Mavalankar, A and Pei, T and Gauger, E M and Warner, J H and Briggs, G A D and Laird, E A (2016) Photon-assisted tunneling and charge dephasing in a carbon nanotube double quantum dot. Physical review B, 93 (23): 235428. ISSN 2469-9950
Mavalankar_et_al._2016_Photon_assisted_tunneling_and_charge_dephasing_in_a_carbon_nanotube_double_quantum_dot.pdf - Published Version
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Abstract
We report microwave-driven photon-assisted tunneling in a suspended carbon nanotube double quantum dot. From the resonant linewidth at a temperature of 13 mK, the charge-dephasing time is determined to be 280 ± 30 ps. The linewidth is independent of driving frequency, but increases with increasing temperature. The moderate temperature dependence is inconsistent with expectations from electron-phonon coupling alone, but consistent with charge noise arising in the device. The extracted level of charge noise is comparable with that expected from previous measurements of a valley-spin qubit, where it was hypothesized to be the main cause of qubit decoherence. Our results suggest a possible route towards improved valley-spin qubits.