Phase-Mediated Attractor Dynamics (PMAD) Reveals Structure in RXTE GRS 1915+105 Noise

We present a phase-space analysis of non-QPO, stochastic "noise" segments in GRS 1915+105 1-second X-ray light curves using Phase-Mediated Attractor Dynamics (PMAD). By isolating noise segments via RMS, skewness, and higher-order statistics, constructing cosine-delta sequences, and projecting onto stiff (low-variance) axes, we reveal discrete, lowdimensional attractor structure underlying flux variability. Across 49 concatenated non-contiguous light curve samples, the system collapses onto ∼3 stiff axes with blocky recurrence plot structures, interrupted by sharp gaps corresponding to basin transitions. RQA and angular Lyapunov proxies confirm strong contraction along stiff axes with short-range local determinism within basins, interrupted by sharp transitions between discrete phase states. Even in the traditionally disregarded noise sector, the black hole accretion flow exhibits robust phase-mediated organization.