M. Hossein Eskandari

Design of Advanced Readout and System-on-Chip Analog Circuits for Quantum Chip

  1. Ahmad Salmanogli,
  2. Hesam Zandi,
  3. Mahdi Esmaeili Turan Poshti,
  4. M. Hossein Eskandari,
  5. Ertan Zencir,
  6. and Mohsen Akbari
In this work, we design an advanced quantum readout architecture that integrates a four qubit superconducting chip with a novel parametric amplifier ended with analog front-end circuit.
Unlike conventional approaches, this design eliminates the need for components such as Purcell filters. Instead, a Josephson Parametric Amplifier is engineered to simultaneously perform quantum-limited signal amplification and suppress qubit energy leakage. The design features a tailored gain profile across C-band, with sharp peaks (24 dB) and troughs (0 dB), enabling qubit frequencies to align with gain minima and resonator frequencies with gain maxima.
arxiv pdf

Purcell Rate Suppressing in a Novel Design of Qubit Readout Circuit

  1. Ahmad Salmanogli,
  2. Hesam Zandi,
  3. Saeed Hajihosseini,
  4. Mahdi Esmaeili,
  5. M. Hossein Eskandari,
  6. and Mohsen Akbari
The Purcell effect, a common issue in qubit-resonator systems leading to fidelity loss is studied while its suppression is achieved using a novel qubit readout circuit design. Our approach
utilizes a unique coupling architecture in which, the qubit first interacts with a filter resonator before linking to the readout resonator. This configuration enables precise control over the Purcell decay rate and ac Stark factor without impacting on measuring time. The mentioned factor is highly sensitive to the coupling strength between the readout resonator and the filter, meaning that the factor adjustment directly impacts the qubit state detection. A major advantage of this design is that tuning the resonator-filter coupling strength is relatively straightforward, offering flexibility in fine-tuning ac Stark factor.
arxiv pdf