Burton William Cody, Kennedy Colin J, Chung Woo Chang, Vadia Samarth, Chen Wenlan, Ketterle Wolfgang
Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Fakultät für Physik, Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 München, Germany.
Phys Rev Lett. 2016 Dec 30;117(27):275301. doi: 10.1103/PhysRevLett.117.275301. Epub 2016 Dec 28.
We demonstrate a new way to extend the coherence time of separated Bose-Einstein condensates that involves immersion into a superfluid bath. When both the system and the bath have similar scattering lengths, immersion in a superfluid bath cancels out inhomogeneous potentials either imposed by external fields or inherent in density fluctuations due to atomic shot noise. This effect, which we call superfluid shielding, allows for coherence lifetimes beyond the projection noise limit. We probe the coherence between separated condensates in different sites of an optical lattice by monitoring the contrast and decay of Bloch oscillations. Our technique demonstrates a new way that interactions can improve the performance of quantum devices.
我们展示了一种延长分离的玻色-爱因斯坦凝聚体相干时间的新方法，该方法涉及将其浸入超流体浴中。当系统和浴具有相似的散射长度时，浸入超流体浴会抵消由外部场施加的或由于原子散粒噪声引起的密度涨落所固有的非均匀势。我们将这种效应称为超流体屏蔽，它能使相干寿命超过投影噪声极限。我们通过监测布洛赫振荡的对比度和衰减来探测光晶格不同位置处分离凝聚体之间的相干性。我们的技术展示了一种相互作用可改善量子器件性能的新方法。
