A class of highly entangled many-body states that can be efficiently simulated

TL;DR

This paper introduces the branching MERA, a quantum circuit that efficiently generates highly entangled many-body states, enabling scalable computation of local observable expectations in complex quantum systems.

Contribution

It presents the branching MERA, a novel variational ansatz generalizing MERA, capable of representing states with volume-law entanglement scaling.

Findings

Entanglement scales with region size, not boundary, in the branching MERA.

The construction allows efficient expectation value computation.

Numerical demonstrations in 1D and 2D systems.

Abstract

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 multi-scale entanglement renormalization ansatz (MERA), and to which we refer as the branching MERA. In a lattice system in D dimensions, the scaling of entanglement of a region of size L^D in the branching MERA is not subject to restrictions such as a boundary law L^{D-1}, but can be proportional to the size of the region, as we demonstrate numerically for D=1,2 dimensions.