1,713 research outputs found

    Thermodynamic limits to information harvesting by sensory systems

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    In view of the relation between information and thermodynamics we investigate how much information about an external protocol can be stored in the memory of a stochastic measurement device given an energy budget. We consider a layered device with a memory component storing information about the external environment by monitoring the history of a sensory part coupled to the environment. We derive an integral fluctuation theorem for the entropy production and a measure of the information accumulated in the memory device. Its most immediate consequence is that the amount of information is bounded by the average thermodynamic entropy produced by the process. At equilibrium no entropy is produced and therefore the memory device does not add any information about the environment to the sensory component. Consequently, if the system operates at equilibrium the addition of a memory component is superfluous. Such device can be used to model the sensing process of a cell measuring the external concentration of a chemical compound and encoding the measurement in the amount of phosphorylated cytoplasmic proteins.Comment: Revised version: 18 pages, 5 figure

    Gravity Effects on Neutrino Masses in Split Supersymmetry

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    The mass differences and mixing angles of neutrinos can neither be explained by R-Parity violating split supersymmetry nor by flavor blind quantum gravity alone. It is shown that combining both effects leads, within the allowed parameter range, to good agreement with the experimental results. The atmospheric mass is generated by supersymmetry through mixing between neutrinos and neutralinos, while the solar mass is generated by gravity through flavor blind dimension five operators. Maximal atmospheric mixing forces the tangent squared of the solar angle to be equal to 1/2. The scale of the quantum gravity operator is predicted within a 5% error, implying that the reduced Planck scale should lie around the GUT scale. In this way, the model is very predictive and can be tested at future experiments.Comment: 12 pages, 9 figures; In section 3 we extend our discussion about the definition of flavor basis in order to clarify in which basis the Gravity contributions are flavor blind. In the section 4 we add some words to explain why the Gravity contributions will not affect the charged lepton mass matrix; Finally we also fixed some minor typos regarding units or plot label

    Neutrino Masses in Split Supersymmetry

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    We investigate the possibility to generate neutrino masses in the context of Split supersymmetric scenarios where all sfermions are very heavy. All relevant contributions coming from the R-parity violating terms to the neutrino mass matrix up to one-loop level are computed, showing the importance of the Higgs one-loop corrections. We conclude that it is not possible to generate all neutrino masses and mixings in Split SUSY with bilinear R-Parity violating interactions. In the case of Partial Split SUSY the one-loop Higgs contributions are enough to generate the neutrino masses and mixings in agreement with the experiment. In the context of minimal SUSY SU(5) we find new contributions which help us to generate neutrino masses in the case of Split SUSY.Comment: 33 pages, 6 figures, to appear in Physical Review

    Will we observe black holes at LHC?

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    The generalized uncertainty principle, motivated by string theory and non-commutative quantum mechanics, suggests significant modifications to the Hawking temperature and evaporation process of black holes. For extra-dimensional gravity with Planck scale O(TeV), this leads to important changes in the formation and detection of black holes at the the Large Hadron Collider. The number of particles produced in Hawking evaporation decreases substantially. The evaporation ends when the black hole mass is Planck scale, leaving a remnant and a consequent missing energy of order TeV. Furthermore, the minimum energy for black hole formation in collisions is increased, and could even be increased to such an extent that no black holes are formed at LHC energies.Comment: 5 pages, 2 figures. Minor changes to match version to appear in Class. Quant. Gra

    The Inflatino Problem in Supergravity Inflationary Models

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    We consider the potential problems due to the production of inflatinos and gravitinos after inflation. Inflationary models with a single scale set by the microwave background anisotropies have a low enough reheat temperature to avoid problems with the thermal production of gravitinos. Moreover, the nonthermal production of gravitinos has been shown to be sufficiently small if the sector ultimately responsible for supersymmetry breaking is coupled only gravitationally to the inflationary sector. Still, in some models, inflatinos can be created during preheating with a substantial abundance. The main contribution to the gravitino abundance may thus come from their decay into the inflaton, or into its scalar partner, as well as from the inverse processes. We show that this production needs to be strongly suppressed. This suppression can be realized in the simplest scenarios which typically have a sufficiently high inflationary scale.Comment: 18 page

    Uncertainties in limits on TeV-gravity from neutrino-induced showers

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    In models with TeV-scale gravity, ultrahigh energy cosmic rays can generate microscopic black holes in the collision with atmospheric and terrestrial nuclei. It has been proposed that stringent bounds on TeV-scale gravity can be obtained from the absence of neutrino cosmic ray showers mediated by black holes. However, uncertainties in the cross section of black hole formation and, most importantly, large uncertainties in the neutrino flux affects these bounds. As long as the cosmic neutrino flux remains unknown, the non-observation of neutrino induced showers implies less stringent limits than present collider limits.Comment: Changes to match published versio

    Cognitive Gadgets: A provocative but flawed manifesto.

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    The argument against innatism at the heart of Cognitive Gadgets is provocative but premature, and is vitiated by dichotomous thinking, interpretive double standards, and evidence cherry-picking. I illustrate my criticism by addressing the heritability of imitation and mindreading, the relevance of twin studies, and the meaning of cross-cultural differences in theory of mind development. Reaching an integrative understanding of genetic inheritance, plasticity, and learning is a formidable task that demands a more nuanced evolutionary approach

    Rethinking the fast-slow continuum of individual differences

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    The idea that individual differences in behavior and physiology can be partly understood by linking them to a fast-slow continuum of life history strategies has become popular in the evolutionary behavioral sciences. I refer to this approach as the “fast-slow paradigm” of individual differences. The paradigm has generated a substantial amount of research, but has also come increasingly under scrutiny for theoretical, empirical, and methodological reasons. I start by reviewing the basic empirical facts about the fast-slow continuum across species and the main theoretical accounts of its existence. I then discuss the move from the level of species and populations to that of individuals, and the theoretical and empirical complications that follow. I argue that the fast-slow continuum can be a productive heuristic for individual differences; however, the field needs to update its theoretical assumptions, rethink some methodological practices, and explore new approaches and ideas in light of the specific features of the human ecology
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