SAMOP 2023 – scientific programme

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QI: Fachverband Quanteninformation

QI 20: Concepts and Methods II

QI 20.5: Talk

Wednesday, March 8, 2023, 15:30–15:45, B302

Graph state preparation with noisy interactions — •Konrad Szymanski — Universität Siegen, Siegen, Germany

Graph states are regarded as a testing ground of various quantum information schemes – they are useful in analysis of e.g. cryptography, measurement-based quantum computation, error correction, and metrology. Their preparation relies on the interaction pattern provided by a graph – an Ising-like Hamiltonian Ĥ is built from it and the graph state is the result of evolution of the multiqubit |+⟩^{⊗ N} state under Ĥ. Due to the simplicity, implementation is possible for a wide array of physical systems, including ion traps, nitrogen vacancies, and superconducting qubits.

However, such realizations invariably suffer from noise, which presents itself in a multitude of ways: the engineered interactions may have imperfect strengths, additional transitions may arise, and the systems rarely can be protected from coupling with the outside world.

All of these contribute to the reduced utility of the produced quantum states. Here, I investigate the effects of preparation noise in this context. In particular, imperfect interaction strengths effectively lead to an ensemble of graph states being prepared, which still possess some of the desirable qualities of the perfectly prepared state. Theoretical considerations are compared with real-world implementations of graph states.