The main aim of quantum error correction is to reverse the perturbing influence of an uncontrollable environment. Whether such an inversion is possible or not and how it can be achieved most efficiently, depends on the physical interaction between the quantum system considered and its environment. In quantum optical systems spontaneous decay processes are frequently occurring sources of errors. Recently, a new class of error-correcting quantum codes was developed, which is capable of correcting errors arising from such spontaneous decay processes. These jump codes exploit in an optimal way information about errors which is obtained from continuous observation of the environment. Thus, with the help of suitabe quantum gates which guarantee that such a code space is not left at any time during a quantum computation, it is possible to stabilize quantum information processing units against spontaneous decay processes. Furthermore, our group also developed a new stochastic decoupling method (PAREC -- Pauli-random-error-correction). In contrast to already known deterministic decoupling methods it is capable of suppressing decoherence over long times more efficiently.
D. Geberth, O. Kern, G. Alber, and I. Jex, Eur. Phys. J. D 46, 381 (2008)
O. Kern and G. Alber, Phys. Rev. A 73, 062302 (2006)
O. Kern and G. Alber, Phys. Rev. Lett. 95, 250501 (2005)
O. Kern and G. Alber, Eur. Phys. J. D 36, 241 (2005)
O. Kern, G. Alber, and D. L. Shepelyansky, Eur. Phys. J. D 32, 153 (2005)
G. Alber, Th. Beth, Ch. Charnes, A. Delgado, M. Grassl, and M. Mussinger,
Phys. Rev. A 68, 012316 (2003)
G. Alber, A. Delgado, and M. Mussinger, Prog. Phys. 49, 901 (2001)
G. Alber, Th. Beth, Ch. Charnes, A. Delgado, M. Grassl, and M. Mussinger,
Phys.Rev. Lett. 86, 4402 (2001)
Prof. Dr. Gernot Alber
Institut für Angewandte Physik
Hochschulstraße 4a
64289 Darmstadt, Germany
+49-6151/16-20400 (fax: 20402)
gernot.alber@physik.tu-...