Simulating Oxygen on Real Hardware

Brian N. Siegelwax
10 min readJan 9, 2024


Fire Opal vs Superstaq, Round 1

I’ve done some experimentation with quantum phase estimation (QPE). First there was Quantum Phase Estimation!, then there was Fire Opal Stands Alone, and then there was Precision Quantum Phase Estimation, all using Q-CTRL’s Fire Opal. Most recently, there was Superstaq: The Compiler of Tomorrow using Infleqtion’s Superstaq. However, I’ve been using a generic QPE circuit from the old Qiskit textbook, modified so I could scale it up and down easily. Unfortunately, I can’t link to it because IBM keeps moving stuff around and I can’t find the source anymore.

But generic QPE doesn’t tell us what we’re really capable of. It only hints as to the size of a circuit we can execute. So, what would happen if we tried to run QPE for real? Can we do anything with it at all? And, if so, how far can we push it? Along the way, we can determine which compiler can help us push further, Fire Opal or Superstaq.

To be clear, this article and its successors will not be considering the previous performance of either Fire Opal or Superstaq. The Fire Opal evaluations came first, and then I used the same generic QPE circuits to test Superstaq. That’s all done, and these are all new circuits.

Round one… fight!