Rabi Channels

Galina A. Nemova

Guanyu CHEN, Cheng Wang, Bin YANG +3 more

Rydberg atoms possess a large electric dipole moment and exhibit high sensitivity to electromagnetic signals. Receivers based on Rydberg atoms represent a novel reception mechanism, demonstrating broad application prospects in the field of communication. Current research has not addressed the influence of the operating parameters of Rydberg atomic receiver on channel capacity. This study establishes a channel capacity model for Rydberg atomic receiver based on Shannon's formula and the response mechanism of the electromagnetically induced transparency (EIT) effect. Using this model, the influences of atomic number density, laser beam waist, and coupling laser Rabi frequency on the channel capacity of Rydberg atomic receiver are analyzed. A strategy for optimizing channel capacity by adjusting the coupling laser Rabi frequency is proposed, and an analytical solution for the Rabi frequency that maximizes channel capacity is derived. The accuracy of this analytical solution is then verified through numerical simulations. The channel capacity corresponding to the analytical solution in this study is similar to the optimal channel capacity obtained using the one-dimensional optimization method (Newton’s method) and is superior to the results obtained by the quadratic interpolation method, demonstrating the effectiveness of the proposed analytical solution in optimizing the channel capacity of Rydberg atomic receiver. This research provides theoretical guidance for designing high-performance Rydberg atomic receiver and optimizing channel capacity.

Min Li, Wanfang Liu, Zheng Li

By adiabatically manipulating the Rabi frequency of the drive field, the quantum discord (QD) has been used to analyze the quantum correlation for two atoms of the ensemble under the electromagnetically induced transparency (EIT) mechanism. It is shown that, the quantum correlation of two atoms depends on the Rabi frequency of the drive field, the excitation mode, the photon number and the atom number of the ensemble. If more than half of atoms were excited, the ensemble can generate the maximum quantum correlation. Furthermore, we investigate the behavior of the quantum correlation under three decoherence channels respectively. It is found that the sudden death of the quantum correlation do not exist in any decoherence channel. Generated via the full excitation mode with a small mixed angle, the quantum correlation has a strong survival ability under the amplitude damping channel, but for a larger mixed angle, the survival ability is stronger under phase damping channel. The quantum correlation generated via the half excitation mode displays a strong survive ability for arbitrary mixed angle under the amplitude damping channel. By manipulating the Rabi frequency in this excitation mode, for an appropriate mixed angel, survivability of quantum correlation reverses under the phase damping channel and the depolarizing channel. But when the mixed angle reaches the critical value towards π/2 with the number of atoms increasing. For the low excitation mode with any mixed angle, the quantum correlation survives more easily under the amplitude damping channel, conversely, it survives more difficultly under the depolarizing channel.

Galina A. Nemova

David F. P. Pile

Stefan Grisard, Hendrik Rose, Artur V. Trifonov +9 more

The authors investigate Rabi rotations, arising in photon echoes from an ensemble of InGaAs quantum dots. To overcome the dephasing of the Rabi rotations imposed by the inhomogeneity of laser intensities, a spatially flat intensity profile is introduced. This allows to observe robust Rabi rotations and to identify efficient coupling to acoustic phonons as the dominating channel of decoherence. The insights gained are crucial for the realization of optical quantum memories based on photon echoes from semiconductor quantum dots.