用AdS/CFT對偶研究強相互作用系統中的相結構

Abstract

我們計畫用弦理論/場論對偶的方法來研究量子色動力學中的相變結構。近年來，人們發現量子色動力學在高密度下的狀態總是手征對稱破缺的，包括色味同步相和色超導相。此外，重離子對撞機和大強子對撞機在中離子實驗的結果顯示在高溫和高密度條件下，強耦合的夸克-膠子離子態行為很像理想流體。這些在量子色動力學高密度條件下豐富的相結構促使我們去研究強相互作用下的量子色動力學。 一些建立在弦理論/場論對偶方法上的模型已經被用來研究量子色動力學的相結構，但還沒有任何已知的模型可以產生出完整的量子色動力學像圖。我們計畫通過研究已有的模型去構造一個更加完備的現象學模型，使得這個模型可以儘量產生出完整的量子色動力學的相圖。更進一步的計畫是根據弦理論中的膜構建方法，把適當的膜嵌入一個弦理論時空中，從而構造出一個從基礎理論得到的模型，並用此模型來研究量子色動力學中的各種現象。

We are going to study QCD phase diagram by the method of AdS/CFT duality, i.e. AdS/QCD. Rencently, it is found that the new phases appear at high density with always chiral symmetry breaking (χSB) phases, namely a color-flavor-locking (CFL) phase and a color-superconductor (CS). Furthermore, the results of heavy ion experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) discovered that, at high density and high temperature, the strongly coupled quark-gluon plasma (QGP) is like a perfect fluid. The rich phase structure in the high density regime of QCD encourages us to study the strongly interacting QCD. Several models have been built in terms of AdS/CFT duality to study the phase structure of QCD, but none of the known models can reproduce the full QCD phase diagram. We are going to study the existing models and combine them together to get a bottom-up model, which could produce the QCD phase diagram as precise as possible. Then the more challenge job is to build a top-down model from brane configurations in string theory by using deformed string backgrounds with proper probe branes, and use the model to study the various properties in QCD.