Single atom laser in normal-superconductor quantum dots

Year: 2019

Authors: Rastelli G., Governale M.

Autors Affiliation: Univ Konstanz, Fachbereich Phys, D-78457 Constance, Germany. Univ Konstanz, Zukunftskolleg, D-78457 Constance, Germany. Victoria Univ Wellington, Sch Chem & Phys Sci, POB 600, Wellington 6140, New Zealand. Victoria Univ Wellington, MacDiarmid Inst Adv Mat & Nanotechnol, POB 600, Wellington 6140, New Zealand.

Abstract: We study a single-level quantum dot strongly coupled to a superconducting lead and tunnel coupled to a normal electrode which can exchange energy with a single-mode resonator. We show that such a system implements a single atom laser. We employ both a semiclassical treatment and a quantum master-equation approach to characterize the properties of this laser. In particular, we find that this system can be operated with efficiency approaching unity; that is, a single photon is emitted into the cavity for every Cooper pair participating in the charge current. We find also that lasing in the proposed setup is clearly identifiable in the transport properties: in the lasing state, the electrical current through the quantum dot is pinned to the maximum value achievable in this hybrid nanostructure, and hence, the onset of lasing can be detected simply by a current measurement.


Volume: 100 (8)      Pages from: 085435  to: 085435

More Information: G. R. is grateful for the warm hospitality at Victoria University of Wellington. G. R. thanks A. D. Armour for useful discussions and G. Burkard for relevant comments. G. R. and M. G. thank K. G. Steenbergen for suggested improvements to the manuscript. G. R. acknowledges partial support from the German Excellence Initiative through the Zukunftskolleg and from the Deutsche Forschungsgemeinschaft (DFG) through the collaborative research center SFB 767.
KeyWords: single atom lasing, quantum dots, quantum transport
DOI: 10.1103/PhysRevB.100.085435