High-fidelity population transfer in a Josephson three-level atom with optimized level anharmonicity

Speeding up adiabatic population transfer in a Josephson qutrit via counter-diabatic driving

“…The suitable level structure is very helpful to implement the robust quantum manipulation. (iv) Different from the previous works [21,35,60], the present three-level system is selected at the magic point of n 0.5 d = , which contributes to remove the dephasing effect and then to prolong the system decoherence time greatly. (v) During the accelerated and reversible transfer process, the intermediate state añ | is almost not populated within the operation time, which makes the robust inversion insensitive to spontaneous emission caused by añ | .…”

“…Here the fast oscillating term n s 2 with higher frequency 2 s w has been omitted well under the rotation wave approximation (RWA) [21,27]…”

“…Quantum population transfer (QPT), acting as a coherent operation, is a critical issue in the context of quantum information processing [16][17][18][19]. The performance of optimal QPT has drawn increasing attention [20][21][22][23]. Based on the powerful method of stimulated Raman adiabatic passage (STIRAP) [16,24], a great deal of effort has been devoted to studying QPTs with Josephson three-level systems both theoretically and experimentally [25][26][27][28][29].…”

High-fidelity quantum state transfer using Cooper-pair box qubits

“…At the same time, an effective three-level subsystem needs to be operated, as mentioned below, and then a large energy gap DE sa should be existed between a j i and s j i. Taking into account these two aspects, we select the three-level atom with the optimized level anharmonicity at b ¼ 1:5 (with the leakage error 6 0:92% and the sufficiently separated DE sa ¼ 1:73 GHz) to study the coherent manipulations [30].…”

“…One is reversibly transferring quantum states in a feasible way [16], which is requisite for the storage and retrieval of information. Another is how to enhance the transfer fidelity by reducing the decoherence effects [25,29,30]. To realize the perfect QST, one should combine the above two aspects to reversibly implement the robust state transfer, which is highly preferable for the scalable quantum information processing.…”