Research in String Theory and Holography

点击翻译按钮获取中文摘要

This award funds the research activities of Professor Vadim Kaplunovsky at the University of Texas at Austin. His work focuses on several aspects of string theory -- which unifies gravity with the other fundamental forces of nature (strong, weak, and electromagnetic). String theory has an unusual property - it contains something called "holographic dualities", which relate theories in many-body quantum systems (ranging from quark-gluon plasma to superconductors) to theories of gravity in higher dimensional spaces. These dualities, since they relate to very different systems, allow calculations in one system to give results in the other. Professor Kaplunovsky studies the duality between forms of super-dense nuclear matter and models with crystal-like structures, as well as the duality between models of gravity in highly curved spaces with strongly interacting particle physics models. He also studies string theories which are dual to each other. All these projects are deeply connected to other aspects of string theory as well as to particle physics, nuclear physics, and condensed matter. To enhance the broader impact of his research, Professor Kaplunovsky will give a series of talks to high-school students about hot issues of modern physics (which alas are not even mentioned in a regular curriculum). The subjects may involve fundamental particles, cosmology, or anything else the students may be interested in. Prof. Kaplunovsky will also give a series of more advanced lectures about theoretical physics to the undergraduate students at the University of Texas and at other universities in the US and overseas.Prof. Kaplunovsky's research focuses on several issues of string theory and holographic QCD. One project is about infinite crystals of YM instantons -- which 'live' in 4+1 dimensions (where they act as particles) but may form lower-dimensional lattices in external potentials. There are many types of such crystals, with different lattice geometries and/or different patterns of instantons' isospin orientations. The project focuses on surveying such crystals and the phase transitions between them, especially the transitions which change the dimensionality of the lattice (3D-4D, or 2D-3D, or 1D-2D). Another project focuses on leading order (in alpha') stringy corrections to the hadron spectra in high-curvature holographic QCD models with O(1) 't Hooft couplings. A related issue concerns stringy corrections to the short-distance nuclear forces in models where the dual baryons looks like string stars rather than instantons. The third project is about M theory duals of the heterotic orbifolds, which seem to give paradoxical results, and he hopes to come up with a solution to these puzzles.