麻豆社区

How do we define a subsystem in quantum gravity?  This is an essential prerequisite to formulating a notion of quantum information in gravitational theories.   In this talk we will answer this question in a toy model of quantum gravity given by topological string theory. 

We explain how a subsystem of  closed strings is given by open strings which end on the at large N number of D branes that play the role of a stringy entangling surface.   The entangling of these open strings reproduces the original closed strings via a geometric transition, in which  ``entanglement branes" dissolve into closed string flux.   This geometric transition represents a type of local holography closely related to Gopakuma-Vafa duality, and therefore employs the same worldsheet mechanism.    The factorization of closed  strings into open strings can be mapped to  the factorization of closed Wilson loops into open Wilson lines in large N Chern Simons theory.    We explain how these subregion Wilson lines are described by an open string operator algebra, which provides an algebraic definition of a subsystem in string theory.    Finally, we show how the geometric transition of entanglement branes is implemented by a quantum trace on the open string algebra.