4. Hardware: Superconducting

Superconducting Qubits (Transmons)

The Players: IBM, Google, Rigetti.

The Tech: Artificial atoms made from superconducting circuits (Josephson Junctions) cooled to near absolute zero.

• Pros: Very fast gate speeds (nanoseconds). Standard microchip fabrication.
• Cons: Short coherence times (microseconds). Wiring complexity grows with size. Needs massive dilution refrigerators.