods for pinning down the quantum device (its state and measurements) through classical interactions. (b) General principles for proving cryptographic properties of untrusted quantum devices.
A successful theory will identify the power and limitations of classical interactions with quantum devices. In particular, it may provide new tools for designing and analyzing the security of cryptographic protocols that rely on untrusted quantum devices. This will bring the tremendous potential of quantum information processing closer to reality. The project also serves as a training program for both undergraduate and graduate students for cutting-edge research on quantum information processing.
