6,103 research outputs found
Commitment and Oblivious Transfer in the Bounded Storage Model with Errors
The bounded storage model restricts the memory of an adversary in a
cryptographic protocol, rather than restricting its computational power, making
information theoretically secure protocols feasible. We present the first
protocols for commitment and oblivious transfer in the bounded storage model
with errors, i.e., the model where the public random sources available to the
two parties are not exactly the same, but instead are only required to have a
small Hamming distance between themselves. Commitment and oblivious transfer
protocols were known previously only for the error-free variant of the bounded
storage model, which is harder to realize
Possible new resonance from - interchannel coupling
We propose and theoretically study a possible new resonance caused by strong
coupling between the Higgs-Higgs and the W_L W_L (Z_L Z_L) scattering channels,
without regard to the intensity of the elastic interaction in either channel at
low energy (that could be weak as in the Standard Model). We expose this
channel-coupling resonance from unitarity and dispersion relations encoded in
the Inverse Amplitude Method, applied to the Electroweak Chiral Lagrangian with
a scalar Higgs.Comment: 4 pages, 7 figure
One-loop and scattering from the Electroweak Chiral Lagrangian with a light Higgs-like scalar
By including the recently discovered Higgs-like scalar in the
Electroweak Chiral Lagrangian, and using the Equivalence Theorem, we carry out
the complete one-loop computation of the elastic scattering amplitude for the
longitudinal components of the gauge bosons at high energy. We also
compute and the inelastic process
, and identify the counterterms needed to cancel
the divergences, namely the well known and chiral parameters plus
three additional ones only superficially treated in the literature because of
their dimension 8. Finally we compute all the partial waves and discuss the
limitations of the one-loop computation due to only approximate unitarity.Comment: 28 pages, 19 plots, 9 Feynman-diagram sets This version revised and
accepted in JHE
Unitarity, analyticity, dispersion relations and resonances in strongly interacting , and scattering
If the Electroweak Symmetry Breaking Sector turns out to be strongly
interacting, the actively investigated effective theory for longitudinal gauge
bosons plus Higgs can be efficiently extended to cover the regime of saturation
of unitarity (where the perturbative expansion breaks down). This is achieved
by dispersion relations, whose subtraction constants and left cut contribution
can be approximately obtained in different ways giving rise to different
unitarization procedures. We illustrate the ideas with the Inverse Amplitude
Method, one version of the N/D method and another improved version of the
K-matrix. In the three cases we get partial waves which are unitary, analytical
with the proper left and right cuts and in some cases poles in the second
Riemann sheet that can be understood as dynamically generated resonances. In
addition they reproduce at Next to Leading Order (NLO) the perturbative
expansion for the five partial waves not vanishing (up to J=2) and they are
renormalization scale () independent. Also the unitarization formalisms
are extended to the coupled channel case. Then we apply the results to the
elastic scattering amplitude for the longitudinal components of the gauge
bosons at high energy. We also compute and the
inelastic process which are coupled to the elastic
channel for custodial isospin . We numerically compare the three methods
for various values of the low-energy couplings and explain the reasons for the
differences found in the partial wave. Then we study the resonances
appearing in the different elastic and coupled channels in terms of the
effective Lagrangian parameters.Comment: 45 pages, 28 figure
Coupling WW, ZZ unitarized amplitudes to in the TeV region
We define and calculate helicity partial-wave amplitudes for processes
linking the Electroweak Symmetry Breaking Sector (EWSBS) to ,
employing (to NLO) the Higgs-EFT (HEFT) extension of the Standard Model and the
Equivalence Theorem, while neglecting all particle masses. The resulting
amplitudes can be useful in the energy regime ().
We also deal with their unitarization so that resonances of the EWSBS can
simultaneously be described in the initial or final states. Our
resulting amplitudes satisfy unitarity, perturbatively in , but for all
values. In this way we improve on the HEFT that fails as interactions
become stronger with growing and provide a natural framework for the decay
of dynamically generated resonances into , and pairs.Comment: 23 pages, 9 figure
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Models and analyses of chromosome evolution
textAt the core of evolutionary biology stands the study of divergence between populations and the formation of new species. This dissertation applies a diverse array of theoretical and statistical approaches to study how chromosomes evolve. In the first chapter, I build models that predict the amount of neutral genetic variation in chromosomal inversions involved in local adaptation, providing a foundation for future studies on the role of these rearrangements in population divergence. In the second chapter, I use a large dataset of the geographic variation in frequency of a chromosomal inversion to infer natural selection and non-random mating, revealing that this inversion could be implicated in strong reproductive isolation between subpopulations of a single species. In the third chapter, I use coalescent models for recombining sex chromosomes coupled with approximate Bayesian computation to estimate the recombination rate between X and Y chromosomes in European tree frogs. This novel approach allows me to infer a rate so low that would have been hard to detect with empirical methods. In the fourth chapter, I study the theoretical conditions that favor the evolution of a chromosome fusion that reduces recombination between locally adapted alleles.Ecology, Evolution and Behavio
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