Component-Level Inverse Design of Transmon Qubits Using Neural Networks

  1. Olivia Seidel,
  2. Firas Abouzahr,
  3. Abhishek Chakraborty,
  4. Sadman Ahmed Shanto,
  5. Saikat Das,
  6. Daniel Baxter,
  7. Jonathan Asaadi,
  8. Nicola Pancotti,
  9. Haoyu Yang,
  10. Brucek Khailany,
  11. Sara Sussman,
  12. Enectali Figueroa-Feliciano,
  13. Eli M. Levenson-Falk,
  14. and Taylor L. Patti
Designing a superconducting qubit to realize specific Hamiltonian parameters typically requires iterating through a time and compute-intensive forward loop in which the designer chooses
a layout geometry, simulates it, extracts circuit parameters such as capacitances, and refines the geometry. We study the inverse version of this task using a neural-network workflow that maps target Hamiltonian parameters directly to component-level layout parameters, which we subsequently demonstrate on a planar transmon layout. During training, we pair the inverse model with a frozen forward surrogate model and evaluate the loss in Hamiltonian space rather than in layout-parameter space. In validation against a conventional EM solver, 97% of generated designs produce usable geometries, and the inverse-plus-surrogate pipeline reaches mean percent errors of 0.73% for qubit frequency and 1.58% for anharmonicity, comparable to or below the fabrication and simulation-to-measurement uncertainty expected for academic-process transmon devices of this type. A single pipeline query takes approximately 56 ms on CPU, versus approximately 2 min for a conventional EM capacitance extraction on the same hardware, a speedup of more than 2,100 times. Batching minimizes the AI model inference overhead, reducing the runtime to 0.24 ms per sample on CPU and 2.5 microseconds per sample on GPU, resulting in speedups of 5.0 x 10^5 and 4.8 x 10^7, respectively, relative to a single conventional CPU EM extraction. Our results indicate that component-level inverse design usefully extends and complements conventional EM simulation, including for small datasets on the order of 1,000 samples.

Real-Time Detection of Charge Jumps in Superconducting Qubits with a Convolutional Neural Network

  1. Daniel Gaytan-Villarreal,
  2. Peter Meiring,
  3. Daniel Baxter,
  4. Daniel Bowring,
  5. Grace Bratrud,
  6. Matteo Cremonesi,
  7. Giuseppe Di Guglielmo,
  8. Grace Wagner,
  9. and Bowen Xiao
Ionizing radiation from cosmic rays and gammas can induce discontinuous jumps in the environmental charge of superconducting qubits (charge jumps), causing correlated errors that challenge
fault-tolerant quantum computing while simultaneously providing a detection signature for quantum sensing applications. Current detection methods operate offline, introducing latency incompatible with in-the-loop qubit control. In this paper, an online detector of charge jumps for superconducting qubits, based on a dilated causal convolutional neural network (DCCNN) designed for in-the-loop deployment on the Quantum Instrumentation Control Kit (QICK) platform, is presented. The network is trained on synthetic Ramsey tomography scans generated from qubit templates measured at the Northwestern Experimental Underground Site (NEXUS) at Fermilab, and translated to FPGA firmware via hls4ml with ap_fixed⟨16,6⟩ quantization, reaching a per-inference latency of 6.19μs on the Zynq UltraScale+ RFSoC ZCU216. At this operating point the DCCNN matches the detection efficiency of the established offline χ2 algorithm (0.843±0.022 vs. 0.866±0.020 on |Δq|∈[0.1,0.5]e at matched false-positive rate), while requiring no per-qubit hyperparameter tuning. This shifts charge-jump detection from a post-hoc diagnostic to a control-loop primitive, enabling adaptive protocols that respond to radiation-induced events in situ, with applications to quantum-computing error mitigation and to the use of superconducting qubits as particle detectors.