Spontaneous magnetization of quantum XYXY spin model in joint presence of quenched and annealed disorder

We investigate equilibrium statistical properties of the quantum XY spin-1/2 model in an external magnetic field when the interaction and field parts are subjected to quenched or/and annealed disorder. The randomness present in the system are termed annealed or quenched depending on the relation between two different time scales - the time scale associated with the equilibriation of the randomness and the time of observation. Within a mean-field framework, we study the effects of disorders on spontaneous magnetization, both by perturbative and numerical techniques. Our primary interest is to understand the differences between quenched and annealed cases, and also to investigate the interplay when both of them are present in a system. We observe in particular that when interaction and field terms are respectively quenched and annealed, critical temperature for the system to magnetize in the direction parallel to the applied field does not depend on any of the disorders. Further, an annealed disordered interaction neither affects the magnetizations nor the critical temperatures. We carry out a comparative study of the different combinations of the disorders in the interaction and field terms, and point out their generic features.Comment: 9 pages, 2 figures, 1 tabl

Reclaiming and Asserting Human Rights in Testimonio Genre:: A Critical Study

The relationship between the stories embedded in literature and human rights has been replete with paramount importance. The narrative genre that has explored the confluence of human rights and literature is testimonio. Testimonio is the emotionally overcharged record of the self because it documents pain and suffering, humiliation and oppression. Testimonio is a medium through which the author expresses his/her experiences and at the same time works as an agent of articulating the collective experience. Testimonio narratives of collective suffering and emancipation urge readers to locate and analyse the situation of the oppressed community. The writers act as witnesses who reveal the conspiracies and mechanism of the perpetrators of violence, thereby initiating advocacy and activism on behalf of the oppressed people. Originated in Latin American countries the narrative genre testimonio articulates numerous struggles to restore human rights. The paper explores how the testimonio genre can be employed as a powerful narrative to initiate social change