  Recurrent neural networks (RNNs) are a class of neural networks that have
emerged from the paradigm of artificial intelligence and has enabled lots of
interesting advances in the field of natural language processing.
Interestingly, these architectures were shown to be powerful ansatze to
approximate the ground state of quantum systems. Here, we build over the
results of [Phys. Rev. Research 2, 023358 (2020)] and construct a more powerful
RNN wave function ansatz in two dimensions. We use symmetry and annealing to
obtain accurate estimates of ground state energies of the two-dimensional (2D)
Heisenberg model, on the square lattice and on the triangular lattice. We show
that our method is superior to Density Matrix Renormalisation Group (DMRG) for
system sizes larger than or equal to $14 \times 14$ on the triangular lattice.
