Speaker
Description
The entanglement of a system serves a key measure of its quantum properties that can be used to quantify its utility in quantum information processors. Nonetheless, entanglement is a notoriously challenging and expensive quantity to compute for many-body systems. In this work, we demonstrate how a new recursive formalism can be used to compute the finite temperature properties of quantum systems, including their entanglement and Renyi-2 entropies, in the canonical ensemble within an Auxiliary Field Quantum Monte Carlo (AFQMC) framework. Our approach is capable of obtaining the properties of interacting systems of arbitrary dimensions by integrating over corresponding non-interacting solutions computed via the Auxiliary Partition Function formalism using the Hubbard-Stratonovich Transformation. We show that our approach is not only more stable, but also less expensive than comparable techniques. We then employ this formalism to study the accessible entanglement of electrons in the Hubbard model in the canonical ensemble and how this entanglement differs from that in the grand canonical ensemble. We lastly show how such measures of entanglement can be used to detect the Mott insulator transition in the Hubbard model. Our approach serves as a powerful, yet relatively inexpensive approach for quantifying entanglement and detecting phase transitions in interacting quantum systems.
