IBM links two 120-qubit quantum processors with superconducting cables

IBM researchers have joined two of their 120-qubit Nighthawk R1 quantum processors using four 80 cm superconducting cables, installed after the chips were already in place. Quantum states moved between chips with 99% average accuracy, and cross-chip two-qubit operations reached 94.75%. The links survived three warm-cool cycles, a step towards modular quantum computers that are easier to scale.