Classical Tensors and Quantum Entanglement I: Pure States

The geometrical description of a Hilbert space asociated with a quantum system considers a Hermitian tensor to describe the scalar inner product of vectors which are now described by vector fields. The real part of this tensor represents a flat Riemannian metric tensor while the imaginary part represents a symplectic two-form. The immersion of classical manifolds in the complex projective space associated with the Hilbert space allows to pull-back tensor fields related to previous ones, via the immersion map. This makes available, on these selected manifolds of states, methods of usual Riemannian and symplectic geometry. Here we consider these pulled-back tensor fields when the immersed submanifold contains separable states or entangled states. Geometrical tensors are shown to encode some properties of these states. These results are not unrelated with criteria already available in the literature. We explicitly deal with some of these relations.Comment: 16 pages, 1 figure, to appear in Int. J. Geom. Meth. Mod. Phy

Children's views of death

Death is very much a part of the everyday thoughts of children. It is part of the games they play, the stories they hear, and the videos they watch. Sadly, for some children it is also part of their everyday lives—their lived experience in the face of a life-threatening illness, war, violence, or natural disaster. Starting from the position that a child is a sentient, social, emotional, spiritual being embodied in a biological organism we look at how children’s views develop, and how they are manifest in art, play, and conversations with family, friends, and professionals. We see children as active agents in their worlds—interpreting the behaviour of others and acting on the basis of those interpretations. Children see, sense, and notice, and correspondingly, register and make inferences from what they observe inside and outside of themselves. We attend not only to age and stage of development, but also to the dynamic relationship between age, stage, and experience as they come to bear on the children and their worlds at given points in time. Working from this perspective we explore children’s views of death and dying in a variety of situations, from a variety of perspectives—cognitive, cultural, social, and emotional—as a first step in developing guidance for talking with children who are themselves ill and dying, and their siblings. We address three questions and offers suggestions for talking with ill children and their siblings about death: 1. What do children know and understand about death and dying? / 2. Where do children’s ideas about death and dying come from? / 3. How should we address their questions and concerns on this most fundamental question of human existence? The chapter draws on an extensive review of the literature on well and ill children’s views of death as well as the co-authors’ ethnographically based research with ill children, their parents, siblings, and clinicians involved in their care and treatment; highlighting the social nature of death and dyin

Dos cirurgians estrangers a la ciutat de Lleida

Relatem alguns aspectes de la vida de dos cirurgians del segle XVII, que van fer cap a la ciutat de Lleida procedents de l’estranger. Es tracta del gascó Ramon Cardellac i del sicilià Alfonso Mauro. El primer, s’hi va arrelar casant-se amb dos lleidatanes i hi va morir exercint la cirurgia a l’hospital del morbo que es va construir a la perifèria de la ciutat durant la pesta de 1652 i el sicilià, amb més sort, s’hi va enriquir uns anys després, encara que també hi va morir a començaments de 1660