Robust Preparation of Many-body Ground States in Jaynes-Cummings Lattices*

Strongly-correlated polaritons in Jaynes-Cummings (JC) lattices can exhibit quantum phase transitions between the Mott-insulating and the superfluid phases at integer fillings. However, it is often challenging to prepare such many-body states with high accuracy. Here we present an approach for the robust preparation of many-body ground states in a finite-sized JC lattice. Using the ground states in the deep Mott-insulating or deep superfluid regimes as initial state, which can be generated accurately via engineered pulse sequences, and employing optimized nonlinear ramping, we demonstrate that many-body ground states in the intermediate regimes of a JC lattice can also be generated with high fidelity. For each given ramping trajectory, we derive an optimal ramping index with a Landau-Zener-type of estimation on finite-sized systems. Our numerical simulation shows that with the optimal ramping index on an appropriate trajectory, the fidelity of the generated states can remain close to unity in almost the entire parameter space. This method is general and can be applied to many other systems.
1. K. Cai et al., arXiv: :2007.02218 [quant-ph].