  Entanglement renormalization can be viewed as an encoding circuit for a
family of approximate quantum error correcting codes. The logical information
becomes progressively more well-protected against erasure errors at larger
length scales. In particular, an approximate variant of holographic quantum
error correcting code emerges at low energy for critical systems. This implies
that two operators that are largely separated in scales behave as if they are
spatially separated operators, in the sense that they obey a Lieb-Robinson type
locality bound under a time evolution generated bya local Hamiltonian.
