641,631 research outputs found
Amalgamating players, symmetry and the Banzhaf value
We suggest new characterizations of the Banzhaf value without the symmetry axiom, which reveal that the characterizations by Lehrer (1988, International Journal of Game Theory 17, 89-99) and Nowak (1997, International Journal of Game Theory 26, 127-141) as well as most of the characterizations by Casajus (2010, Theory and De- cision, forthcoming) are redundant. Further, we explore symmetry implications of Lehrer's 2-efficiency axiom.Banzhaf value, amalgamation, symmetry, 2-efficiency
An Accelerating Universe without Lambda: Delta~Gravity Using Monte Carlo
A gravitational field model based on two symmetric tensors, and
, is studied, using a Markov Chain Monte Carlo (MCMC)
analysis with the most updated catalog of SN-Ia. In this model, new matter
fields are added to the original matter fields, motivated by an additional
symmetry (~symmetry). We call them matter
fields. This theory predicts an accelerating Universe without the need to
introduce a cosmological constant by hand in the equations. We
obtained a very good fit to the SN-Ia Data, and with this, we found the two
free parameters of the theory called and . With these values, we have
fixed all the degrees of freedom in the model. The last local value
measurement is in tension with the CMB Data from Planck. Based on an absolute
magnitude for the SN, Delta Gravity finds to be km/(s Mpc). This value is in concordance with the last measurement of the
local value, km/(s Mpc).Comment: latex, 27 pages,15 figure
Solving CFTs with Weakly Broken Higher Spin Symmetry
The method of large spin perturbation theory allows to analyse conformal
field theories (CFT) by turning the crossing equations into an algebraic
problem. We apply this method to a generic CFT with weakly broken higher spin
(HS) symmetry, to the first non-trivial order in the breaking parameter. We
show that the spectrum of broken currents, for any value of the spin, follows
from crossing symmetry. After discussing a generic model of a single scalar
field, we focus on vector models with global symmetry. We rediscover the
spectrum of several models, including the Wilson-Fisher model around
four dimensions, the large model in and cubic models around six
dimensions, not necessarily unitary. We also discuss models where the
fundamental field is not part of the spectrum. Examples of this are weakly
coupled gauge theories and our method gives an on-shell gauge invariant way to
study them. At first order in the coupling constant we show that again the
spectrum follows from crossing symmetry, to all values of the spin. Our method
provides an alternative to usual perturbation theory without any reference to a
Lagrangian.Comment: 30 pages,v2:typos correcte
Superconducting 2D system with lifted spin degeneracy: Mixed singlet-triplet state
Motivated by recent experimental findings, we have developed a theory of the
superconducting state for 2D metals without inversion symmetry modeling the
geometry of a surface superconducting layer in a field-effect-transistor or
near the boundary doped by adsorbed ions. In such systems the two-fold spin
degeneracy is lifted by spin-orbit interaction, and singlet and triplet
pairings are mixed in the wave function of the Cooper pairs. As a result, spin
magnetic susceptibility becomes anisotropic and Knight shift retains finite and
rather high value at T=0.Comment: 5 pages, no figure
Lattice regularization of chiral gauge theories to all orders of perturbation theory
In the framework of perturbation theory, it is possible to put chiral gauge
theories on the lattice without violating the gauge symmetry or other
fundamental principles, provided the fermion representation of the gauge group
is anomaly-free. The basic elements of this construction (which starts from the
Ginsparg-Wilson relation) are briefly recalled and the exact cancellation of
the gauge anomaly, at any fixed value of the lattice spacing and for any
compact gauge group, is then proved rigorously through a recursive procedure.Comment: Plain TeX source, 26 pages, figures include
Kink-induced symmetry breaking patterns in brane-world SU(3)^3 trinification models
The trinification grand unified theory (GUT) has gauge group SU(3)^3 and a
discrete symmetry permuting the SU(3) factors. In common with other GUTs, the
attractive nature of the fermionic multiplet assignments is obviated by the
complicated multi-parameter Higgs potential apparently needed for
phenomenological reasons, and also by vacuum expectation value (VEV)
hierarchies within a given multiplet. This motivates the rigorous consideration
of Higgs potentials, symmetry breaking patterns and alternative symmetry
breaking mechanisms in models with this gauge group. Specifically, we study the
recently proposed ``clash of symmetries'' brane-world mechanism to see if it
can help with the symmetry breaking conundrum. This requires a detailed
analysis of Higgs potential global minima and kink or domain wall solutions
interpolating between the disconnected global minima created through
spontaneous discrete symmetry breaking. Sufficiently long-lived metastable
kinks can also be considered. We develop what we think is an interesting,
albeit speculative, brane-world scheme whereby the hierarchical symmetry
breaking cascade, trinification to left-right symmetry to the standard model to
colour cross electromagnetism, may be induced without an initial hierarchy in
vacuum expectation values. Another motivation for this paper is simply to
continue the exploration of the rich class of kinks arising in models that are
invariant under both discrete and continuous symmetries.Comment: 12 pages, RevTex, references adde
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