Wavelet construction of bosonic entanglement renormalization circuits
Freek Witteveen, Michael Walter
Abstract
Entanglement renormalization is a unitary real-space renormalization scheme. The corresponding tensor network states are known as MERA, and are particularly well-suited to describe quantum systems at criticality. In this work we explain how one can construct Gaussian bosonic quantum circuits that implement entanglement renormalization for ground states of arbitrary free bosonic chains. The construction is based on biorthogonal wavelet filters, and the dispersion relation of the Hamiltonian is translated to a filter design problem. We prove an approximation result that relates properties of the filters to the accumulation of errors in the MERA state. Finally, we explain how the continuum limit (a free bosonic quantum field) emerges naturally from the wavelet construction.