18.04.2013

Title:
Relationships between entanglement and phase transitions in an exciton-polariton BEC confined in a nanocavity. 

Abstract
Recently, the two-dimensional nanocavity exciton-polariton system confined in semiconductor nanocavities has emerge as a promising alternative of Bose-Einstein Condesation (BEC). The strong quantum correlations presents in this system, make it an unique candidate for studying entanglement and quantum phase transitions —qualitative changes in the ground state properties—. In this work, we review previous evidence, obtained by us, in the phase transitions of a finite exciton-polariton system. First, by using a BCS wave function to compute the ground state energy of N excitons  without the photonic field, a crossover from the high-density electron-hole phase to the BCS excitonic phase is found, at a density which is roughly four times the close-packing density of excitons. Second, by means of a self-consistent procedure with a trial function composed of a coherent photon field and a BCS function for the electron-hole pairs, we obtain the scaling of the critical temperature with the number of polaritons. Using the method proposed by Comte and Nozieres, and generalizing it, we will expect to find a interpolating function between the distinct phases and provide clues about the relationship between the phase diagram and the entanglement in this system.





14.04.2013

Señores de la Escuela de Física Matemática.
Reciban un cordial saludo.
Acontinuación escribo el título y el resumen para el póster.

Tiltle: 
Relationships between phase transitions and entanglement in a polaritons-excitons BEC confined.
Abstract:
Recently two-dimensional nanocavity exciton-polariton system has emerge as a promising alternative of Bose-Einstein Condesation (BEC). The strong quantum correlations presents in this system, make it a unique candidate for studying entanglement and quantum phase transitions —qualitative change in the ground state properties—. In this work, we review previous evidence, obtained by us, in the phase transitions of a finite exciton-polariton system. First, by using a BCS wave function to compute the ground state energy of N excitons —i.e., without the photonic field—, a crossover from the high-density electron-hole phase to the BCS excitonic phase is found, at a density which is roughly four times the close-packing density of excitons. 
Second, by means of a self-consistent procedure with a trial function composed of a coherent photon field and a BCS function for the electron-hole pairs, we obtain the scaling of the critical temperature with the number of polaritons. Using the method proposed by Comte and Nozieres, and generalizing it, we will expect to find a interpolating function between the distinct phases and provide clues about the relationship between the phase diagram and the entanglement in this system.