Decoherence and quantum computation
The practical implementation of any quantum information protocol has to
face the problem of the unavoidable
coupling of quantum processors with their environment. Indeed, real
systems can never be perfectly isolated from the surrounding world. It
is therefore important to understand the impact of the coupling with a
noisy environment on the stability of quantum protocols. In particular,
of these protocols including realistic models of noise, promises to
give useful insights for the design and future construction of quantum
in a noisy environment
We have studied  the fidelity of quantum teleportation for the
situation in which quantum logic gates are used to provide the long
distance entanglement required in the protocol, and where the effect of
a noisy environment is modeled by means of a generalized amplitude
Our results demonstrate the effectiveness of the quantum trajectories
approach, which allows the simulation of open systems with a large
number of qubits (up to 24).
This shows that the method is suitable for modeling quantum information
protocols in realistic environments.
We have also investigated the effects of quantum noise on
the stability of a quantum algorithm simulating the quantum dynamics of
a paradigmatic model of chaos, the baker's map. As a result of this
study, the time scales for reliable quantum computation in a
dissipative environment have been found .
Fidelity of teleportation in the
presence of a dissipative environment.
 G.G. Carlo, G. Benenti and
G. Casati, Teleportation in a noisy
environment: a quantum trajectories approach, Phys. Rev. Lett. 91, 257903 (2003).
 G.G. Carlo, G. Benenti, G. Casati and C. Mejia-Monasterio, Simulating noisy quantum protocols with
quantum trajectories, Phys. Rev. A 69, 062317 (2004).