Channel Capacity of a Vacuum Link Whose Noise Floor Is Set by the Surviving Vacuum Density

This paper examines what data rate a link can sustain when its noise floor is set by the surviving vacuum energy density rather than by receiver engineering. The calculation is performed in a frame with a finite maximum density, the neutron-branch value rho_A = 9.718e+57 kg per cubic metre, with the electron branch at 2.874e+51 kg per cubic metre for comparison. Headline results include a bounce temperature of 3.278e+22 K, a Landauer cost at that temperature of 3.137e-01 J per bit against 2.871e-21 J per bit at 300 K, a Bekenstein allowance of 1.049e+94 bits for the stated centimetre reference region, and a Margolus-Levitin rate of 2.209e+103 per second for the same region. For the stated illustrative bandwidth and coupling the vacuum floor lies far below thermal noise at room temperature, so it does not limit any present link. All numbers are computed from the stated assumptions in the accompanying script; the study is simulated and computed, not measured.