Oleg Mukhanov

RSFQ All-Digital Programmable Multi-Tone Generator For Quantum Applications

  1. João Barbosa,
  2. Jack C. Brennan,
  3. Alessandro Casaburi,
  4. M. D. Hutchings,
  5. Alex Kirichenko,
  6. Oleg Mukhanov,
  7. and Martin Weides
One of the most important and topical challenges of quantum circuits is their scalability. Rapid Single Flux Quantum (RSFQ) technology is at the forefront of replacing current standard
CMOS-based control architectures for a number of applications, including quantum computing and quantum sensor arrays. By condensing the control and readout to SFQ-based on-chip devices that are directly connected to the quantum systems, it is possible to minimise the total system overhead, improving scalability and integration. In this work, we present a novel RSFQ device that generates multi tone digital signals, based on complex pulse train sequences using a Circular Shift Register (CSR) and a comb filter stage. We show that the frequency spectrum of the pulse trains is dependent on a preloaded pattern on the CSR, as well as on the delay line of the comb filter stage. By carefully selecting both the pattern and delay, the desired tones can be isolated and amplified as required. Finally, we propose architectures where this device can be implemented to control and readout arrays of quantum devices, such as qubits and single photon detectors.
arxiv pdf

Flip-Chip Packaging of Fluxonium Qubits

  1. Aaron Somoroff,
  2. Patrick Truitt,
  3. Adam Weis,
  4. Jacob Bernhardt,
  5. Daniel Yohannes,
  6. Jason Walter,
  7. Konstantin Kalashnikov,
  8. Raymond A. Mencia,
  9. Igor V. Vernik,
  10. Oleg Mukhanov,
  11. Maxim G. Vavilov,
  12. and Vladimir E. Manucharyan
The strong anharmonicity and high coherence times inherent to fluxonium superconducting circuits are beneficial for implementing quantum information processors. In addition to requiring
high-quality physical qubits, a quantum processor needs to be assembled in a manner that reduces crosstalk and decoherence. In this letter, we report work on fluxonium qubits packaged in a flip-chip architecture. Here, the fluxonium qubits are embedded in a multi-chip module (MCM), where a classical control and readout chip is bump-bonded to the quantum chip. The modular approach allows for improved connectivity between qubits and control/readout elements, and separate fabrication processes. We demonstrate that this configuration does not degrade the fluxonium qubit performance, and identify the main decoherence mechanisms to improve on the reported results.
arxiv pdf