Capacitively Coupled Charge Qubits: Difference between revisions

We will refer to <math>\epsilon_i</math> and <math>\Delta_i</math> as the '''detuning''' and '''tunnel coupling''' of qubit <math>i</math>, respectively.

A major issue with charge qubits is that they are very susceptible to '''charge noise''', which occurs when charge fluctuations outside the system induce undesired shifts in the parameters of the Hamiltonian. The goal of a sweet spot is to find a point in the parameter space where the energy levels are as invariant to the shifts as possible.

The most dominant noise source is due to the shifts in the detuning. It is believed that the only point at which the first order dependence on the detunings disappears is at <math>\epsilon_1 = \epsilon_2 = 0</math>.