Quantum Information: Entanglement, Decoherence and Chaos

Coordinators: Carlton M. Caves, David P. DiVincenzo, Ataç Imamoglu, Mark A. Srednicki, Wojciech H. Zurek

The superposition principle of quantum mechanics and the phenomenon of quantum entanglement offer the possibility of fundamentally new forms of computation, information processing, and communication. The invention of quantum algorithms for the prime factorization of large integers and for performing fast searches on databases have provided the necessary boost to transform quantum computation into a dynamic and rapidly expanding field of research, on both the theoretical and experimental sides. A major breakthrough has come with the invention of quantum error correction and fault-tolerant quantum computation, and it can be argued that a dynamic new field of quantum information science (QIS) has emerged, with both theoretical and experimental aspects. QIS is truly interdisciplinary, and it benefits from the contributions of physicists, computer scientists, mathematicians, chemists, and engineers. Several particular areas of research are of key importance to QIS:

Quantum entanglement Much theoretical research in quantum computation since 1996 has been focused on understanding the nature of quantum entanglement among different systems, the relation between entanglement, nonlocality, and the exponential speed-up provided by quantum computation. Still, fundamental problems such as quantum channel capacity and quantum computational complexity remain largely unsolved.

Decoherence It is now well appreciated that decoherence due to contact with the environment will be the ultimate obstacle in building a viable quantum computer. Understanding the details of how decoherence affects particular composite systems is essential for the ultimate success of quantum computation. As we search for truly scalable schemes, we will want to examine all the idealized assumptions that have been made, such as the Markov approach and the approximation that each qubit interactions independently with the environment.

/// Quantum chaos Simple models of environmental decoherence treat the environment as an integrable system of harmonic oscillators; a more realistic model would treat the environment as a chaotic system. Also, a quantum computer may become chaotic, in the sense that the perturbative treatment of interactions among qubits may break down. Furthermore, it is apparent that the physical systems that have been explored as candidates for quantum hardware(optical lattices, mesoscopic quantum systems, ion traps, etc.) are an excellent testing ground for our understanding of quantum chaos, and of the transition from quantum to classical physics in general.

This program will focus on the role of quantum entanglement as a resource in quantum information processing, the impacts of decoherence and chaos on its physical implementations, and the cross-fertilization of ideas between quantum chaos and QIS. The program will bring together researchers from a variety of disciplines and will be coordinated with the concurrent program on Nanoscience. The program will run from August 13 to December 20, 2001. There will be a major conference during the week of December 4 to 7, 2001. If you are interested in attending the program, please fill out the electronic application form below. The deadline for applications is January 12, 2001. Visiting scholars who wish to bring along their graduate students and/or post-docs should also fill out the affiliate nomination form.

The ITP provides office and computing facilities; it also provides living accommodations for the visiting scholars. Financial support will be available to cover the travel and local living expenses of the long term participants, with details depending on the needs of the participants and the overall availability of funds.