Powered by Indico
v3.1.1
How should one model systems that include agents who are themselves using quantum theory? The bare formalism of quantum mechanics does not provide a straightforward answer to such foundational questions; however, they may still be investigated with a theorist's tool – the thought experiment. We give a state-of-the-art overview on quantum thought experiments involving observers, from the basic Wigner's friend to the recent Frauchiger-Renner setup, and introduce a software package that allows users to design and run simulations of thought experiments in quantum theory. In particular, it covers cases where reasoning agents are modelled as quantum systems, such as Wigner's friend experiment. Users can customize the protocol of the experiment, the inner workings of agents (e.g. the quantum circuit that models their reasoning process), the abstract logical system used (which may or not allow agents to combine premises and make inferences about each other's reasoning), and the interpretation of quantum theory used by different agents (for example collapse, Copenhagen, many worlds or Bohmian mechanics).
The software is written in a quantum programming language, ProjectQ (projectq.ch), and as such the simulations of thought experiments can in principle run on quantum hardware. The software is currently in beta version, publicly accessible on GitHub (github.com/jangnur/qthought). As an example, we model the Frauchiger-Renner extended Wigner's friend thought experiment, where agents are allowed to measure each other's physical memories, and try to make inferences about each other's reasoning.