Laser protection of Rydberg atoms over the gate operation

Laser-excited Rydberg atoms have shown great potential for various applications in atomic [1-7] and photonic [8-15] quantum technologies. One commonly used method for Rydberg quantum gates is the π-gap-π scheme, where atoms are left in Rydberg states for a gap period of time while other atoms are under laser rotations. However, it has been observed that for highly excited Rydberg atoms, the subsequent de-exciting π pulse cannot fully return the Rydberg population to the qubit basis. This limits the use of Rydberg states with larger interaction to loss ratio.



To address this issue, I propose a scheme that operates by relative intensity modulation of two lasers used in Rydberg excitation, as described in [15]. The proposed 2π operation bypasses the conventional π-gap-π schemes [1,8,9] and features continuous laser shielding of the Rydberg atoms from environmental noise. This allows for a more efficient and reliable retrieval of the qubit basis, even for highly excited Rydberg atoms. Overall, our proposed scheme offers a promising approach for improving the performance of Rydberg-based quantum gates and their potential applications in quantum technologies.



References:

1. 1- M. Khazali, K. Mølmer, Phys. Rev. X 10, 021054 (2020).
   
   2- M. Khazali, Quantum 6, 664 (2022).
   
   3- M Khazali, Phys. Rev. Research 3, L032033 (2021)
   
   4- M. Khazali, Phys. Rev. A 98, 043836 (2018)
   
   5- M. Khazali, H. W. Lau, A. Humeniuk, C. Simon, Phys. Rev. A 94, 023408 (2016)
   
   6- Khazali, M., & Lechner, W. Communications Physics 6, 57 (2023).
   
   7- Khazali, M. (2023). Subnanometer confinement and bundling of atoms in a Rydberg empowered optical lattice. arXiv preprint arXiv:2301.04450.
   
   8- M. Khazali, K. Heshami, C. Simon, Phys. Rev. A 91, 030301 (2015)
   
   9- M. Khazali, C. Murry, T. Pohl, Phys. Rev. Lett. 123, 113605 (2019)
   
   10- M. Khazali, K. Heshami, C. Simon J. Phys. B, 50, 21 (2017)
   
   11- Khazali, M. (2022). Photonic interface for long-distance entanglement of logical-qubits. arXiv preprint arXiv:2204.08522.
   
   12- M. Khazali, IJAP 10, 19 (2021)
   
   13- Khazali, Mohammadsadegh. "Applications of Atomic Ensembles for Photonic Quantum Information Processing and Fundamental Tests of Quantum Physics." Ph.D. thesis, University of Calgary (2016).
   
   14- H Kaviani, et. al, New J. Phys. 15, 085029 (2013)
   
   15- M. Khazali, Optics Express 31(9), 13970-13980 (2023)