338 research outputs found
Dual realizations of dynamical symmetry breaking
We show the infrared equivalence between a recently proposed model containing a six dimensional scalar field with a four-dimensional localized Higgs type potential and the four-dimensional Nambu-Jona-Lasinio (NJL) model. In the dual NJL description, the fermions are localized at the origin of a large two-dimensional compact space. Due to a classical running effect above the compactification scale, the four-fermion coupling of the NJL model increases from the cutoff scale down to the compactification scale, providing the large Fermi coupling needed for the dynamical symmetry breaking. We also present a string theory embedding of our field-theory construction. On more general grounds, our results suggest that 4d models with dynamical symmetry breaking can be given a higher dimensional description in terms of field theories with nontrivial boundary conditions in the internal space
Flowing to four dimensions
We analyze the properties of a model with four-dimensional brane-localized
Higgs type potential of a six dimensional scalar field satisfying the Dirichlet
boundary condition on the boundary of a transverse two-dimensional compact
space. The regularization of the localized couplings generates classical
renormalization group running. A tachyonic mass parameter grows in the
infrared, in analogy with the QCD gauge coupling in four dimensions. We find a
phase transition at a critical value of the bare mass parameter such that the
running mass parameter becomes large in the infrared precisely at the
compactification scale. Below the critical coupling, the theory is in symmetric
phase, whereas above it spontaneous symmetry breaking occurs. Close to the
phase transition point there is a very light mode in the spectrum. The massive
Kaluza-Klein spectrum at the critical coupling becomes independent of the UV
cutoff.Comment: 22 pages, LaTe
Problems with Using Evolutionary Theory in Philosophy
Does science move toward truths? Are present scientific theories (approximately) true? Should we invoke truths to explain the success of science? Do our cognitive faculties track truths? Some philosophers say yes, while others say no, to these questions. Interestingly, both groups use the same scientific theory, viz., evolutionary theory, to defend their positions. I argue that it begs the question for the former group to do so because their positive answers imply that evolutionary theory is warranted, whereas it is self-defeating for the latter group to do so because their negative answers imply that evolutionary theory is unwarranted
Finite temperature behaviour of the ISS-uplifted KKLT model
We study the static phase structure of the ISS-KKLT model for moduli
stabilisation and uplifting to a zero cosmological constant. Since the
supersymmetry breaking sector and the moduli sector are only gravitationally
coupled, we expect negligible quantum effects of the modulus upon the ISS
sector, and the other way around. Under this assumption, we show that the ISS
fields end up in the metastable vacua. The reason is not only that it is
thermally favoured (second order phase transition) compared to the phase
transition towards the supersymmetric vacua, but rather that the metastable
vacua form before the supersymmetric ones. This nice feature is exclusively due
to the presence of the KKLT sector. We also show that supergravity effects are
negligible around the origin of the field space. Finally, we turn to the
modulus sector and show that there is no destabilisation effect coming from the
ISS sector.Comment: 23 pages, 3 figures, mistake corrected, one plot updated, physical
conclusions unchange
Desperate housewives: An analysis of the characterisations of female gamblers portrayed in gambling movies in Hong Kong
This article examines portrayals of female gamblers in recent Hong Kong movies. The authors report that the depiction of female gamblers is very different from that of male gamblers in the movies made in the same period. Whereas the male gamblers are pitching a lonely and desperate battle against the evil opponent, the female gamblers portrayed in the movies are housewives or small-time players who gamble only for their personal gain. A general negative overtone in portrayals of female gamblers was interpreted as a reflection of the traditional view that discourages women from gambling. The shift of gambling themes in the Hong Kong movies has been identified to reflect the most salient concerns among Hong Kong residents. Such changes are attributed to particular social and cultural changes in the community
Novel colours and the content of experience
I propose a counterexample to naturalistic representational theories of phenomenal character. The counterexample is generated by experiences of novel colours reported by Crane and Piantanida. I consider various replies that a representationalist might make, including whether novel colours could be possible colours of objects and whether one can account for novel colours as one would account for binary colours or colour mixtures. I argue that none of these strategies is successful and therefore that one cannot fully explain the nature of the phenomenal character of perceptual experiences using a naturalistic conception of representation
Moduli stabilization and uplifting with dynamically generated F-terms
We use the F-term dynamical supersymmetry breaking models with metastable
vacua in order to uplift the vacuum energy in the KKLT moduli stabilization
scenario. The main advantage compared to earlier proposals is the manifest
supersymmetric treatment and the natural coexistence of a TeV gravitino mass
with a zero cosmological constant. We argue that it is generically difficult to
avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the
metastable vacuum with zero vacuum energy towards them can be very suppressed.
We briefly comment on the properties of the induced soft terms in the
observable sector.Comment: 18 pages, no figures Comments and one reference adde
The Relationship Between Belief and Credence
Sometimes epistemologists theorize about belief, a tripartite attitude on which one can believe, withhold belief, or disbelieve a proposition. In other cases, epistemologists theorize about credence, a fine-grained attitude that represents oneâs subjective probability or confidence level toward a proposition. How do these two attitudes relate to each other? This article explores the relationship between belief and credence in two categories: descriptive and normative. It then explains the broader significance of the belief-credence connection and concludes with general lessons from the debate thus far
Evidence for early life in Earthâs oldest hydrothermal vent precipitates
Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetiteâhaematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago
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