# Ground-state blockade of Rydberg atoms and application in entanglement generation

## TL;DR

This paper introduces a ground-state blockade mechanism using Rydberg-antiblockade and Raman transitions, enabling high-fidelity entanglement of multiple atoms while avoiding excited state decay.

## Contribution

It presents a novel ground-state blockade method based on Rydberg interactions and quantum Zeno effect, facilitating efficient entanglement generation in atomic systems.

## Key findings

- High-fidelity two-atom entanglement achievable
- Feasibility demonstrated with current experimental parameters
- Ground-state encoding reduces spontaneous emission effects

## Abstract

We propose a mechanism of ground-state blockade between two $N$-type Rydberg atoms in virtue of Rydberg-antiblockade effect and Raman transition. Inspired by the quantum Zeno effect, the strong Rydberg antiblockade interaction plays a role in frequently measuring one ground state of two, leading to a blockade effect for double occupation of the corresponding quantum state. By encoding the logic qubits into the ground states, we efficiently avoid the spontaneous emission of the excited Rydberg state, and maintain the nonlinear Rydberg-Rydberg interaction at the same time. As applications, we discuss in detail the feasibility of preparing two-atom and three-atom entanglement with ground-state blockade in closed system and open system, respectively, which shows that a high fidelity of entangled state can be obtained with current experimental parameters.