Hong-Ou-Mandel interference of two phonons in trapped ions
Hong-Ou-Mandel interference of two phonons in trapped ions
复制标题
DOI：
10.1038/nature15735
复制
发表时间：
2015-11-05
期刊：
影响因子：
64.8
通讯作者：
Urabe, Shinji
中科院分区：
文献类型：
--
作者：
Toyoda, Kenji;Hiji, Ryoto;Urabe, Shinji
玻色子和费米子的量子统计以两个不可区分的粒子以量子力学方式干涉的方式表现出来。当两个玻色子粒子进入分束器时，每个输入端口都有一个光子，它们会在两个输出端口中的任何一个聚集在一起。符合计数的相应消失是Hong-Ou-Mandel效应(1)。在这里，我们展示了在囚禁离子声子系统中这种效应的声子对应，囚禁离子声子系统是通过量子化服从玻色-爱因斯坦统计的振动运动得到的集体激发。我们利用离子间的相互库仑排斥实现了声子的分束器变换，并利用这种变换进行了双声子量子干涉实验。我们观察到两个离子位置之间的声子重合几乎完全消失，证实了声子可以被认为是不可区分的玻色子粒子。这里展示的两粒子干涉纯粹是一种量子效应，没有经典的对应物，因此在此基础上应该可以证明纠缠的存在。假设在充分考虑分析脉冲的保真度的情况下，成功地产生了纠缠声子态，我们尝试在符合时间分布中产生Hong-Ou-Mandel凹陷中心的声子纠缠态。这里演示的双声子干涉证明了囚禁离子系统中声子的玻色子性质。它为建立声子模作为量子信息的载体开辟了道路(2-4)，并可能对玻色子粒子的量子模拟(5，6)和通过玻色子采样的模拟量子计算(7)有意义。
The quantum statistics of bosons and fermions manifest themselves in the manner in which two indistinguishable particles interfere quantum mechanically. When two photons, which are bosonic particles, enter a beam-splitter with one photon in each input port, they bunch together at either of the two output ports. The corresponding disappearance of the coincidence count is the Hong-Ou-Mandel effect(1). Here we show the phonon counterpart of this effect in a system of trapped-ion phonons, which are collective excitations derived by quantizing vibrational motions that obey Bose-Einstein statistics. We realize a beam-splitter transformation of the phonons by employing the mutual Coulomb repulsion between ions, and perform a two-phonon quantum interference experiment using that transformation. We observe an almost perfect disappearance of the phonon coincidence between two ion sites, confirming that phonons can be considered indistinguishable bosonic particles. The two-particle interference demonstrated here is purely a quantum effect, without a classical counterpart, hence it should be possible to demonstrate the existence of entanglement on this basis. We attempt to generate an entangled state of phonons at the centre of the Hong-Ou-Mandel dip in the coincidence temporal profile, under the assumption that the entangled phonon state is successfully generated if the fidelity of the analysis pulses is taken into account adequately. Two-phonon interference, as demonstrated here, proves the bosonic nature of phonons in a trapped-ion system. It opens the way to establishing phonon modes as carriers of quantum information in their own right(2-4), and could have implications for the quantum simulation of bosonic particles(5,6) and analogue quantum computation via boson sampling(7).