Robust Nuclear Spin Entanglement via Dipolar Interactions in Polar Molecules

We propose a general protocol for on-demand generation of robust entangled states of nuclear and/or
electron spins of ultracold 1Σ and 2Σ polar molecules using electric dipolar interactions. By encoding a
spin-1=2 degree of freedom in a combined set of spin and rotational molecular levels, we theoretically
demonstrate the emergence of effective spin-spin interactions of the Ising and XXZ forms, enabled by
efficient magnetic control over electric dipolar interactions.We show how to use these interactions to create
long-lived cluster and squeezed spin states.