GRCon21 - Lllama and the Lake Monster: SDR in Neutral Atom Quantum Computing

Presented by Robin Coxe at GNU Radio Conference 2021 In this talk, we will provide an overview of unique, wired SDR applications for Atom Computing Inc.’s quantum computer. Our apparatus employs a suite of lasers, magnets, and cameras to cool, trap, manipulate, and read out an array of qubits constructed from optically trapped neutral atoms. The physical processes that underpin neutral atom quantum computing would not be possible without precise, closed-loop control of the amplitudes, frequencies, and phases of electromagnetic (optical) fields. This control is mediated through the acousto-optical and electro-optical effects, whereby RF signals couple to optical fields in a highly controllable manner. These RF signals are generated by Hapyxelor, our subsystem named after a mythical Canadian lake monster, that outputs an array of arbitrary RF waveforms from ~50 MHz to 16 GHz by means of a custom RFSoC-based SDR in a MicroTCA chassis. We also monitor and provide long-term (slow) feedback to our laser sources by downmixing the optical frequency noise down to the RF regime using an optical frequency comb. Our LLLama Long-term Laser Lock subsystem uses an Ettus Research USRP N210 with UBX-40 RF daughtercard and GNU Radio to monitor and analyze these downmixed signals, and provides feedback to the laser controller modules to keep the lasers in a locked state over the course of days and weeks. https://events.gnuradio.org/event/8/