21,882 research outputs found
Constraints on Flavored 2d CFT Partition Functions
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
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
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'
and `quantum' 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
We investigate the nonperturbative relation between lightcone (LC) and
standard equal-time (ET) quantization in the context of theory
in . 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
Using content analysis, the authors examine the utility of news media in democratic decision making
Discovering Asymmetric Dark Matter with Anti-Neutrinos
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
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 AdS quantum gravity, we study sl Chern-Simons
Wilson line networks and revisit the idea that they compute a variety of
CFT observables, including Virasoro OPE blocks, exactly. We verify this in
the semiclassical large central charge limit and to low orders in a
perturbative expansion.
Wilson lines connecting the boundary to points in the bulk play a natural
role in bulk reconstruction. Because quantum gravity in AdS is rigidly
fixed by Virasoro symmetry, we argue that sl 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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