Imany Poolad, Lingaraju Navin B, Alshaykh Mohammed S, Leaird Daniel E, Weiner Andrew M
School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA.
Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN 47907, USA.
Sci Adv. 2020 Jul 17;6(29):eaba8066. doi: 10.1126/sciadv.aba8066. eCollection 2020 Jul.
Control over the duration of a quantum walk is critical to unlocking its full potential for quantum search and the simulation of many-body physics. Here we report quantum walks of biphoton frequency combs where the duration of the walk, or circuit depth, is tunable over a continuous range without any change to the physical footprint of the system-a feature absent from previous photonic implementations. In our platform, entangled photon pairs hop between discrete frequency modes with the coupling between these modes mediated by electro-optic modulation of the waveguide refractive index. Through control of the phase across different modes, we demonstrate a rich variety of behavior: from walks exhibiting enhanced ballistic transport or strong energy confinement, to subspaces featuring scattering centers or local traps. We also explore the role of entanglement dimensionality in the creation of energy bound states, which illustrates the potential for these walks to quantify high-dimensional entanglement.
对量子行走持续时间的控制对于充分发挥其在量子搜索和多体物理模拟方面的全部潜力至关重要。在此，我们报告了双光子频率梳的量子行走，其中行走的持续时间或电路深度可在连续范围内调谐，而系统的物理尺寸没有任何变化，这是先前光子实现方式所不具备的特征。在我们的平台中，纠缠光子对在离散频率模式之间跳跃，这些模式之间的耦合由波导折射率的电光调制介导。通过控制不同模式之间的相位，我们展示了丰富多样的行为：从表现出增强的弹道传输或强能量限制的行走，到具有散射中心或局部陷阱的子空间。我们还探讨了纠缠维度在能量束缚态创建中的作用，这说明了这些行走在量化高维纠缠方面的潜力。
