Realization of a crosstalk-avoided quantum network node using dual-type qubits of the same ion species

Abstract

Generating ion-photon entanglement is a crucial step for scalable trapped-ion quantum networks. To avoid the crosstalk on memory qubits carrying quantum information, it is common to use a different ion species for ion-photon entanglement generation such that the scattered photons are far off-resonant for the memory qubits. However, such a dual-species scheme can be subject to inefficient sympathetic cooling due to the mass mismatch of the ions. Here we demonstrate a trapped-ion quantum network node in the dual-type qubit scheme where two types of qubits are encoded in the S and F hyperfine structure levels of 171Yb+ ions. We generate ion photon entanglement for the S-qubit in a typical timescale of hundreds of milliseconds, and verify its small crosstalk on a nearby F-qubit with coherence time above seconds. Our work demonstrates an enabling function of the dual-type qubit scheme for scalable quantum networks.

Fast, Universal Scheme for Calibrating Microwave Crosstalk in Superconducting Circuits

“…Despite recent demonstrations of quantum supremacy [4][5][6][7][8][9][10], utility [11], and quantum logical error correction [12][13][14][15][16][17][18], achieving scalable quantum computing is still obstructed by numerous challenges [19]. Among these, crosstalk is well-recognized in various quantum computing systems [20][21][22][23][24][25][26][27][28]. Specifically, microwave crosstalk in superconducting circuits significantly impacts system performance by inducing unwanted quantum state transitions and gate errors [29][30][31][32].…”