Landau–Zener–Stückelberg Interference in Nonlinear Regime
Tong Wu1,2,3†, Yuxuan Zhou2,3†, Yuan Xu2,3, Song Liu2,3,4, Jian Li2,3,4**
1Department of Physics, Harbin Institute of Technology, Harbin 150001 2Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055 3Shenzhen Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055 4Center for Quantum Computing, Peng Cheng Laboratory, Shenzhen 518055
Abstract：Landau–Zener–Stückelberg (LZS) interference has drawn renewed attention to quantum information processing research because it is not only an effective tool for characterizing two-level quantum systems but also a powerful approach to manipulate quantum states. Superconducting quantum circuits, due to their versatile tunability and degrees of control, are ideal platforms for studying LZS interference phenomena. We use a superconducting Xmon qubit to study LZS interference by parametrically modulating the qubit transition frequency nonlinearly. For dc flux biasing of the qubit slightly far away from the optimal flux point, the qubit excited state population shows an interference pattern that is very similar to the standard LZS interference in linear regime, except that all bands shift towards lower frequencies when increasing the rf modulation amplitude. For dc flux biasing close to the optimal flux point, the negative sidebands and the positive sidebands behave differently, resulting in an asymmetric interference pattern. The experimental results are also in good agreement with our analytical and numerical simulations.
Koch J, Yu T M, Gambetta J, Houck A A, Schuster D I, Majer J, Blais A, Devoret M H, Girvin S M and Schoelkopf R J 2007 Phys. Rev. A76 042319
[3]
Barends B, Kelly J, Megrant A, Sank D, Jeffrey E, Chen Y, Yin Y, Chiaro B, Mutus J, Neill C, O'Malley P, Roushan P, Wenner J, White T C, Clel, A N and Martinis J M 2013 Phys. Rev. Lett.111 080502
[4]
Barends R, Kelly J, Megrant A, Veitia A, Sank D, Jeffrey E, White T C, Mutus J, Fowler A G, Campbell B, Chen Y, Chen Z, Chiaro B, Dunsworth A, Neill C, O'Malley P, Roushan P, Vainsencher A, Wenner J, Korotkov A N, Clel, A N and Martinis J M 2014 Nature508 500
Li J, Silveri M P, Kumar K S, Pirkkalainen J M, Vepsäläinen A, Chien W C, Tuorila J, Sillanpää M A, Hakonen P J, Thuneberg E V and Paraoanu G S 2013 Nat. Commun.4 1420
[8]
Silveri M P, Kumar K S, Tuorila J, Li J, Vepsäläinen A, Thuneberg E V and Paraoanu G S 2015 New J. Phys.17 043058
Wu Y, Yang L P, Gong M, Zheng Y, Deng H, Yan Z, Zhao Y, Huang K, Castellano A D, Munro W J, Nemoto K, Zheng D N, Sun C P, Liu Y X, Zhu X and Lu L 2018 npj Quantum Inf.4 50
2019, Vol. 36 
