Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/6208
Title: Torsional instanton effects in quantum gravity
Authors: Kaul, Romesh K.
Sengupta, Sandipan
Issue Date: 29-Dec-2014
Publisher: American Physical Society
Citation: Physical Review D, 2014, Vol. 90, p124081
Abstract: We show that in the first-order gravity theory coupled to axions the instanton number of the Giddings-Strominger wormhole can be interpreted as the Nieh-Yan topological index. The axion charge of the baby universes is quantized in terms of the Nieh-Yan integers. Tunneling between universes of different Nieh-Yan charges implies a nonperturbative vacuum state. The associated topological vacuum angle can be identified with the Barbero-Immirzi parameter.
Description: Open Access
URI: http://hdl.handle.net/2289/6208
ISSN: 1550-7998
1550-2368(Online)
Alternative Location: http://arxiv.org/abs/1411.4793
http://dx.doi.org/10.1103/PhysRevD.90.124081
http://adsabs.harvard.edu/abs/2014PhRvD..90l4081K
Copyright: 2014 American Physical society
Appears in Collections:Research Papers (TP)

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