How long can you actually keep qubits cold if they generate heat constantly?

[Cobra]

Dilution refrigerators maintain millikelvin temperatures. But quantum systems generate heat through measurement and control. How long before they heat up and you lose coherence?

[MickFoley00]

Coherence time depends on qubit type. Superconducting qubits have microseconds to milliseconds. Photonic qubits potentially longer. Heat accumulation is real but you have time to work with

[Oscar_86]

Heat dissipation is designed into system. Refrigerator removes heat faster than system generates it. Equilibrium temperature is maintained. Like your house in winter heating balances heat loss

[BretHart88]

The problem is overhead. Heat generated by error correction dwarfs heat from qubits. As you add correction the thermal load increases. That's the scaling challenge