65,251 research outputs found
Quanta transfer in space is conserved
The paper is replaced by a new version (12-2019): DOI: 10.5281/zenodo.3572846
Physical phenomena emerge from the quantum fields everywhere in space. However, not only the phenomena emerge from the quantum fields, the law of the conservation of energy must have its origin from the same spatial structure. This paper describes the relations between the main law of physics and the mathematical structure of the “aggregated” quantum fields
Noncollinear magnetic order in quasicrystals
Based on Monte-Carlo simulations, the stable magnetization configurations of
an antiferromagnet on a quasiperiodic tiling are derived theoretically. The
exchange coupling is assumed to decrease exponentially with the distance
between magnetic moments. It is demonstrated that the superposition of
geometric frustration with the quasiperiodic ordering leads to a
three-dimensional noncollinear antiferromagnetic spin structure. The structure
can be divided into several ordered interpenetrating magnetic supertilings of
different energy and characteristic wave vector. The number and the symmetry of
subtilings depend on the quasiperiodic ordering of atoms.Comment: RevTeX, 4 pages, 5 low-resolution color figures (due to size
restrictions); to appear in Physical Review Letter
Why Study History? On Its Epistemic Benefits and Its Relation to the Sciences
I try to return the focus of the philosophy of history to the nature of understanding, with a particular emphasis on Louis Mink’s project of exploring how historical understanding compares to the understanding we find in the natural sciences. On the whole, I come to a conclusion that Mink almost certainly would not have liked: that the understanding offered by history has a very similar epistemic profile to the understanding offered by the sciences, a similarity that stems from the fact that both are concerned with grasping how the objects of their study are structured, or how the various elements of the things they study depend upon and relate to one another. At the same time, however, I claim that historical inquiry naturally puts us in a position to acquire further epistemic goods, including the old-fashioned epistemic good of wisdom, which is plausibly constituted by knowledge of how to live well. This is something the natural sciences cannot offer, and it is part of the reason why history is such an important form of inquiry
The N=1 effective action of F-theory compactifications
The four-dimensional N=1 effective action of F-theory compactified on a
Calabi-Yau fourfold is studied by lifting a three-dimensional M-theory
compactification. The lift is performed by using T-duality realized via a
Legendre transform on the level of the effective action, and the application of
vector-scalar duality in three dimensions. The leading order Kahler potential
and gauge-kinetic coupling functions are determined. In these compactifications
two sources of gauge theories are present. Space-time filling non-Abelian
seven-branes arise at the singularities of the elliptic fibration of the
fourfold. Their couplings are included by resolving the singular fourfold.
Generically a U(1)^r gauge theory arises from the R-R bulk sector if the base
of the elliptically fibered Calabi-Yau fourfold supports 2r harmonic
three-forms. The gauge coupling functions depend holomorphically on the complex
structure moduli of the fourfold, comprising closed and open string degrees of
freedom. The four-dimensional electro-magnetic duality is studied in the
three-dimensional effective theory obtained after M-theory compactification. A
discussion of matter couplings transforming in the adjoint of the seven-brane
gauge group is included.Comment: 59 pages, v2: references added, typos correcte
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