50,992 research outputs found
On Structure and Organization: An Organizing Principle
We discuss the nature of structure and organization, and the process of
making new Things. Hyperstructures are introduced as binding and organizing
principles, and we show how they can transfer from one situation to another. A
guiding example is the hyperstructure of higher order Brunnian rings and
similarly structured many-body systems.Comment: Minor revision of section
Computational Design of Axion Insulators Based on 5d Spinels Compounds
Based on density functional calculation with LDA+U method, we propose that
hypothetical Osmium compounds such as CaOs2O4 and SrOs2O4 can be stabilized in
the geometrically frustrated spinel crystal structure. They also show some
exotic electronic and magnetic properties in a reasonable range of on-site
Coulomb correlation U such as ferromagnetism and orbital magnetoelectric effect
characteristic to Axion electrodynamics. Other electronic phases including 3D
Dirac metal and Mott insulator exist and would make perspective 5d spinels
ideal for applications.Comment: 5 pages, 3 figure
Model as a Topological Description of String Theory
We study the model coupled to topological gravity as a candidate
to describing string theory at the self-dual radius. We define the model
by analytical continuation of topological recursion relations to .
We show that at genus zero the recursion relations yield the
Ward identities for tachyon correlators on the sphere. A scheme
for computing correlation functions of gravitational descendants is
proposed and applied for the computation of several correlators. It is
suggested that the latter correspond to correlators of discrete states of the
string. In a similar manner to the models, we show that there exist
topological recursion relations for the correlators in the theory that
consist of only one and two splittings of the Riemann surface. Using a
postulated regularized contact, we prove that the genus one recursion
relations for tachyon correlators coincide with the Ward
identities on the torus. We argue that the structure of these recursion
relations coincides with that of the Ward identities for any
genus.Comment: 39 pages,latex,taup-2170 -9
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