21,882 research outputs found

    Constraints on Flavored 2d CFT Partition Functions

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    We study the implications of modular invariance on 2d CFT partition functions with abelian or non-abelian currents when chemical potentials for the charges are turned on, i.e. when the partition functions are "flavored". We begin with a new proof of the transformation law for the modular transformation of such partition functions. Then we proceed to apply modular bootstrap techniques to constrain the spectrum of charged states in the theory. We improve previous upper bounds on the state with the greatest "mass-to-charge" ratio in such theories, as well as upper bounds on the weight of the lightest charged state and the charge of the weakest charged state in the theory. We apply the extremal functional method to theories that saturate such bounds, and in several cases we find the resulting prediction for the occupation numbers are precisely integers. Because such theories sometimes do not saturate a bound on the full space of states but do saturate a bound in the neutral sector of states, we find that adding flavor allows the extremal functional method to solve for some partition functions that would not be accessible to it otherwise.Comment: 45 pages, 16 Figures v3: typos corrected, expanded appendix on numeric implementatio

    Model-independent WIMP Scattering Responses and Event Rates: A Mathematica Package for Experimental Analysis

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    The community's reliance on simplified descriptions of WIMP-nucleus interactions reflects the absence of analysis tools that integrate general theories of dark matter with standard treatments of nuclear response functions. To bridge this gap, we have constructed a public-domain Mathematica package for WIMP analyses based on our effective theory formulation. Script inputs are 1) the coefficients of the effective theory, through which one can characterize the low-energy consequences of arbitrary ultraviolet theories of WIMP interactions; and 2) one-body density matrices for commonly used targets, the most compact description of the relevant nuclear physics. The generality of the effective theory expansion guarantees that the script will remain relevant as new ultraviolet theories are explored; the use of density matrices to factor the nuclear physics from the particle physics will allow nuclear structure theorists to update the script as new calculations become available, independent of specific particle-physics contexts. The Mathematica package outputs the resulting response functions (and associated form factors) and also the differential event rate, once a galactic WIMP velocity profile is specified, and thus in its present form provides a complete framework for experimental analysis. The Mathematica script requires no a priori knowledge of the details of the non-relativistic effective field theory or nuclear physics, though the core concepts are reviewed here and in arXiv:1203.3542.Comment: 30+6 page

    Conformal Blocks Beyond the Semi-Classical Limit

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    Black hole microstates and their approximate thermodynamic properties can be studied using heavy-light correlation functions in AdS/CFT. Universal features of these correlators can be extracted from the Virasoro conformal blocks in CFT2, which encapsulate quantum gravitational effects in AdS3. At infinite central charge c, the Virasoro vacuum block provides an avatar of the black hole information paradox in the form of periodic Euclidean-time singularities that must be resolved at finite c. We compute Virasoro blocks in the heavy-light, large c limit, extending our previous results by determining perturbative 1/c corrections. We obtain explicit closed-form expressions for both the `semi-classical' hL2/c2h_L^2 / c^2 and `quantum' hL/c2h_L / c^2 corrections to the vacuum block, and we provide integral formulas for general Virasoro blocks. We comment on the interpretation of our results for thermodynamics, discussing how monodromies in Euclidean time can arise from AdS calculations using `geodesic Witten diagrams'. We expect that only non-perturbative corrections in 1/c can resolve the singularities associated with the information paradox.Comment: 24+7 pages, 5 figures; v2 fixed typo in eq 2.22, added refs; v3 fixed typo

    Nonperturbative Matching Between Equal-Time and Lightcone Quantization

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    We investigate the nonperturbative relation between lightcone (LC) and standard equal-time (ET) quantization in the context of λϕ4\lambda \phi^4 theory in d=2d=2. We discuss the perturbative matching between bare parameters and the failure of its naive nonperturbative extension. We argue that they are nevertheless the same theory nonperturbatively, and that furthermore the nonperturbative map between bare parameters can be extracted from ET perturbation theory via Borel resummation of the mass gap. We test this map by using it to compare physical quantities computed using numerical Hamiltonian truncation methods in ET and LC.Comment: 22+8 pages, 10 figure

    Media Coverage of EPA\u27s Draft Dioxin Reassessment Report

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    Using content analysis, the authors examine the utility of news media in democratic decision making

    Discovering Asymmetric Dark Matter with Anti-Neutrinos

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    We discuss possible signatures of Asymmetric Dark Matter (ADM) through dark matter decays to neutrinos. We specifically focus on scenarios in which the Standard Model (SM) baryon asymmetry is transferred to the dark sector (DS) through higher dimensional operators in chemical equilibrium. In such cases, the dark matter (DM) carries lepton and/or baryon number, and we point out that for a wide range of quantum number assignments, by far the strongest constraints on dark matter decays come from decays to neutrinos through the "neutrino portal" operator HL. Together with the facts that ADM favors lighter DM masses ~ a few GeV and that the decays would lead only to anti-neutrinos and no neutrinos (or vice versa), the detection of such decays at neutrino telescopes would provide compelling evidence for ADM. We discuss current and future bounds on models where the DM decays to neutrinos through operators of dimension <= 6. For dimension 6 operators, the scale suppressing the decay is bounded to be >~ 10^12 - 10^13 GeV.Comment: 20 pages, 1 figur

    Exact Virasoro Blocks from Wilson Lines and Background-Independent Operators

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    Aspects of black hole thermodynamics and information loss can be derived as a consequence of Virasoro symmetry. To bolster the connection between Virasoro conformal blocks and AdS3_3 quantum gravity, we study sl(2)(2) Chern-Simons Wilson line networks and revisit the idea that they compute a variety of CFT2_2 observables, including Virasoro OPE blocks, exactly. We verify this in the semiclassical large central charge limit and to low orders in a perturbative 1/c1/c expansion. Wilson lines connecting the boundary to points in the bulk play a natural role in bulk reconstruction. Because quantum gravity in AdS3_3 is rigidly fixed by Virasoro symmetry, we argue that sl(2)(2) Wilson lines provide building blocks for background independent bulk reconstruction. In particular, we show explicitly that they automatically compute the uniformizing coordinates appropriate to any background state.Comment: V3- Added some references V2- Significantly Expanded Appendix on Regulation; 32+21 page
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