Drag the transmitter and receiver, click message bits

Extra-dimension channel - 2D

Scenario

A scalar wave equation u_tt = c^2 (u_xx + u_yy) is solved in a plane whose y direction plays the role of an extra dimension; the line y = 0 is our "brane" and carries a transmitter sending Gaussian pulses (on-off keying) to a receiver. If y is compact with circumference C, the field splits into Kaluza-Klein modes with omega^2 = k^2 + (2 pi n / C)^2: pulses shorter than about C/2 reveal the extra dimension as delayed echoes (path sqrt(d^2 + C^2)) and dispersion. In an open bulk the signal leaks away and, because the Huygens principle fails in two space dimensions, pulses leave long tails. Both cause inter-symbol interference, so the bit error rate rises with bit rate. A purely illustrative model of the idea, not a claim that real extra dimensions exist. Entanglement alone cannot carry information (no-communication theorem).