tenpy and Yao libraries support?

[mavzolej]

Feature details

I'm wondering if there are plans for adding support for tenpy tensor network library (it's similar to quimb and sometimes outperforms it) and/or for julia Yao library (Krylov-based simulation of quantum circuits)?

Implementation

Note that tenpy TN simulation is supported in the current version of qiskit. For Yao one would just need to use some wrapper like pycall.

How important would you say this feature is?

1: Not important. Would be nice to have.

Additional information

No response

[CatalinaAlbornoz]

Hi @mavzolej, thanks for the enhancement request! Was there a specific feature within tenpy and Yao that you were looking to use?
We currently don't have tenpy or Yao integrations in our roadmap but we'd love to hear more about specific features or functionalities that you were looking for.

Note: even though we don't have tenpy and Yao integrations in our roadmap, you can make a Fork of PennyLane and create your own implementation if you want to.

[mavzolej]

Thanks for quick response! Yao is particularly good at "exact" simulation of large quantum circuits. When the number of qubits is large enough so that one cannot store the entire statevector, one option is to use tensor networks. However, another option is, in some sense, to utilize the sparsity of the unitary matrix and use Krylov subspace methods for simulating evolution, see Yao's time_evolve method.

Tenpy, just like quimb, is a general-purpose framework for simulating various lattice Hamiltonians (spins, fermions, bosons). It has both TEBD and TDVP engines. It doesn't yet support PEPS so 2D stuff if currently simulated via MPS. Tenpy vs quimb is a tight competition, tenpy may work better for continuous time evolutions (TDVP) on arbitrary lattices.

I would also like to point your attention at the quspin package which seems to currently be the leader in terms of exact diagonalization. It's really good at taking into account Hamiltonian symmetries which is big deal when simulating materials with crystal structures.

[CatalinaAlbornoz]

Thank you @mavzolej !

This is really good to know. At the moment we don't have capacity to add these integrations but we'll keep it in mind in case we can add them in the future. Feel free to open another enhancement request in the future if you're looking for another feature that you need and you can't find in PennyLane.