查看更多>>摘要：A hypothetical photon mass mγcan produce a frequency-dependent vacuum dispersion of light,which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance.The dispersion measure and redshift measurements of fast radio bursts(FRBs)have been widely used to constrain the rest mass of the photon.However,all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard ACDM cosmological context.In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons,here we employ a new model-independent smoothing technique,artificial neural network(ANN),to reconstruct the Hubble parameter H(z)function from 34 cosmic-chronometer measurements.By combining observations of 32 well-localized FRBs and the H(z)function reconstructed by ANN,we obtain an upper limit of mγ≤ 3.5 × 10-51 kg,or equivalently mγ≤ 2.0 × 10-15 eV/c2(mγ ≤ 6.5 × 10-51 kg,or equivalently mγ ≤ 3.6 × 10-15 eV/c2)at the 1σ(2σ)confidence level.This is the first cosmology-independent photon mass limit derived from extragalactic sources.
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