Seminár Katedry teoretickej fyziky - Natália S. Móller (6.12.2022)

v utorok 6.12.2022 o 14:00 hod. v miestnosti F2/125

29. 11. 2022 12.28 hod.
Od: Peter Maták

Prednášajúci: Natália S. Móller (Fyzikálny ústav SAV)

Názov: Indefinite causal order: gravitational proposals and definitions of events in perspective

Termín: 6.12.2022, 14:00 hod., miestnosť F2/125

Time in general relativity is dynamical and the ticking rates of clocks experiencing different gravitational fields are distinct. Thus, puzzling effects could happen in a theoretical configuration where a massive body is in a quantum superposition state of different positions. The idea of indefinite causal order comes from the possibility that, in these configurations, the causal relations among events would be in a superposition state as well. For instance, two events could be in a superposition of being in the past and future of each other. It is suggested that these configurations could be tested operationally using the proper times measured by clocks lying on such quantum spacetime.

An important research goal nowadays is to find means compatible with the current technological capabilities that make these theoretical ideas possible to be tested. Here I will talk about our more recent results, where we show how to simulate an indefinite causal order with accelerated agents, and how to perform it with the gravity of Earth with current technology. Moreover, with the same techniques, it is possible to optimize these tasks in a quantum spacetime, what makes a hypothetical experiment several orders of magnitude more efficient.

Beyond the discussion of applicability in experiments, it is also important to understand the fundamentals and interpretations of each proposal in the field of indefinite causal order. The interpretation of such tasks are under discussion and there is absolutely no consensus among the specialists. This disagreement is based on the fact that many different definitions of events are being considered by authors. I will raise this discussion in an unbiased way, summarizing all the definitions of events in the field of indefinite causal order and how they affect the interpretation of different proposals.