## Abstract

QED with a large number N of massless fermionic degrees of freedom has a conformal phase in a range of space-time dimensions. We use a large N diagrammatic approach to calculate the leading corrections to C_{T} , the coefficient of the two-point function of the stress-energy tensor, and C_{J} , the coefficient of the two-point function of the global symmetry current. We present explicit formulae as a function of d and check them versus the expectations in 2 and 4 − ϵ dimensions. Using our results in higher even dimensions we find a concise formula for C_{T} of the conformal Maxwell theory with higher derivative action Fμν(−∇2)d2−2Fμν. In d = 3, QED has a topological symmetry current, and we calculate the correction to its two-point function coefficient, C_{J} ^{top}. We also show that some RG flows involving QED in d = 3 obey C_{T} ^{UV} > C_{T} ^{IR} and discuss possible implications of this inequality for the symmetry breaking at small values of N.

Original language | English (US) |
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Article number | 156 |

Journal | Journal of High Energy Physics |

Volume | 2016 |

Issue number | 8 |

DOIs | |

State | Published - Aug 1 2016 |

## All Science Journal Classification (ASJC) codes

- Nuclear and High Energy Physics

## Keywords

- 1/N Expansion
- Renormalization Group