Microwave boson sampling

中文速览

玻色采样虽被认为经典计算机难以模拟，却受限于光子难以确定性制备和高效率探测，现有实验很难扩展到大规模。论文提出改用微波光子，在超导电路中用高品质谐振器存储光子、可调超导环实现分束，用量子比特确定性制备光子并调节相位，再通过量子非破坏测量读取每个模式的光子数。结果表明，这套方案能以高保真度制备单光子甚至更复杂的量子态，快速切换光子耦合，并实现高效、可扩展的测量，所需组件基本都已在现有超导器件中得到验证。它为展示量子计算超越经典的玻色采样提供了更现实的硬件路线，也可能直接用于分子振动光谱等量子模拟。

摘要

The first post-classical computation will most probably be performed not on a universal quantum computer, but rather on a dedicated quantum hardware. A strong candidate for achieving this is represented by the task of sampling from the output distribution of linear quantum optical networks. This problem, known as boson sampling, has recently been shown to be intractable for any classical computer, but it is naturally carried out by running the corresponding experiment. However, only small scale realizations of boson sampling experiments have been demonstrated to date. Their main limitation is related to the non-deterministic state preparation and inefficient measurement step. Here, we propose an alternative setup to implement boson sampling that is based on microwave photons and not on optical photons. The certified scalability of superconducting devices indicates that this direction is promising for a large-scale implementation of boson sampling and allows for more flexible features like arbitrary state preparation and efficient photon-number measurements.

术语表

boson sampling

玻色子采样

linear optical quantum computation

线性光学量子计算

universal quantum computer

通用量子计算机

dedicated quantum hardware

专用量子硬件

linear quantum optical network

线性量子光学网络

single-photon source

单光子源

photon-number measurement

光子数测量

feed-forward

前馈

extended Church–Turing thesis (ECT thesis)

扩展 Church–Turing 论题（ECT 论题）

computational complexity

计算复杂性

two-mode squeezed state

双模压缩态

photon-added/subtracted coherent state

光子添加/光子减去相干态

vacuum squeezed state

真空压缩态

microwave photon

微波光子

superconducting device

超导器件

superconducting resonator

超导谐振器

superconducting ring coupler

超导环形耦合器

tunable beam splitter Hamiltonian

可调谐分束器哈密顿量

phase shifter

移相器

circuit quantum electrodynamics (circuit QED)

电路量子电动力学（circuit QED）

Jaynes–Cummings interaction

Jaynes–Cummings 相互作用

quantum non-demolition measurement

量子非破坏测量

Fock-state basis

Fock 态基

bosonic creation operator

玻色子产生算符

Haar measure

Haar 测度

unitary matrix

酉矩阵

beam splitter

分束器

molecular vibronic spectrum

分子振电光谱