Tools from Quantum System and Control Theory

• Applicant: Dr. Thomas Schulte-Herbrüggen
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 164540649

In order to fully exploit the advantageous properties of diamond NV centers as quantum registers or as quantum processors, the endurance of the memory and the precision of its read/write processes has to be taken to the limit. In quantum processors, analogous requirements hold for the computational gates. At the same time the system should be protected against relaxative losses. Moreover, in spite of state-of-the-art material engineering, the coupling architecture among the neighboring qubits is bound to have minor yet inevitable (dipolar) long-range coupling interactions. Thus a realistic architecture (hardware) is usually non-ideal and has to be compensated for by the steering controls (software). — In order to meet the combination of all these challenges, numerical methods of optimal control are tantamount. Therefore, it is the scope of this subproject to provide methods and algorithms for designing optimal controls under given non-idealty and experimental limitations. They may also comprise constraints as keeping the system dynamics In some decoherence-protected subspace or amount to compromised external controls. Upon further refinement, one has to address a system with partially unknown parameters of the master equation.

• DFG Programme: Research Units
• Subproject of: FOR 1482: Quantum Computing in Isotopically Engineered Diamond
• Participating Person: Professor Dr. Steffen Glaser