Towards Zero-Dissipation, High-Isolation Switching of RF Signals for Cryogenic Logic

We present progress towards an RF switch with negligible power dissipation such that operation on the mixing chamber of a dilution fridge causes negligible heating and with high signal isolation such that cross-talk between superconducting qubits is below detectable thresholds. As superconducting quantum computing implementations grow in complexity they require ever-more coaxial control lines that carry signals between room-temperature and cryogenic environments. To reduce the heat load, physical space, complexity, and cost of many control lines it is frequent practice to use an RF switch at the coldest stage to connect a single control line from room temperature to one of several RF ports at the coldest stage. Current implementations use either magnetic solenoids that dissipate energy sufficient to heat the experimental stage for several minutes per operation, or MEMS solutions with limited signal isolation. Our implementation achieves high isolation through mm-scale physical displacement on millisecond time scales and microjoule-scale energy dissipation. Prepared by LLNL under Contract DE-AC52-07NA27344.