RESUMEN
Complete information on the equilibrium behavior and dynamics of quantum field theory (QFT) is provided by multipoint correlation functions. However, their theoretical calculation is a challenging problem, even for exactly solvable models. This has recently become an experimentally relevant problem, due to progress in cold-atom experiments simulating QFT models and directly measuring higher order correlations. Here we compute correlation functions of the quantum sine-Gordon model, a prototype integrable model of central interest from both theoretical and experimental points of view. Building upon the so-called truncated conformal space approach, we numerically construct higher order correlations in a system of finite size in various physical states of experimental relevance, both in and out of equilibrium. We measure deviations from Gaussianity due to the presence of interaction and analyze their dependence on temperature, explaining the experimentally observed crossover between Gaussian and non-Gaussian regimes. We find that correlations of excited states are markedly different from the thermal case, which can be explained by the integrability of the system. We also study dynamics after a quench, observing the effects of the interaction on the time evolution of correlation functions, their spatial dependence, and their non-Gaussianity as measured by the kurtosis.
RESUMEN
We propose a boundary thermodynamic Bethe ansatz calculation technique to obtain the Loschmidt echo and the statistics of the work done when a global quantum quench is performed on an integrable quantum field theory. We derive an analytic expression for the lowest edge of the probability density function and find that it exhibits universal features, in the sense that its scaling form depends only on the statistics of excitations. We perform numerical calculations on the sinh-Gordon model, a deformation of the free boson theory, and we obtain that by turning on the interaction the density function develops fermionic properties. The calculations are facilitated by a previously unnoticed property of the thermodynamic Bethe ansatz construction.
RESUMEN
The p53 suppressor gene is the most frequently altered gene in solid human malignancies. It is located on the short arm of chromosome 17 in the region 17p13 and encodes a 53kD nuclear phosphoprotein containing 393 amino acids with specific DNA binding properties and a short life span. The wild p53 protein has been classified as a tumoral suppression gene with a determining role in controlling cellular proliferation and differentiation and can be inactivated through mutation in the protein sequence encoding the gene, leading to neoplastic transformation. In this study we analyzed the expression of p53 protein in a variety of salivary gland malignant tumors fixed in formalin and included in paraffin, using the method of immunohistochemical coloring with the anti-p53 DO-7 antibody. The evaluation of the immunoreactivity with p53 proved a significantly more intense coloring in salivary gland high-grade malignant tumors and the observed immunomarking of over 50% of the tumoral cells is correlated with the weak differentiation of the tumors, giving a predictive factor for the evolution of the disease.
