Analogue of Bose-Einstein condensation in a periodic system of Josephson junctions

Rudolf Gati, M. Albiez, Jonas Fölling +2 more

Matteo Cirillo, Vittorio Merlo, Roberto Russo +6 more

A. I. Yakimenko, Oles Matsyshyn, Artem Oliinyk +3 more

We study dynamical processes in coherently coupled atomic Bose-Einstein condensates. Josephson effects in ring-shaped and dumbbell geometries are theoretically investigated. Conditions for observation of the Josephson effect are revealed. We found that multicharged persistent current in toroidal condensate can be robust even for supersonic atomic flow. In numerical simulations the acoustic analogues of event horizon in quantized superflow were observed. These theoretical finding open perspectives for investigation of Bose Josephson junctions and quantum aspects of acoustic analogue of Hawking radiation in existing experimental setups.

Augusto Smerzi

Joseph V. Pulé

Mario Vretenar, Ben Kassenberg, Shivan Bissesar +2 more

Josephson junctions are the basis for many important fields, such as ultrafast electronics with magnetic flux quanta and superconducting quantum computing. The physical predictions of Josephson junctions are highly universal and can be observed in systems as diverse as coupled superconductors, atomic Bose-Einstein condensates, and others. We experimentally demonstrate tunable tunneling between two photon Bose-Einstein condensates by a targeted shaping of the potential landscape acting on the photons during the tunneling process. The investigated device realizes an optical analogue of a 0,π-Josephson junction, which can act as a building block for an ultrafast all-optical spin glass simulator. The potential landscape in our photon Bose-Einstein condensate Josephson junctions is realized by a combination of direct laser writing for permanent mirror nanostructuring, and heating a thermosensitive polymer for runtime fine tuning of couplings.