Application of Rydberg atoms to quantum computing

Abstract

Experimental aspects of an application of Rydberg atoms to quantum computing are studied. A single neutral atom trapped in an antinode of the optical lattice can represent a quantum bit. Laser excitation of two atoms in neighboring antinodes allows for obtaining of quantum entanglement of the atoms via dipole-dipole interaction which is strong for high Rydberg states. A two-qubit operation could be realized in this way. The optimal values of a principal quantum number, an interatomic distance, time of a single two-qubit operation and other parameters have been estimated. The estimates were done for 23Na and 87Rb atoms. Also experimental results of microwave spectroscopy of a few sodium Rydberg atoms at the one-photon 37S1/2 -> 37P1/2 and two-photon 37S1/2 -> 38S1/2 transitions are presented. Microwave spectroscopy can be used to detect dipole-dipole interaction between a few Rydberg atoms. The calculations showing an influence of dipole-dipole interaction on two-atom spectra are also presented. A noticeable broadening of the five-atom spectrum was observed in the experiment due to the dipole-dipole interaction.