State-Dependent Optical Flickering in the Recurrent Nova T Coronae Borealis from TESS Photometry

T Coronae Borealis (T CrB) is a symbiotic recurrent nova that is approaching its next thermonuclear eruption after a long super-active accretion state and a pre-eruption dip state. Flickering has been observed in T CrB for decades, but its amplitude in the red-optical TESS band and its dependence on accretion state have not yet been characterized using a homogeneous set of short-cadence space photometry. We analyze TESS Science Processing Operations Center light curves of T CrB obtained in Sectors 24, 25, 51, and 78. The primary measurements use the 120 s PDCSAP_FLUX products; agreement with independently detrended SAP_FLUX, 20 s products, and target-pixel checks demonstrates that the rapid signal is not created by Presearch Data Conditioning (PDC) processing or aperture contamination. After normalizing each light curve by its median flux, we remove slow sector-scale variability with a 0.5 d segment-wise smooth trend and measure the excess fractional rms variability, binned rms amplitudes, residual distributions, and power spectral densities. TESS detects millimagnitude-level stochastic variability in all four sectors. The total-light excess fractional rms values are 0.273−0.014+0.013, 0.276−0.010+0.010, 0.318−0.012+0.013, and 0.215−0.017+0.013 per cent in Sectors 24, 25, 51, and 78, respectively, equivalent to 2.96, 3.00, 3.45, and 2.33 mmag. The power spectral densities are red-noise-like, with slopes from α=−1.56±0.09 to −1.19±0.08 over 5