|Description||2018 Fall Graduate Colloquium Series|
Holographic Complexity: A Tool to Probe the Property of Reduced Fidelity Susceptibility
Quantum information theory and holography play central roles in our understanding of quantum gravity. Exploring their connections will lead to profound effects on our understanding of modern physics and is, thus, a key challenge for present theory and experiments. In this paper, we investigate a recent conjectured connection between reduced fidelity susceptibility and holographic complexity (denoted as the RFS/HC duality). We give a quantitative proof of the duality by performing both holographic and field theoretical computations. In addition, holographic complexity in AdS2þ1 are explored and several important properties are obtained. These properties allow us, via the RFS/HC duality, to obtain a set of remarkable identities of the reduced fidelity susceptibility, which may have significant implications for our understanding of it. Moreover, utilizing these properties and the recent proposed diagnostic tool based on the fidelity susceptibility, experimental verification of the RFS/HC duality becomes possible.
 Gan W C, et al. Physical Review D 96(2): 026008 (2017).
An Effective String Theory Description of the Pomeron
Based on analysis of the scattering S-matrix and its properties, the Regge theory was proposed to describe hadron-hadron scattering at high energies before the advent of Quantum Chromodynamics (QCD), and correspondingly gave rise to a Reggeon (the pole in the partial wave in t-channel of the scattering process) concept as the mediator of strong interaction. The Reggeon approach was successful in explaining a great number of experimental data corresponding to hadron interaction at high energies. However, when new experimental data was available, it was discovered that the experimental total cross-section violates the predictions of Regge theory, thus limiting the applications of this formalism to relatively lower energy region. To understand new experimental measurements in the higher energy regime, a new exchange theory was eventually proposed and its mediator is called Pomeron (a Regge trajectory consisting a family of particles with increasing spin), which has vacuum quantum numbers. A number of descriptions of the Pomeron in the context of S-matrix Theory and Quantum Field Theory already exist in the literature. In this talk, we revisit the description of the Pomeron within the Effective String Theory of QCD. By means of a string duality relation, it is shown how the static potential maps onto the high-energy scattering amplitude that exhibits the Pomeron behavior. The stringy description also allows for an Odderon (consisting of three Reggeized gluons) that only vanishes in critical dimension.
Reference: Dmitri Kharzeev, Edward Shuryak, and Ismail Zahed, Higher order string effects and the properties of the Pomeron, Phys. Rev. D 97, 016008 (2018): https://doi.org/10.1103/PhysRevD.97.016008
For more information contact: Dr. Howard Lee, 254-710-2277