Abstract
The nature of causality remains one of the key puzzles in science. In quantum theory, the causal structure is not subject to quantum uncertainty and plays rather a background role. The process matrix formalism (PMF) has introduced indefinite causal structures (ICS) by assuming validity of quantum theory in local laboratories while relaxing the global definite causal order between them. Looking for the possible applications of the PMF has been the subject of growing interest in the scientific community as the PMF could provide communication and computational resources not realizable via standard quantum theory. The main goal of this project is to trace both the foundational and practical sides of the ICS in the PMF. Its central topics put under scrutiny implications of the PMF for thermodynamics and its fundamental laws, the underlying mathematical structure, and further benefits offered by ICS for practical tasks.
The project is funded by the Austrian Science Fund (FWF) as the Principal Investigator Project PAT 4559623. If you are interested in a collaboration or need additional information on the project, please do not hesitate to write me at my email.
Project Outcomes
- Correlations in a quantum switch-based heat engine with measurements: A proof-of-principle demonstration (arXiv, 2025)
- Activation of thermal states by coherently controlled thermalization processes (New J. Phys., 2025)
- Estimation of multivariate traces of states given partial classical information (arXiv, 2025)
- Parallel ergotropy: Maximum work extraction via parallel local unitary operations (Phys. Rev. A, 2025)
- Dimension-independent weak value estimation via controlled SWAP operations (Phys. Rev. Research, 2024)
- Tests of macrorealism in meson oscillation physics (Phys. Rev. A, 2024)
- Universal Quantum Computation via Superposed Orders of Single-Qubit Gates (arXiv, 2023)
- Beyond Shannon Limits: Quantum Communications through Quantum Paths (IEEE J. Sel. Areas Commun., 2023)
- Measuring incompatibility and clustering quantum observables with a quantum switch (Phys. Rev. Lett., 2023)
- The Quantum Internet: Enhancing Classical Internet Services One Qubit at A Time (IEEE Network, 2022)
- How Deep the Theory of Quantum Communications Goes: Superadditivity, Superactivation and Causal Activation (IEEE Commun. Surv. Tutor., 2022)
- Work extraction from coherently activated maps via quantum switch
(Phys. Rev. A, 2022)
Type
Stand-Alone Project (with international cooperations)