Quantum Control and Quantum Information

Faculty: A. Ferrante, M. Pavon, F. Ticozzi

The key advantage in using quantum systems to store, manipulate and transmit information consists in the non-classical correlations that their states exhibit (superpositions and hence, entanglement). The Quantum Information (QI) field, since its very beginning with the Feynman's intuition about the potential of a computer based on quantum systems, has gained growing interest and consensus. Now it appears as a wide texture of intriguing applications (quantum computing, cryptography, telecommunication and control of microscopical physical systems) and theoretical challenges (e.g. developing a suitable theory that extends classical information-theoretic results to QI, modeling quantum dynamical systems and getting deeper insights in the quantum measurement description). Proof-of-principle quantum computers have been realized, proving to be potentially more efficient in attacking specific tasks. The most appealing results improve the performance of the state-of-the-art solutions to crucial problems, as prime numbers factoring and search in unsorted database (Shor's and Grover's algorithms). Quantum communication channels have been successfully tested, allowing secure information transaction and cryptography by exploiting the peculiar features of quantum correlations.

In order to exploit the peculiar features of quantum information processing for real-world applications, one needs physical support, i.e. a quantum device suitable to encode, process, store and “read-out” quantum information. Most of the tasks we need to address in order to realize a quantum computer can be reformulated in the framework of control and estimation theories, once the appropriate physical model has been provided. Clearly, the information-processing applications are not the only ones appealing to a control engineer. Controlling a physical system at its very fundamental level is a charming challenge by itself, and a compelling problem for many experimentalists.