Manthan Badbaria

In a quantum computer, a qubit is like a tightrope walker: any puff of wind and balance is lost. Errors accumulate, and the computation falls apart. Usually, they are corrected by comparing neighboring qubits, but that's like asking the tightrope walker to glance at his neighbors — extra movements and risk.

A delicate watermark on wet paper, and a fogged-up glass before your eyes. That's roughly what reading quantum states of light looks like: fragile photon patterns get distorted by losses, and detectors catch only a small fraction of the signal.