Development of solid state hardware for processing quantum information and practical implementation of quantum algorithms is one of the most exciting problems in contemporary solid state physics. It is generally believed that quantum computers may outperform classical computers in many ways in the future. We participate in the EU FP6-IST EuroSQIP network, whose task it is to develop basic elements for quantum computers, quantum bits, on the basis of superconducting electronic circuits.
The quantum bit, or qubit, is a controllable two-state system, which can maintain quantum coherence for a sufficiently long time to allow quantum-logical operations to be performed. Our research is focused on theoretical aspects of superconducting qubits: analysis of the measurement process, design of qubit networks, and investigation of the decoherence problem. Although several groups have demonstrated operations on single superconducting qubits, the Quantum Device Physics Laboratory at MC2 among them, it is still a great challenge to demonstrate quantum algorithm operations on a (even small) network of qubits.
A novel aspect of the qubit research concerns strong interaction of superconducting qubits with microwave photons in superconducting cavity. This interaction is used for controllable qubit-qubit coupling, and also for generation of non-classical photonic states in the cavity.