The geometry of segmented strings and quantum entanglement

Nyomtatóbarát változatNyomtatóbarát változat
Doctoral school: 
Fizikai Tudományok Doktori Iskola
Péter Pál Lévay
Department of Theoretical Physics
Job title: 
senior research fellow
Academic degree: 
Doctor of Science (DSc)

 Quantum theory and general relativity are comprising our basic theories capable of explaining the microscopic properties of matter on one hand and the large scale structure of spacetime on the other.

In special physical situations we need a unified framework of these basic theories called the quantum theory of gravity where we are also interested in explaining the microscopic structure of spacetime.

A theoretically successful (though experimentally still unproved) candidate for this framework is string theory. A special discretized version of this theory is featuring segmented strings propagating in curved spacetime backgrounds.

If the background is asymptotically anti de Sitter then in order to obtain some insight into the structure of this stringy framework one can apply the so called AdS/CFT correspondence.

This correspondence is holographic, in the sense that it relates a $d$ dimensional quantum gravity theory of the background bulk spacetime to a conformal quantum field theory (CFT)  without gravity living on its $d-1$ asymptotic boundary.

It turns out that in this holographic picture geometrical quantities of the bulk, can be related in a mathematically precise manner to quantities of quantum information and quantum entanglement of the states encapsulating physical situations of the CFT in the  boundary.

Recently it has been shown that when the entangled CFT state is the vacuum (which is holographically dual to the quantum geometry of pure AdS spacetime) the holographic correspondence well-known from the literature can be rephrased in terms of segmented strings in an elegant manner.

The aim of the PhD topic is to explore this segmented string based reformulation for other CFT states via studying excited states of the vacuum, and its associated asymptotically AdS geometries.

Familiarity with the AdS/CFT correspondence and the basics of string theory. Experience in using standard mathematical methods of differential geometry and group theory. Introductory level knowledge of the simplest results of quantum entanglement theory.
Project type: 
PhD project for standard admission