Thema der Dissertation:
Development and Application of Optimal Control Methods for Quantum Technologies
Development and Application of Optimal Control Methods for Quantum Technologies
Abstract: The precise control of quantum technologies enables the development of a wide range of promising quantum technologies. These technologies allow for beating the limits of their classical pendants and outperform them in various tasks. This thesis employs and expands a variety of methods and concepts of optimal control theory in order to address different problems in quantum technologies and work towards their realization. Schrödinger cat states present a particularly versatile set of states, that have a broad range of applications for all types of quantum technologies. We employ optimal control theory to investigate how cat states can be prepared in different physical systems. This allows us to investigate the role of higher order nonlinearities in anharmonic resonators. Further, this enables the identification of strategies for cat state preparation in the presence of higher order anharmonicities and an analysis if they can be exploited as resource. Additionally, we develop a set of functionals, which allow for optimizing towards arbitrary cat states. This facilitates the preparation of cat states even in systems, where the reachable set of states is not immediately apparent. Quantum computing is a particularly prominent quantum technology and promises a completely new paradigm for computing. Crosstalk, the undesired interaction between different parts of a quantum processor, poses a major challenge across various architectures. Therefore, we utilize concepts from optimal control to introduce the perfect entangler spectrum as a tool to detect operational crosstalk, caused by spectator qubits. This allows us to identify parameter regimes of superconducting qubits, which exhibit crosstalk and determine the underlying mechanisms. In addition, we utilize optimal control and parameter optimizations to explore mitigation strategies for the different crosstalk mechanisms. Our work paves the way for systematically eliminating crosstalk, when scaling up quantum computing architectures. The precise control of quantum technologies enables the development of a wide range of promising quantum technologies. These technologies allow for beating the limits of their classical pendants and outperform them in various tasks. This thesis employs and expands a variety of methods and concepts of optimal control theory in order to address different problems in quantum technologies and work towards their realization. Schrödinger cat states present a particularly versatile set of states, that have a broad range of applications for all types of quantum technologies. We employ optimal control theory to investigate how cat states can be prepared in different physical systems. This allows us to investigate the role of higher order nonlinearities in anharmonic resonators. Further, this enables the identification of strategies for cat state preparation in the presence of higher order anharmonicities and an analysis if they can be exploited as resource. Additionally, we develop a set of functionals, which allow for optimizing towards arbitrary cat states. This facilitates the preparation of cat states even in systems, where the reachable set of states is not immediately apparent. Quantum computing is a particularly prominent quantum technology and promises a completely new paradigm for computing. Crosstalk, the undesired interaction between different parts of a quantum processor, poses a major challenge across various architectures. Therefore, we utilize concepts from optimal control to introduce the perfect entangler spectrum as a tool to detect operational crosstalk, caused by spectator qubits. This allows us to identify parameter regimes of superconducting qubits, which exhibit crosstalk and determine the underlying mechanisms. In addition, we utilize optimal control and parameter optimizations to explore mitigation strategies for the different crosstalk mechanisms. Our work paves the way for systematically eliminating crosstalk, when scaling up quantum computing architectures.
Zeit & Ort
16.12.2025 | 16:30
Hörsaal B (0.1.01)
(Fachbereich Physik, Arnimallee 14, 14195 Berlin)