Unifying variational methods for simulating quantum many-body systems

Understand

We introduce a unified formulation of variational methods for simulating ground state properties of quantum many-body systems.

• The key feature is a novel variational method over quantum circuits via infinitesimal unitary transformations, inspired by flow equation methods.
• Variational classes are represented as efficiently contractible unitary networks, including the matrix-product states of density matrix renormalization, multiscale entanglement renormalization (MERA) states, weighted graph states, and quantum cellular automata.
• In particular, this provides a tool for varying over classes of states, such as MERA, for which so far no efficient way of variation has been known.