Ahmad Jamali Hafshejani

arXiv2020

Mass corrections to the DGLAP equations

We propose a mass-dependent MOM scheme to renormalize UV divergence of unpolarized PDFs at one-loop order. This approach which is based on a once subtracted dispersion relation does not need any regulator. The overall counterterms are obtained from the imaginary part of large transverse momentum region in loop integrals. The mass-dependent characteristic of the scheme yields to mass-dependent splitting functions for the DGLAP evolution equations. While the flavor number is fixed at any renormalization scale, the decoupling theorem is automatically imposed by the mass-dependent splitting functions. The required symmetries are also automatically respected by our prescription.

hep-ph↗

arXiv2018

Unbalanced Stückelberg Holographic Superconductors with Backreaction

We numerically investigate some properties of unbalanced Stückelberg holographic superconductors, by considering backreaction effects of fields on the background geometry. More precisely, we study the impacts of the chemical potential mismatch and Stückelberg mechanism on the condensation and conductivity types (electrical, spin, mixed, thermo-electric, thermo-spin and thermal conductivity). Our results show that the Stückelberg's model parameters $C_α$ and $α$ not only have significant impacts on the phase transition, but also affect the conductivity pseudo-gap and the strength of conductivity fluctuations. Moreover, the effects of these parameters on a system will be gradually reduced as the imbalance grows. We also find that the influence of $α$ on the amplitude of conductivity fluctuations depends on the magnitude of the both $C_α$ and $δμ/μ$ in the electric and thermal conductivity cases. This results in that increasing $α$ can damp the conductivity fluctuations of an unbalanced system in contrast to balanced ones.

hep-th↗