Thermal noise as a window into the quantum vacuum: Spatial patterns revealed by simple experiments

We show that the spatial structure of electromagnetic vacuum fluctuations, predicted by quantum electrodynamics, can be indirectly observed using thermal noise at radio frequencies. Using simple laboratory equipment like coaxial cables and radio frequency splitters, we detect a clear suppression of thermal noise near conducting boundaries, mirroring the expected modulation of vacuum modes. This provides accessible, experimental evidence for quantum vacuum behavior without requiring advanced optics or cryogenics.