Ladina Hausmann

In Wigner's friend-type experiments, unlike in standard QIP setups, the participating agents are modelled as quantum systems. Recent versions of such experiments have revealed that the usual rules for combining information held by different agents are inconsistent with quantum theory. Here, we show that this insight is relevant to paradoxes in quantum gravity, such as the black hole firewall paradox. This is because their structure is similar to Wigner's friend experiments: they rely on combining knowledge of multiple agents, some of whom enter the black hole, which is treated as a quantum system.