Class of Highly Entangled Many-Body States that can be Efficiently Simulated

We describe a quantum circuit that produces a highly entangled state of N qubits from which one can efficiently compute expectation values of local observables. This construction yields a variational ansatz for quantum many-body states that can be regarded as a generalization of the multiscale entanglement renormalization ansatz (MERA), which we refer to as the branching MERA. In a lattice system in D dimensions, the scaling of entanglement of a region of size LD in the branching MERA is not subject to restrictions such as a boundary law LD-1, but can be proportional to the size of the region, as we demonstrate numerically.