Browsing by Author "Huotari, Petri"

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  • Adaption of mechanical engineering process to concurrent product development
    (1997) Karling, Sami
     Helsinki University of Technology | Master's thesis
  • Kannustejärjestelmän kehittäminen tuotekehitystyöhön
    (1996) Rantamäki, Tomi
     Helsinki University of Technology | Master's thesis
  • Entanglement dynamics between pairs of qubits in a noisy quantum information processor
    (2024-06-17) Huotari, Petri
     Perustieteiden korkeakoulu | Bachelor's thesis
    One of the issues remaining in quantum computing is the noise that systems experience through interactions with an environment. These interactions lead to decoherence processes destroying the quantumness of the qubits. It is particularly interesting how incoherent noise affects entanglement between qubits. For different initial conditions on a bipartite system, the decoherence process leads to the entanglement sudden death effect and causes entanglement sudden birth in the environment. Quantum channels allow us to explore these phenomena since they enable the mathematical modeling of incoherent errors and the creation of realistic noise models. In this thesis, we studied entanglement dynamics caused by the system-environment interactions. We present the methods for modeling and applying different types of incoherent noise via the operator-sum representation and the master equation approach, in addition to showcasing the concept of concurrence as an entanglement measure. In particular, we have studied the decay of concurrence under various quantum channels on different simulators. The results included both decay of concurrence converging to zero in infinite time and finite time disentanglement, depending on the type of noise and initial state conditions considered. We determined the finite disentanglement and birth of entanglement times in the amplitude damping channel case. Furthermore, a combination of individual quantum channels was used to fit the concurrence function to data obtained from a fake backend with a faithful noise model to its real-life counterpart. We were able to recreate the noise of realistic quantum devices by inputting the extracted thermal relaxation time T1 and dephasing time T2 to the combined quantum channel. Overall, the obtained results illustrated the potency of these methods in the study of entanglement dynamics.