From Thought Experiment to Qubit: Schrödinger's Cat at Ninety
In 1935, Schrödinger introduced the cat as a reductio ad absurdum of quantum superposition. Ninety years later, “cat states” — superpositions of coherent states with opposite phases — are a practical tool in quantum computing. Bosonic cat qubits have bit-flip times exceeding minutes, scaling exponentially with photon number, and are among the leading architectures for fault-tolerant quantum computation. The cat is no longer a paradox. It is a qubit.