Ghafari Farzad, Tischler Nora, Di Franco Carlo, Thompson Jayne, Gu Mile, Pryde Geoff J
Centre for Quantum Dynamics, Griffith University, Brisbane, QLD, 4111, Australia.
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639673, Singapore.
Nat Commun. 2019 Apr 9;10(1):1630. doi: 10.1038/s41467-019-08951-2.
Simulations of stochastic processes play an important role in the quantitative sciences, enabling the characterisation of complex systems. Recent work has established a quantum advantage in stochastic simulation, leading to quantum devices that execute a simulation using less memory than possible by classical means. To realise this advantage it is essential that the memory register remains coherent, and coherently interacts with the processor, allowing the simulator to operate over many time steps. Here we report a multi-time-step experimental simulation of a stochastic process using less memory than the classical limit. A key feature of the photonic quantum information processor is that it creates a quantum superposition of all possible future trajectories that the system can evolve into. This superposition allows us to introduce, and demonstrate, the idea of comparing statistical futures of two classical processes via quantum interference. We demonstrate interference of two 16-dimensional quantum states, representing statistical futures of our process, with a visibility of 0.96 ± 0.02.
随机过程的模拟在定量科学中发挥着重要作用，能够对复杂系统进行表征。最近的研究在随机模拟中确立了量子优势，从而产生了一些量子设备，这些设备执行模拟时所需的内存比经典方法所能达到的更少。为了实现这一优势，内存寄存器保持相干并与处理器进行相干交互至关重要，这使得模拟器能够在多个时间步长上运行。在此，我们报告了一个随机过程的多时间步实验模拟，其使用的内存比经典极限更少。光子量子信息处理器的一个关键特性是，它能创建系统可能演变成的所有未来轨迹的量子叠加。这种叠加使我们能够引入并证明通过量子干涉比较两个经典过程的统计未来这一概念。我们展示了两个16维量子态的干涉，它们代表了我们过程的统计未来，可见度为0.96±0.02。
