Hou, JunpengLuo, Xi-WangSun, KueiBersano, ThomasGokhroo, VandnaMossman, SeanEngels, PeterZhang, Chuanwei2019-05-032019-05-032018-03-230031-9007https://hdl.handle.net/10735.1/6445The Josephson effect is a prominent phenomenon of quantum supercurrents that has been widely studied in superconductors and superfluids. Typical Josephson junctions consist of two real-space superconductors (superfluids) coupled through a weak tunneling barrier. Here we propose a momentum-space Josephson junction in a spin-orbit coupled Bose-Einstein condensate, where states with two different momenta are coupled through Raman-assisted tunneling. We show that Josephson currents can be induced not only by applying the equivalent of "voltages," but also by tuning tunneling phases. Such tunneling-phase-driven Josephson junctions in momentum space are characterized through both full mean field analysis and a concise two-level model, demonstrating the important role of interactions between atoms. Our scheme provides a platform for experimentally realizing momentum-space Josephson junctions and exploring their applications in quantum-mechanical circuits.en©2018 American Physical SocietyBose-einstein condensationSuperfluidityOscillationsGasesPhysicsJosephson effectarticleHou, Junpeng, Xi-Wang Luo, Kuei Sun, Thomas Bersano, et al. 2018. "Momentum-space Josephson effects." Physical Review Letters 120(12): 120401:1-6, doi:10.1103/PhysRevLett.120.12040112012