Putting theory in its place: The relationship between universality arguments and empirical constraints

Abstract

In light of its empirical undetectability, physicists have attempted to establish Hawking radiation as universal-as a phenomenon that should appear regardless of the possible details of quantum gravity, whatever those details might be. But, as pointed out in a recent article by Gryb, Palacios, and Thébault (2019), these universality arguments for Hawking radiation seem broadly unconvincing compared to the Wilsonian renormalization-group universality arguments for condensed matter physics.Motivated by their apparent failure, compared with the overwhelming success of universality arguments in so many other contexts, I address the question: in which situations should we expect to be able to construct successful universality arguments? In other words, which situations are 'universality-argument-apt'? I distinguish between two notions of success for a universality argument: 'strength' and 'relevance'. I argue that we should only expect to be able to construct universality arguments that are successful in the sense of being significantly relevant to a given domain if 1 we know enough about how that domain's micro-physics is structured, or 2 we are able to empirically test the domain's macro-behaviour, or if we are in both situations at once. These conditions are useful, most obviously, as a clarification of what universality arguments are capable of. But I argue that they are also useful for two less direct reasons: they clarify the status of analogue experimentation, and thereby show us where we stand in our search for empirical confirmation of Hawking radiation.

How to Engineer a Quantum Wavefunction

“…Plausibly, however, we take our arguments to imply that one may understand PCjQ H R P C to be nontrivial even if one expects trivial inductive support in cases in which the target system is entirely inaccessible and thus that PCjQ R P C 0 (cf. Dardashti et al 2019;Field, forthcoming). very reasonable assumption that the elementary objects at play in the source and target systems of an analogue quantum simulation are quantum objects.…”

“…The potential implications of such quantum technology are powerful, wide ranging, and radical. In this article, our focus is on the particular context of analogue quantum simulation in which a well-controlled quantum system in the lab is specifically deployed by scientists to learn about features of another quantum system to which they do not have direct access (Dardashti, Thébault, and Winsberg 2017;Dardashti et al 2019;Thébault 2019;Crowther, Linnemann, and Wüthrich 2019;Evans and Thébault 2020;Hangleiter, Carolan, and Thébault 2022;Field forthcoming;Bartha 2022).…”

Introduction: A New Instrument of Science?

“…An important outstanding issue is the whether there are limits on the degree of confirmation that is possible for exotic target systems such as black holes. See (Field, 2021).…”