Defence of doctoral thesis in the field of engineering physics, Aravind Babu

Title of the doctoral thesis is "Dissipative dynamics of quantum devices beyond Lindblad model"

Quantum physics has paved the way for progress in modern technology. Most electronic devices that have made our lives easy are quantum physics products. The second quantum revolution is unfolding now, driving technology into a fully quantum world through quantum computing and communication. A quantum device is a machine whose functionality or principle of operation is governed by the laws of quantum physics. Consequently, quantum mechanical modeling is crucial for the efficient design of such devices for various quantum technology applications. Furthermore, one of the significant bottlenecks of technology is the unavoidable interaction of the quantum device with their environment, which leads to energy dissipation. Thus, for accurate modeling, one needs to consider dissipative effects too. Unfortunately, exact modeling is rather challenging and inaccessible in many cases because the environments associated with quantum systems are generally extensive and complicated. Therefore, approximative methods are used for feasible modeling. This dissertation presents general and efficient methods for modeling quantum device dynamics and their applications.

The quantum mechanical counterpart of a classical binary bit - a qubit leads modern quantum technology and computation. Superconducting qubits are the current leading choice for large-scale quantum computing. The first part of the thesis presents the dynamics and control of a specific superconducting qubit design called transmon with numerically exact methods. The results predict possible intrinsic constraints crucial for designing such quantum devices.

In general, quantum devices interacting with the environment induces system-environment correlations that include both classical and quantum features. The second part of the dissertation introduces a new technique, the correlation picture approach, that treats system-environment correlations in a tractable way. Finally, unfold the hidden correlations in existing approximative methods using the correlation picture formalism.

The potential applications of work presented in this dissertation are far-reaching, going from fundamental quantum physics problems to the efficient design of modern quantum devices.

Opponent is Associate Professor Aurelia Chenu, University of Luxembourg, Luxembourg

Custos is Professor Tapio Ala-Nissilä, Aalto University School of Science, Department of Applied Physics

Contact details of the doctoral candidate: [email protected], 0465659573

The public defence will be organised via Zoom. Link to the event

The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic thesis

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