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Quantum Control and Quantum Information

Quantum Control and Quantum Information
Faculty: A. Ferrante, M. Pavon, F. Ticozzi
Ph.D. students: S. Bolognani
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.



Quantum Control of Open Systems

Dynamical models of quantum controlled systems present some distinctive features: The state space is compact, the control action is bilinear, and the measurement influence the state of the system. Moreover, they are heavily affected by noise, which represent a severe obstacle towards most of the typical control tasks. We are mainly interested in exploring the various ways the environment influences the dynamics, interacts with the control and the measurement actions, and can be either suppressed or exploited as a resource.


Collaborations: C. Altafini (SISSA), S. Schirmer (Cambridge), L. Viola (Dartmouth)


Quantum Information Encoding and Protection

The distinctive features of quantum systems, most notably the possibility of preparing a system in a superposition of different states, has been proven to be a potential advantage in developing a new generation of information processing devices. Many candidate physical systems have been proposed to this aim, each one of them presenting advantages and problems. No matter which system is to be chosen, however, it shall encode a certain amount of quantum information, keep it protected from the action of noise for a sufficiently long time, and allow for decoding and measurements. We study the mathematical, device-independent structure of good quantum information representation, in the effort of developing efficient algorithms that can optimize information processing in large quantum systems.

Collaborations: L. Viola (Dartmouth)






Quantum communication systems


In collaboration with the quantum optics group (Prof. P. Villoresi), the telecommunication group at the Dept. of Information Engineering, and the astronomy group of Prof. C. Barbieri, we aim to develop new technologies for establishing an earth-space quantum communication channel, and new high efficient classical communication links by using quantum encodings.

Funding: University of Padova strategic project “Quantum Future”, Dept. of Information Engineering strategic project QUINTET.



State preparation in solid-state quantum systems

Long-time dynamics and asymptotic behavior of driven quantum dynamics in solid state systems are of key interest in the realization of a new generation of scalable quantum information processing devices.

Collaborations:  L. Viola, K. Khodjasteh (Dartmouth), P. Cappellaro (MIT)


Schroedinger bridges and their application to quantum information.

The mathematical structure of Markovian stochastic dynamics is investigated, in the effort of deriving new results of interest for the quantum information community.

Funding: University of Padova research grant CPDA080209/08: “Schroedinger Bridges for Quantum Channels: A New Approach to Information Encoding and Control Design”.






Mathematical Control Theory for Quantum System
Funding: Gnampa-Indam
Duration: 2007-2008


Control of Quantum Systems ("Controllo di Sistemi Quantistici" )

Funding: University of Padova
Duration: 2000-2002