37 research outputs found
A condensed matter interpretation of SM fermions and gauge fields
We present the bundle Aff(3) x C x /(R^3), with a geometric Dirac equation on
it, as a three-dimensional geometric interpretation of the SM fermions. Each C
x /(R^3) describes an electroweak doublet. The Dirac equation has a
doubler-free staggered spatial discretization on the lattice space Aff(3) x C
(Z^3). This space allows a simple physical interpretation as a phase space of a
lattice of cells in R^3. We find the SM SU(3)_c x SU(2)_L x U(1)_Y action on
Aff(3) x C x /(R^3) to be a maximal anomaly-free special gauge action
preserving E(3) symmetry and symplectic structure, which can be constructed
using two simple types of gauge-like lattice fields: Wilson gauge fields and
correction terms for lattice deformations. The lattice fermion fields we
propose to quantize as low energy states of a canonical quantum theory with
Z_2-degenerated vacuum state. We construct anticommuting fermion operators for
the resulting Z_2-valued (spin) field theory. A metric theory of gravity
compatible with this model is presented too.Comment: Minimal modifications in comparison with the published versio
On the Decomposition of Clifford Algebras of Arbitrary Bilinear Form
Clifford algebras are naturally associated with quadratic forms. These
algebras are Z_2-graded by construction. However, only a Z_n-gradation induced
by a choice of a basis, or even better, by a Chevalley vector space isomorphism
Cl(V) \bigwedge V and an ordering, guarantees a multi-vector decomposition
into scalars, vectors, tensors, and so on, mandatory in physics. We show that
the Chevalley isomorphism theorem cannot be generalized to algebras if the
Z_n-grading or other structures are added, e.g., a linear form. We work with
pairs consisting of a Clifford algebra and a linear form or a Z_n-grading which
we now call 'Clifford algebras of multi-vectors' or 'quantum Clifford
algebras'. It turns out, that in this sense, all multi-vector Clifford algebras
of the same quadratic but different bilinear forms are non-isomorphic. The
usefulness of such algebras in quantum field theory and superconductivity was
shown elsewhere. Allowing for arbitrary bilinear forms however spoils their
diagonalizability which has a considerable effect on the tensor decomposition
of the Clifford algebras governed by the periodicity theorems, including the
Atiyah-Bott-Shapiro mod 8 periodicity. We consider real algebras Cl_{p,q} which
can be decomposed in the symmetric case into a tensor product Cl_{p-1,q-1}
\otimes Cl_{1,1}. The general case used in quantum field theory lacks this
feature. Theories with non-symmetric bilinear forms are however needed in the
analysis of multi-particle states in interacting theories. A connection to
q-deformed structures through nontrivial vacuum states in quantum theories is
outlined.Comment: 25 pages, 1 figure, LaTeX, {Paper presented at the 5th International
Conference on Clifford Algebras and their Applications in Mathematical
Physics, Ixtapa, Mexico, June 27 - July 4, 199
Dirty and 40 days in the wilderness: Eliciting childbirth and postnatal cultural practices and beliefs in Nepal.
Background: Pregnancy and childbirth are socio-cultural events that carry varying meanings across different societies and cultures. These are often translated into social expectations of what a particular society expects women to do (or not to do) during pregnancy, birth and/or the postnatal period. This paper reports a study exploring beliefs around childbirth in Nepal, a low-income country with a largely Hindu population. The paper then sets these findings in the context of the wider global literature around issues such as periods where women are viewed as polluted (or dirty even) after childbirth. Methods: A qualitative study comprising five in-depth face-to-face interviews and 14 focus group discussions with mainly women, but also men and health service providers. The qualitative findings in Nepal were compared and contrasted with the literature on practices and cultural beliefs related to the pregnancy and childbirth period across the globe and at different times in history. Results: The themes that emerged from the analysis included: (a) cord cutting & placenta rituals; (b) rest & seclusion; (c) purification, naming & weaning ceremonies and (d) nutrition and breastfeeding. Physiological changes in mother and baby may underpin the various beliefs, ritual and practices in the postnatal period. These practices often mean women do not access postnatal health services. Conclusions: The cultural practices, taboos and beliefs during pregnancy and around childbirth found in Nepal largely resonate with those reported across the globe. This paper stresses that local people’s beliefs and practices offer both opportunities and barriers to health service providers. Maternity care providers need to be aware of local values, beliefs and traditions to anticipate and meet the needs of women, gain their trust and work with them
Annales de la Fondation Louis de Broglie
RÉSUMÉ. Les déchargesélectriques effectuées avec des fils de titane dans de l'eau créent des monopôles magnétiques. Ceux-ci sont visibles directement ou indirectement par leur action sur des plaques photographiques ou dans les poudres issues des tirs. Ce sont ces effets directs et indirects qui sont passés en revue ici ABSTRACT: Electrical explosions of a titanium wire in water create magnetic monopoles. They are seen directly or indirectly by their effects on photographic plates or by properties of powders resulting from the electrical discharge. These direct and indirect effects are reviewed. We report here results obtained from the trials done at Ecole Centrale de Nantes, comparing with the result of experiments conducted by L. Urutskoev. To be close to his work, our electrical discharges were performed on titanium wires in water. The discharge causes the creation of a plasma and a shock wave, and hence the device is installed within a metal enclosure (Stainless steel /Aluminum) to avoid radiation effects. The device is protected from the discharge by having a polyurethane insulation. This insulation has been covered with a 2 mm layer of Teflon for security measures. The only metal present within this metal enclosure is the Ti40, a high quality titanium. This setup was explained in a previous report of our work [1]. The results must be regarded as partial, provisional. They may be increased if the necessary improvements can be made. However, these results seem sufficiently important from a scientific point of view for us to present them. Direct observation of magnetic monopoles and their traces on film are reported in [2], in this article, we describe our other results
La coagulation présure du lait écrémé et l'égouttage : effet du pH et de la concentration en caséine, de la force ionique et du traitement thermique
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