Part XI — Quantum Hardware
Above the hardware line — states, algorithms, codes — everything was abstraction. Here it stops: a quantum computer is a physical object built in a cleanroom or suspended in a vacuum, and every property you care about (fidelity, speed, scale) traces back to a physical mechanism and a physical limit. This part walks the real platforms: what the qubit physically is, what each design is good at, what it pays for it, and what you can actually reach from a laptop through cloud access today.