In previous work [1] new bounded coherent states construction, based on a Keldysh conjecture, was introduced. As was shown in [1] the particular group structure arising from the model leads to new symmetry transformations for the coherent states system. As was shown, the emergent new symmetry transformation is reminiscent of the Bogoliubov ones and was successfully applied to describe an excitonic system showing that is intrinsically related to the stability and its general physical behavior. The group theoretical structure of the model permits to analyze its thermal properties in theoretical frameworks that arise as a consequence of the definition of the squeezed-coherent states as transformed vacua under the automorphism group of the commutation relations, as the thermofield dynamics case given by Umezawa and other similar developments [5]. On the other hand, the idea of a possible Bose--Einstein condensation (BEC) of excitons in semiconductors has attracted the attention of both experimentalists and theoreticians for more than three decades being one of the main questions what happens with the influence of non zero temperature in the case that such condensation really exists [2]. In this paper we considered the theoretical treatment of the excitonic behaviour by mean a new coherent state construction of bounded states in a quantum field theoretical context.In previous work [1] new bounded coherent states construction, based on a Keldysh conjecture, was introduced. As was shown in [1] the particular group structure arising from the model leads to new symmetry transformations for the coherent states system. As was shown, the emergent new symmetry transformation is reminiscent of the Bogoliubov ones and was successfully applied to describe an excitonic system showing that is intrinsically related to the stability and its general physical behavior. The group theoretical structure of the model permits to analyze its thermal properties in theoretical frameworks that arise as a consequence of the definition of the squeezed-coherent states as transformed vacua under the automorphism group of the commutation relations, as the thermofield dynamics case given by Umezawa and other similar developments [5]. On the other hand, the idea of a possible Bose--Einstein condensation (BEC) of excitons in semiconductors has attracted the attention of both experimentalists and theoreticians for more than three decades being one of the main questions what happens with the influence of non zero temperature in the case that such condensation really exists [2]. In this paper we considered the theoretical treatment of the excitonic behaviour by mean a new coherent state construction of bounded states in a quantum field theoretical context.

arXiv:1408.6685Aug 28, 20140 citations

Bounded coherent states and excitonic systems

Diego Julio Cirilo-Lombardo

New bounded coherent state construction, based in a Keldysh conjecture, is presented. The particular group structure arising from the model leads a new symmetry transformations for the coherent state system. The emergent new symmetry transformations are reminiscent of the Bogoliubov ones. This construction is applied to describe an excitonic system. We discuss how the symmetry of these transformations is intrinsically related with the stability and the behavior of the physical systems as in the excitonic case.New bounded coherent state construction, based in a Keldysh conjecture, is presented. The particular group structure arising from the model leads a new symmetry transformations for the coherent state system. The emergent new symmetry transformations are reminiscent of the Bogoliubov ones. This construction is applied to describe an excitonic system. We discuss how the symmetry of these transformations is intrinsically related with the stability and the behavior of the physical systems as in the excitonic case.

Physics of Particles and Nuclei LettersJul 1, 20143 citations

Higher order coherence of exciton-polariton condensates

Tomoyuki Horikiri, P. Schwendimann, A. Quattropani +3 more

The second- and third-order coherence functions ${g}^{(n)}(0)$ ( $n=2$ and 3) of an exciton-polariton condensate are measured and compared to the theory. Contrary to an ideal photon laser, deviation from unity in the second- and third-order coherence functions is observed, thus showing a bunching effect, but not the characteristics of a standard thermal state with ${g}^{(n)}(0)=n!$ . The increase in bunching with the order of the coherence function, ${g}^{(3)}(0)>{g}^{(2)}(0)>1$ , indicates that the polariton condensate is different from a coherent state, a number state, or a thermal state. The measurement of third-order coherence has the advantage, compared to the second-order one, that the difference between a thermal state and a coherent state is more pronounced. The experimental results are in agreement with the theoretical model where polariton-polariton and polariton-phonon interactions are responsible for the loss of temporal coherence.The second- and third-order coherence functions ${g}^{(n)}(0)$ ($n=2$ and 3) of an exciton-polariton condensate are measured and compared to the theory. Contrary to an ideal photon laser, deviation from unity in the second- and third-order coherence functions is observed, thus showing a bunching effect, but not the characteristics of a standard thermal state with ${g}^{(n)}(0)=n!$. The increase in bunching with the order of the coherence function, ${g}^{(3)}(0)>{g}^{(2)}(0)>1$, indicates that the polariton condensate is different from a coherent state, a number state, or a thermal state. The measurement of third-order coherence has the advantage, compared to the second-order one, that the difference between a thermal state and a coherent state is more pronounced. The experimental results are in agreement with the theoretical model where polariton-polariton and polariton-phonon interactions are responsible for the loss of temporal coherence.

arXiv:0910.2978Physical Review BJan 25, 201067 citations

Coherent states and phase transitions in a high-density exciton system

V. A. Moskalenko

NASA STI/Recon Technical Report AJan 1, 19850 citations

The second- and third-order coherence functions

{g}^{(n)}(0)

(

n=2

and 3) of an exciton-polariton condensate are measured and compared to the theory. Contrary to an ideal photon laser, deviation from unity in the second- and third-order coherence functions is observed, thus showing a bunching effect, but not the characteristics of a standard thermal state with

{g}^{(n)}(0)=n!

. The increase in bunching with the order of the coherence function,

{g}^{(3)}(0)>{g}^{(2)}(0)>1

, indicates that the polariton condensate is different from a coherent state, a number state, or a thermal state. The measurement of third-order coherence has the advantage, compared to the second-order one, that the difference between a thermal state and a coherent state is more pronounced. The experimental results are in agreement with the theoretical model where polariton-polariton and polariton-phonon interactions are responsible for the loss of temporal coherence.