Late to the party, but I will leave this here for anyone who bumps into this conversation.
The last few days I have been working on a pytorch implementation which can be found here:

  
      
      GitHub
  
  
    

flaport/torch_eunn 28

A Pytorch implementation of an efficient unitary neural network (https://arxiv.org/abs/1612.05231) - flaport/torch_eunn


  
  
    
    
  
  


The speed could probably be increased when PyTorch finally supports complex tensors