Research Projects

Quantum physics is rapidly translating into quantum technologies that are expected to have game-changing impacts on our ability to process information. This ability, in turn, can revolutionize the way we perform computations, communicate, measure signals and probe the universe. So far, the vast majority of quantum technology paradigms have relied on our ability to coherently manipulate one or more quantum two-level systems, or qubits. While this approach has already met with overwhelming success, quantum physics offers us the ability to work with systems with more than just two levels, which we will refer to as high-dimensional quantum systems, or qudits. The use of qudits for quantum technology applications is becoming increasingly feasible thanks to the tremendous recent progress in experimental control and manipulation of multilevel quantum systems. Furthermore, quantum features such as entanglement can manifest in qudits in ways that are not possible in qubits, which in turn can enable novel tests of quantum physics as well as open new paradigms for quantum information processing. This project will aim to theoretically explore the use of qudits for quantum technology applications, with a particular focus on quantum sensing. We will adopt a holistic approach by focusing on three themes relevant to various aspects of practical quantum sensor operation. These themes include low-entropy state initialization in multi-qudit arrays, preparation and use of entangled qudit states for quantum sensing, and many-body collective phenomena in qudit ensembles. We will use tools from quantum optics theory to explore these themes on various platforms such as trapped ions, superconducting circuits and atom-cavity systems. The research carried out will be at the interface of theory and experiment, and our work will serve as a bridge to connect abstract quantum information ideas with current hardware platforms. Specific problems targeted by the proposed research are detailed in the Technical Document. This project will push the boundaries of qudit-based quantum sensing in multiple directions. First, the project will significantly contribute to the development of multi-ion laser cooling protocols for state initialization in trapped ion systems. Second, the project will generate novel entangling gates and sensor protocols for qudit-based quantum sensors, which will directly find applications in emerging areas such as quantum-enhanced multiparameter metrology. Third, the project will shed light on the novel ways in which collective effects such as many-body energy gaps manifest in qudit ensembles. Overall, the project will provide concrete recipes that will guide experimental studies of many-body qudit systems.