94 research outputs found
Clockworked VEVs and Neutrino Mass
In this paper we present an augmented version of the Abelian scalar clockwork
model to generate geometrically suppressed vacuum expectation values (vev) of
the pseudo Nambu-Goldstone bosons, that we call the clockworked vevs. We
briefly comment on generalization of the setup and possible 5D UV realizations.
We demonstrate how tiny neutrino mass can be generated by clockworking a weak
scale vev.Comment: 13 pages, 2 captioned figures, 1 table, further clarifications added
in text, references updated, matches version published in JHE
Heavily separable functors of the second kind and applications
We introduce heavily separable functors of the second kind and study them in
three different situations. The first of these is with restrictions and
extensions of scalars for modules over small preadditive categories. The second
is with free functors taking values in Eilenberg-Moore categories associated to
a monad or a comonad. Finally, we consider entwined modules and give if and
only if conditions for heavy separability of the second kind for functors
forgetting either the comodule action or the module action
Hilbert spaces over -tensor categories, Fredholm modules and cyclic cohomology
We construct Fredholm modules over an algebra taking values in generalized
Hilbert spaces over a rigid -tensor category. Using methods of Connes, we
obtain Chern characters taking values in cyclic cohomology. These Chern
characters are well behaved with respect to the periodicity operator, and
depend only on the homotopy class of the Fredholm module
The Elusive member of the Ti-Al-C MAX family- Ti4AlC3
We report here perhaps the first successful synthesis and structural
characterization of the n=3 family member of Tin+1AlCn, i. e. Ti4AlC3. X-ray
Powder diffraction (XRD) data shows characteristic reflections of from
corresponding to reflections from the (002), (004), (006), (008), (100), (102),
(104), (0010), (105), (106), (0012), (1011) and (1012) planes at 2{\theta}
=7.640, 15.170, 22.760, 30.50, 350, 37.40 38.30, 39.20, 41.30, 46.220, 55.240,
58.620 and 60.780 (double structure) respectively. Rietveld refinement of the
XRD data reveals a phase purity of about 79 % for alpha-Ti4AlC3, 15 % for
beta-Ti4AlC3 and the rest mostly that of cubic TiC (6 %). The primary crystal
symmetry of the two dominant phases is the hexagonal P63/mmc. The precursors
chosen were TiH2, Al metal powder and Carbon powder in a molar ratio of
3:1.2:2, which build the case for an Al-deficient condition. We adopted the
pressureless sintering technique at 13500 C with a dwelling time of 4 hours
under ultra-high vacuum of 10-7 mbar. The co-existence of trace amount of
Ti2AlC at 1350 deg C is proven by the small structure at 2{\theta}=13.130. No
trace of oxides like Al2O3 or TiO2 was found in the end product. The line
profile width of XRD data indicates average grain size of the order of micro
meter. The Scanning Electron Microscopy images show highly lamellar stacked
growth of almost a pure MAX (alpha or beta) phase and grain size of micron
order, agreeing well with the XRD data
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