Details

Autor(en) / Beteiligte

• Souquet, J. -R.
• Woolley, M. J.
• Gabelli, J.
• Simon, P.
• Clerk, A. A.

Titel

Photon-assisted tunnelling with nonclassical light

Ist Teil von

• Nature communications, 2014-11, Vol.5 (1), p.5562-5562, Article 5562

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2014

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• Among the most exciting recent advances in the field of superconducting quantum circuits is the ability to coherently couple microwave photons in low-loss cavities to quantum electronic conductors. These hybrid quantum systems hold great promise for quantum information-processing applications; even more strikingly, they enable exploration of new physical regimes. Here we study theoretically the new physics emerging when a quantum electronic conductor is exposed to nonclassical microwaves (for example, squeezed states, Fock states). We study this interplay in the experimentally relevant situation where a superconducting microwave cavity is coupled to a conductor in the tunnelling regime. We find that the conductor acts as a nontrivial probe of the microwave state: the emission and absorption of photons by the conductor is characterized by a nonpositive definite quasi-probability distribution, which is related to the Glauber–Sudarshan P -function of quantum optics. These negative quasi-probabilities have a direct influence on the conductance of the conductor. Coherently coupling microwave photons to quantum electronic conductors could provide a useful platform for quantum information processing. Souquet et al . now theoretically demonstrate that such systems can also act as sensitive probes of the quantum properties of non-classical microwave radiation.