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arXiv · 1812.08745

From the Weyl Anomaly to Entropy of Two-Dimensional Boundaries and Defects

Kristan Jensen·Andy O'Bannon·Brandon Robinson·Ronnie Rodgers
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Abstract

We study whether the relations between the Weyl anomaly, entanglement entropy (EE), and thermal entropy of a two-dimensional (2D) conformal field theory (CFT) extend to 2D boundaries of 3D CFTs, or 2D defects of $D \geq 3$ CFTs. The Weyl anomaly of a 2D boundary or defect defines two or three central charges, respectively. One of these, $b$, obeys a c-theorem, as in 2D CFT. For a 2D defect, we show that another, $d_2$, interpreted as the defect's `conformal dimension,' must be non-negative by the Averaged Null Energy Condition (ANEC). We show that the EE of a sphere centered on a planar defect has a logarithmic contribution from the defect fixed by $b$ and $d_2$. Using this and known holographic results, we compute $b$ and $d_2$ for 1/2-BPS surface operators in the maximally supersymmetric (SUSY) 4D and 6D CFTs. The results are consistent with $b$'s c-theorem. Via free field and holographic examples we show that no universal `Cardy formula' relates the central charges to thermal entropy.

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Kristan Jensen, Andy O'Bannon, Brandon Robinson, Ronnie Rodgers. 2018-12-20. From the Weyl Anomaly to Entropy of Two-Dimensional Boundaries and Defects. https://doi.org/10.1103/physrevlett.122.241602

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