Temporal Variability in Ultra-weak Photon Emission: A Time Series Analysis of Photon Count Data

Abstract

This study examined the temporal dynamics of ultra-weak photon emission (UPE) from the hands and the effect of transient blood flow restriction on emission patterns. Photon counts from dorsal and palmar surfaces were analysed using frequency distribution, Fano factor, spectral analysis, and recurrence quantification analysis. Results indicated that UPE exhibits predominantly stochastic, right-skewed distributions with variability exceeding that of a Poisson process. While Fano factor and spectral analyses provided limited evidence of persistent structure, recurrence analysis revealed occasional short-lived deterministic patterns, particularly in palmar regions. A significant decrease in photon emission (~15.8%) followed blood flow restriction, demonstrating UPE’s sensitivity to physiological changes. However, reproducibility and within-subject consistency varied widely (wsCV: 37–53%), highlighting the need for improved measurement protocols. Overall, UPE appears to be governed largely by random processes but remains responsive to acute physiological interventions, supporting its potential as a non-invasive biomarker for metabolic and vascular status.