Coupled Josephson qubits: characterization of low-frequency charge noise

The realization of coupled qubit setups is a fundamental step towards implementation of universal quantum computing architectures. Solid state nano- devices, despite being very promising from the point of view of scalability and integration, strongly suffer from various noise sources. Particular detrimental role is played by low-frequency noise components. Here we identify stability conditions against low-frequency charge noise of two Josephson qubits in a fixed coupling scheme implementation. The effects of adiabatic noise in an i-SWAP protocol is discussed. Reduced sensitivity to charge flutuations with respect to the single qubit setup is predicted.