论文标题
系外行星光谱的最终限制：量子方法
Ultimate limits of exoplanet spectroscopy: a quantum approach
论文作者
论文摘要
系外行星科学的最大挑战之一是确定极性行星的大气构成，并找到暗示在另一个世界上存在生化过程的生物签名。我们试图检测到的生物标志物是氧气或甲烷等系外星大气中的气体，它们在可见光和近红外光谱中具有深度吸收特征。在这里，我们建立了确定光谱吸收线的存在或不存在的最终量子限制，这是在存在明亮的恒星源的情况下昏暗的源。我们表征了对称和非对称假设检验的框架中相关的误差指数。我们发现，基于空间弹性的结构化测量使我们能够将来自行星传来的光解散并达到最终的量子极限。如果行星具有强度$ε\ ll 1 $相对于恒星，我们表明，这种方法的表现明显优于直接光谱，从而使误差指数提高了因子$ 1/ε$。我们发现最佳测量值是干涉技术和频谱分析的组合。
One of the big challenges in exoplanet science is to determine the atmospheric makeup of extrasolar planets, and to find biosignatures that hint at the existence of biochemical processes on another world. The biomarkers we are trying to detect are gases in the exoplanet atmosphere like oxygen or methane, which have deep absorption features in the visible and near-infrared spectrum. Here we establish the ultimate quantum limit for determining the presence or absence of a spectral absorption line, for a dim source in the presence of a much brighter stellar source. We characterise the associated error exponent in both the frameworks of symmetric and asymmetric hypothesis testing. We found that a structured measurement based on spatial demultiplexing allows us to decouple the light coming from the planet and achieve the ultimate quantum limits. If the planet has intensity $ε\ll 1$ relative to the star, we show that this approach significantly outperforms direct spectroscopy yielding an improvement of the error exponent by a factor $1/ε$. We find the optimal measurement, which is a combination of interferometric techniques and spectrum analysis.
