Entanglement preparation between two distant qubits by single photon loading in a 1D waveguide QED system

Kuan-Ting Lin^1*, Yu-Chen Lin¹, Ting Hsu¹, Guin-Dar Lin^1,2

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Centre for Quantum Science and Engineering, National Taiwan University, Taipei, Taiwan

* Presenter:Kuan-Ting Lin, email:alex968.tw@gmail.com

Preparation of a desired quantum entangled state is a key step for quantum information processing and communication. Long-distance entanglement is an even more precious resource and very challenging to be constructed. In this work, we study two distant superconducting qubits coupled through a long transmission line in front of a mirror, where the resonant dipole-dipole interaction must be time-delayed. We investigate arbitrary singly-excited entangled state preparation by single photon loading from the open end of the transmission line. Here, the photon wavefunction is shaped in a way such that the time reversal of the temporal profile matches that of the spontaneous relaxation from the targeted two-distant-qubit state. We thus successfully demonstrate the formation of the entangled states such as the maximally entangled ones. We also analyze the retardation in the dynamics and the non-Markovian behavior. This work paves the way of high-fidelity quantum interface and deterministic quantum state preparation between quantum nodes with large separations.

Keywords: Resonant dipole-dipole interaction, Non-Markovian, Super- and Subradiant, Quantum state preparation, Photon loading