An Introduction to Entanglement Measures in Conformal Field Theories and AdS/CFT

Shinsei Ryu, Tadashi Takayanagi

A holographic derivation of the entanglement entropy in quantum (conformal) field theories is proposed from anti-de Sitter/conformal field theory (AdS/CFT) correspondence. We argue that the entanglement entropy in d + 1 dimensional conformal field theories can be obtained from the area of d dimensional minimal surfaces in AdS(d+2), analogous to the Bekenstein-Hawking formula for black hole entropy. We show that our proposal agrees perfectly with the entanglement entropy in 2D CFT when applied to AdS(3). We also compare the entropy computed in AdS(5)XS(5) with that of the free N=4 super Yang-Mills theory.

Stefan Hollands, Ko Sanders

Stefan Hollands, Ko Sanders

Koushik Bar, Supervisors Dr. Sunandan Gangopadhyay, Prasanta Kumar Panigrahi

These features the study of conformal quantum field theories, in dimensions greater than two dimension and very special case of two dimensions. Over the last two decades, the understanding and mathematical formulation of such theories has developed to a very mature state, and conformal field theory (CFT) has in uenced both mathematics and physics. As such, it can be considered a prototype example for a constructive interplay between these two subjects. The main feature of a conformal field theory is the invariance under conformal transformations. We also review the development in the field of entanglement entropy, the holographic aspect of it, and the AdS/CFT conjuncture. Describe the Ruy-Takayangai conjecture of Entanglement Entropy and study the reconstruction of the AdS metric using the same for two different case, which are, 1+1 CFT in Infinite Line, and 1+1 CFT in compact circle.

Masahiro Nozaki A, Tokiro Numasawa, Andrea Prudenziati +1 more

We study the dynamics of entanglement entropy for weakly excited states in conformal field theories by using anti-de Sitter/conformal field theory (AdS/CFT). This is aimed at a first step to finding a counterpart of the Einstein equation in CFT language. In particular, we point out that the entanglement entropy satisfies differential equations that directly correspond to the Einstein equation in several setups of AdS/CFT. We also define a quantity called entanglement density in higher dimensional field theories and study its dynamical property for weakly excited states in conformal field theories.

Pablo Bueno, Horacio Casini, William Witczak‐Krempa