QUROPE Quantum Information Processing and Communication in Europe

We propose a sequence of pulses intended to preserve the state of a qubit in the presence of strong, coherent coupling to another quantum system. The sequence can be understood as a generalized swap sequence and works in formal analogy to the well-known spin echo. Since the resulting effective decoherence rate of the qubit state is strongly influenced by the additional system, this sequence might serve to protect its quantum state as well as negating the effects of the coherent coupling. A possible area of application is in large-scale quantum computing architectures, where spectral crowding of the resources might necessitate a method to mitigate residual couplings.