The analytic structure of the fixed charge expansion

Autor: Oleg Antipin, Jahmall Bersini, Francesco Sannino, Matías Torres
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of High Energy Physics, Vol 2022, Iss 6, Pp 1-29 (2022)
Druh dokumentu: article
ISSN: 1029-8479
DOI: 10.1007/JHEP06(2022)041
Popis: Abstract We investigate the analytic properties of the fixed charge expansion for a number of conformal field theories in different space-time dimensions. The models investigated here are O(N) and QED 3. We show that in d = 3 − ϵ dimensions the contribution to the O(N) fixed charge Q conformal dimensions obtained in the double scaling limit of large charge and vanishing ϵ is non-Borel summable, doubly factorial divergent, and with order Q $$ \sqrt{Q} $$ optimal truncation order. By using resurgence techniques we show that the singularities in the Borel plane are related to worldline instantons that were discovered in the other double scaling limit of large Q and N of ref. [1]. In d = 4 − ϵ dimensions the story changes since in the same large Q and small E regime the next order corrections to the scaling dimensions lead to a convergent series. The resummed series displays a new branch cut singularity which is relevant for the stability of the O(N) large charge sector for negative ϵ. Although the QED 3 model shares the same large charge behaviour of the O(N) model, we discover that at leading order in the large number of matter field expansion the large charge scaling dimensions are Borel summable, single factorial divergent, and with order Q optimal truncation order.
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