Orion Martin

I'll be commenting on the PR as well, but I'd like to highlight here that I agree with @daxfohl on item (2). A `CircuitOperation` combines a `FrozenCircuit` with the mappings...

@tanujkhattar for comments re: transformers.

Child of #3235

If we do this post-1.0 it needs to be an opt-in feature, but otherwise I think after is reasonable.

We have a simple comparison of qsim vs. the Cirq simulator in the [tutorial doc](https://github.com/quantumlib/qsim/blob/master/docs/tutorials/qsimcirq.ipynb), but I imagine this issue is looking towards a more complete benchmark.

@Gopal-Dahale, can you confirm that you set up both cuQuantum and NVCC on your device before building qsim? The error you are seeing occurs when the `qsim_custatevec` is not initialized,...

We have a tutorial for using GPU acceleration on GCP here: [GPU-based quantum simulation on Google Cloud](https://quantumai.google/qsim/tutorials/gcp_gpu). If you have your own GPU-enabled device that you'd like to use instead,...

Complicating factors identified for implementing option (2) described in the first comment: - CUDA must be installed on the runner **and** be exposed to the cibuildwheel Docker container. Since the...

CC @vcatherine @tpdownes

Bump for review.