Wormholes, emergent gauge fields, and the weak gravity conjecture
This paper revisits the question of reconstructing bulk gauge fields as boundary operators in AdS/CFT. In the presence of the ormhole dual to the thermo field double state of two CFTs, the existence of bulk gauge fields is in some tension with the microscopic tensor factorization of the Hilbert space. Here, I explain how this tension can be resolved by splitting the gauge field into charged constituents, and I argue that this leads to a new argument for the "principle of completeness", which states that the charge lattice of a gauge theory coupled to gravity must be fully populated. I also claim that it leads to a new motivation for (and a clarification of) the "weak gravity conjecture", which I interpret as a strengthening of this principle. This setup gives a simple example of a situation where describing lowenergy bulk physics in CFT language requires knowledge of highenergy bulk physics. Furthermore, this contradicts to some extent the notion of "effective conformal field theory", but in fact is an expected feature of the resolution of the black hole information problem. An analogous factorization issue exists also for the gravitational field, and I comment on several of its implications for reconstructing blackmore »
 Authors:

^{[1]}
 Harvard Univ., Cambridge, MA (United States). Center for the Fundamental Laws of Nature
 Publication Date:
 OSTI Identifier:
 1327308
 Grant/Contract Number:
 FG0291ER40654
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of High Energy Physics (Online)
 Additional Journal Information:
 Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2016; Journal Issue: 1; Journal ID: ISSN 10298479
 Publisher:
 Springer Berlin
 Research Org:
 Harvard Univ., Cambridge, MA (United States)
 Sponsoring Org:
 USDOE
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTRONOMY AND ASTROPHYSICS AdSCFT correspondence; gauge symmetry; black holes; global symmetries