Bachelor defense by Sophia Krasnik

Characterizing Quantum Noise in Multi-Qubit systems. 

Abstract: The development of large scale reliable quantum computers would be a substantial addition to the evolution of modern technology. The current quantum computers are plagued by errors due to the nature of qubits, that store quantum information. Therefore, quantum error correction (QEC) algorithms have been developed to detect and correct errors. However, this is no easy task and decoding the errors often relies on the assumption that errors occur independently across qubits. This project investigates the validity of QEC through the characterisation of noise in multi-qubit systems. Using numerical simulations and the Universal Lindblad Equation, the occurrence of correlated and multi-qubit errors are analysed using stabilisers. It is concluded that for certain systems and models correlated errors may occur, hinting at the possible need for QEC to be altered to encompass a broader range of errors.