Measuring the coherence of charge states in undoped GaAs/AlGaAs double quantum dots with photon-assisted tunnelingJie You, Hai-Ou Li, Gang Cao, Guang-Wei Deng, Ming Xiao and Guo-Ping GuoEPL, 111 1 (2015) 17001DOI: https://doi.org/10.1209/0295-5075/111/17001