云南大学中国西南天文研究所研究团组提出利用相对论性探测器的多普勒效应检验狭义相对论的方法

Test of Special Relativity via Doppler Effect using Transrelativistic Probes

近日，云南大学中国西南天文研究所杨元培助理教授领导的研究团队提出了利用相对论性探测器的多普勒效应检验狭义相对论的方法。

“突破摄星” （Breakthrough Starshot） 是由“突破计划”（Breakthrough Initiatives）提出的太空探索项目，旨在研发能够达到相对论性速度的太空探测器，经过20年时间达到半人马座α星并向地球传回信息。目前，突破摄星项目的第一个原型机“小精灵”（Sprites）已经被发射到近地轨道，它包括3.5 cm × 3.5 cm的芯片，仅仅重达4克。由于突破摄星的探测器被设计为最终能够接近光速，因此，他们在飞行的途中可以用来研究宇宙中的天体以及检验相对论效应。杨元培所领导的研究团队提出通过引入Robertson–Mansouri–Sexl理论下的多普勒效应和光子质量不为零情况下的多普勒效应，结合探测器的成像和光谱特征，可以检验狭义相对论的时间膨胀、洛伦兹不变，以及限制光子质量。对于一个口径3.5厘米、谱分辨率1000、速度达到五分之一倍光速的探测器，利用该方法可以将相对论时间膨胀因子限制到千分之一，同时，光子质量可以限制到10^-33克。

目前该研究成果已经发表在国际天文学专业学术期刊《天体物理学杂志》（文章链接: https://iopscience.iop.org/article/10.3847/1538-4357/ab3a3d）。

 

图：相对论速度探测器中恒星HD 33688的预测光谱。黑线表示地球参考系下的原始谱线，红线表示探测器参考系下满足狭义相对论的谱线，绿线表示探测器参考系下非狭义相对论的谱线。Predicted spectra, an A-type star, HD 33688, as observed by an probe with relativistic velocity. The black curve denotes the original spectrum in Earth frame. The red curve denotes the spectrum in the probe frame for the case of special relativity. The green curve denotes the spectrum in the probe frame for the case of beyond special relativity.

      A study by the research group led by Yuanpei Yang from the South-Western Institute for Astronomy Research (SWIFAR) at Yunnan University reports some new methods to test the special relativity via Doppler effect of transrelativistic probes. The paper has been published in The Astrophysical Journal (article link: https://iopscience.iop.org/article/10.3847/1538-4357/ab3a3d).

      Breakthrough Starshot is a research project by the Breakthrough Initiatives to develop a proof-of-concept relativistic spacecraft to be capable of making the journey to the Alpha Centauri star system taking 20 years. “Sprites”, the first prototype of the Breakthrough Starshot program, has recently been launched at a low-Earth orbit. It consists of 3.5 cm × 3.5 cm chips that weigh just 4 grams each. Because the probe velocity is designed to be a good fraction of the light speed, the probe can be used to study astronomical objects and to test special relativity during the journey. The group led by Yang introduced more general Doppler effect theories, e.g., Doppler effect under Robertson–Mansouri–Sexl framework and Doppler effect with massive photons, to set up the framework of testing special relativity. They proposed some methods to test special relativity, including time dilation and Lorentz invariance, and constrain photon mass using the Doppler effect with the images and spectral features of astronomical objects as observed in the transrelativistic probes. For example, for a transrelativistic probe with velocity of 0.2c, aperture of 3.5 cm, and spectral resolution of 1000, the time dilation factor uncertainty can be constrained to 0.001. Meanwhile, the photon mass limit is set to 10^−33 g.