C-NOT gate based on ultracold Rydberg atom interactions

The Rydberg states of neutral atoms are strongly polarisable and possess long lifetimes because of high energies which can lead to strong and long range dipole-dipole interactions. The energy levels corresponding to these states are shifted because of dipole-dipole interactions and can be used to block transitions of more than one excitation in the Rydberg regime. This reputed Rydberg blockade is obtained when the excitation is shifted out of resonance by these interactions. Electromagnetically induced transparency (EIT) is sensitive to a small detuning. At large distances, up to several micrometers, the interactions can interrupt the EIT consequence. Herein we investigate a novel scheme based on EIT and Rydberg blockade and performed a simulation of a controlled-NOT (C-NOT) quantum gate which is critical for quantum computation by using neutral atoms.