论文标题
激光连贯的海森堡极限
The Heisenberg limit for laser coherence
论文作者
论文摘要
为了量化量子光学相干性，需要光的粒子和波形。对于理想的激光束[1,2,3]，可以将其大致认为是连续发射到光束上的光子数量相同的相。这个数字，$ \ mathfrak {c} $，可能大于$μ$，即激光器本身中的光子数量。理想激光器的$ \ mathfrak {C} $的限制被认为是$μ^2 $ [4,5]的限制。在这里，假设激光器的操作一无所知，只是它会产生一个光束，其某些属性与理想激光光束的宽度接近，并且它没有外部相干来源，我们得出了上限：$ \ mathfrak {c} = o（μ^4）$。此外，使用矩阵产品状态（MPSS）方法[6,7,8,9]，我们找到了一个实现此缩放的模型，并证明它可以原理使用电路量子量子电动力学（QED）[10]实现。因此，$ \ mathfrak {c} = o（μ^2）$只是标准量子限制（SQL）;最终的量子限制或海森堡极限在四边形上更好。
To quantify quantum optical coherence requires both the particle- and wave-natures of light. For an ideal laser beam [1,2,3], it can be thought of roughly as the number of photons emitted consecutively into the beam with the same phase. This number, $\mathfrak{C}$, can be much larger than $μ$, the number of photons in the laser itself. The limit on $\mathfrak{C}$ for an ideal laser was thought to be of order $μ^2$ [4,5]. Here, assuming nothing about the laser operation, only that it produces a beam with certain properties close to those of an ideal laser beam, and that it does not have external sources of coherence, we derive an upper bound: $\mathfrak{C} = O(μ^4)$. Moreover, using the matrix product states (MPSs) method [6,7,8,9], we find a model that achieves this scaling, and show that it could in principle be realised using circuit quantum electrodynamics (QED) [10]. Thus $\mathfrak{C} = O(μ^2)$ is only a standard quantum limit (SQL); the ultimate quantum limit, or Heisenberg limit, is quadratically better.
