Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA.
Institute for Theoretical Physics III, University of Stuttgart, 70550 Stuttgart, Germany.
Phys Rev Lett. 2015 Sep 18;115(12):123601. doi: 10.1103/PhysRevLett.115.123601. Epub 2015 Sep 16.
We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasibound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wave function resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.
我们展示了两个通过电磁感应透明耦合到里德堡态的光子可以通过有效库仑势相互作用。这种相互作用产生了连续的双体束缚态。在连续体中，类似于通过势垒隧穿的类束缚态，稳定束缚态可以区分出来。我们发现了多个稳定束缚态分支，其能谱由库仑势决定，从而获得了类似于氢原子的光子模拟。在某些条件下，波函数类似于双极化激元之间存在有限“键长”的双原子分子。这些状态在介质中以负群速度传播，允许进行简单的制备和检测方案，然后再缓慢衰减为一对束缚的里德堡原子。
