This book focuses on AdS3/CFT2, addressing
different aspects of this correspondence in field theory and in gravity,
including entanglement entropy, higher genus partition function, and
conformal block. Holographic entanglement entropy is an important area
in holographic and quantum information, which implies a deep relation
between geometry and quantum entanglement. In this book, the authors use
holographic entanglement entropy as a tool to investigate
AdS3/CFT2. They study the entanglement entropy
at high temperature in field theory and in holographics, and show that
the results match each other in classical and one-loop order. In the
AdS3/CFT2 system, they examine in detail the
correspondence, exploring the higher genus partition function,
entanglement entropy in a general system and conformal block, and they
find good correspondence in field theory and gravity. The result
strongly supports AdS3/CFT2 correspondence. In
addition, they develop several important techniques in 2d CFT and 3d
gravity, which also offer inspiration for other fields.