Year: 2026
Type: article
Abstract: A bstract The strongly-coupled 3-dimensional theory, holographically dual to black branes at fixed chemical potential μ and temperature T ≪ μ is considered in AdS 4 Einstein-Maxwell theory. The retarded Green’s functions at frequency ω is calculated using holography in the regime ω , T ≪ μ but otherwise arbitrary. When the transverse space has finite volume, there is a non-zero energy scale E gap , scaling as 1/ μ for large μ , below which quantum-gravitational corrections due to the fluctuations of the nearly-gapless Schwarzian modes become important. Such corrections to the retarded Green’s function are calculated at different relative values of ω , T , and E gap . The ω → 0 limit is used to define the shear viscosity η . As the temperature is lowered below μ , quantum corrections are found to increase the value of η with respect to its semiclassical value. The quantum-corrected result for η diverges as $$ \sqrt{{\mathrm{E}}_{\mathrm{gap}}/T} $$ E gap / T at T ≪ E gap , in accord with corresponding results for the absorption cross section. The quantum result for the ratio η / s , where s is the entropy density, dips below the semiclassical limit of 1/4 π when E gap ≪ T ≪ μ , then turns back to increase towards lower temperatures, and finally diverges at temperatures much below E gap .
Source: Journal of High Energy Physics
Institutions: University of Crete, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Laboratoire AstroParticule et Cosmologie, Sorbonne Paris Cité, Institut National de Physique Nucléaire et de Physique des Particules, Institut de Recherche sur les Lois Fondamentales de l'Univers, King's College London, École Polytechnique, Centre de Physique Théorique, Institut Polytechnique de Paris
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7169580900