In the context of infinite-dimensional quantum systems, genuinely described by continuous variables, some novel quantum technologies (including quantum optomechanical systems, ions in micro-fabricated traps and atomic ensembles) are now reaching a level of maturity that opens up unprecedented opportunities for the processing of quantum information. A common trait of these systems is the fact that their quantum continuous variables are spatially confined, in contrast with traditional systems composed of travelling waves. This favours their scalability and therefore the possibility that they could offer to perform advanced quantum information tasks. However their spatial confinement also raises some issues related with measurement and communication, which will be the main subject of this seminar. First, I will introduce a minimal scheme to tomographically reconstruct continuous variables in the case of quantum networks composed of confined oscillators. Then, I will present a general framework to coherently convert confined into travelling continuous variables and vice versa. This scheme can be used to effectively "open" a high-Q electromagnetic resonator, that is, to release the quantum state initially prepared in it in the form of a travelling wave. I will discuss two feasible implementations of the latter model in the optical domain, based on ensembles of two-level atoms interacting with cavity fields.


Seminar, October 1, 2013, 16:00. Seminar Room

Hosted by Antonio Acín