Quantum simulation of open quantum systems with ultracold polar molecules

The central spin model is paradigmatic in the theory of open quantum systems. It describes decoherence phenomena, which occur in a wide range of quantum systems ranging from quantum dots to color centers in solids and molecular nanomagnets at low temperatures. We propose a quantum simulator of the central spin model based on ultracold molecules trapped in optical tweezers. The central spin system is represented by the rotational degrees of freedom of the molecule, whereas molecular nuclear and electron spins represent a magnetically tunable spin bath. We present numerical results for a single KRb molecule in a magnetic field, which demonstrate rich quantum decoherence dynamics of rotational superpositions driven by the system - bath (nuclear electric quadrupole) interaction.