Comment on 'Charge-Qubit Operation of an Isolated Double Quantum Dot'

摘要

In the recent Letter, J. Gorman et al. claim that they have realized a solid state qubit based on a double quantum dot geometry with a long decoherence time, τ_2 ≈ 200 ns. However, we have found a number of inconsistencies in the data and the statements concerning demonstration of coherent oscillations. We believe that the observed oscillating signal cannot be evidence of coherent oscillations in the double quantum dot, either. The following we consider the most serious inconsistencies in their interpretations.