Distinguishing adiabaticity from relaxation in a Si double quantum dot charge qubit.

Ciarán Ryan-Anderson, N. Tobias Jacobson, Andrew J. Landahl

Malcolm S. Carroll, Stephen M Carr, Wayne M. Witzel +7 more

Khoi Thi Nguyen, N. Tobias Jacobson, Michael P Lilly +6 more

The interaction between a qubit and its environment provides a channel for energy relaxation which has an energy-dependent timescale governed by the specific coupling mechanism. We measure the rate of inelastic decay in a Si MOS double quantum dot (DQD) charge qubit through sensing the charge state's response to non-adiabatic driving of its excited state population. The charge distribution is sensed remotely in the weak measurement regime. We extract emission rates down to kHz frequencies by measuring the variation of the non-equilibrium charge occupancy as a function of amplitude and dwell times between non-adiabatic pulses. Our measurement of the energy-dependent relaxation rate provides a fingerprint of the relaxation mechanism, indicating that relaxation rates for this Si MOS DQD are consistent with coupling to deformation acoustic phonons.

利正 藤澤

T. Fujisawa, T. Hayashi, Sung Woo Jung +2 more

Ke Wang, Chris Payette, Yuliya Dovzhenko +2 more

We measure the interdot charge relaxation time T1 of a single electron trapped in an accumulation mode Si/SiGe double quantum dot. The energy level structure of the charge qubit is determined using photon assisted tunneling, which reveals the presence of a low-lying excited state. We systematically measure T1 as a function of detuning and interdot tunnel coupling and show that it is tunable over four orders of magnitude, with a maximum of 45 μs for our device configuration.