11,070 research outputs found
South African foreign policy and China: converging visions, competing interests, contested identities
South Africa's burgeoning relationship with China exposes the increasing complexities of its post-apartheid international relations. On one hand bilateral relations have deepened since 1998, due to the increasing complementarities with South Africa's foreign policy priorities that emphasise developmental pragmatism and a Southward orientation within the broader African context. On the other hand this relationship emphasises the deeper schisms within South African society itself, where divergent and multi-layered perspectives on South Africa's post-apartheid identity and relationship with China, the country's largest trading partner, remains unresolved. This article maps out the nature of China–South Africa relations through a thematic approach. This allows for nuanced consideration of South Africa's contemporary foreign policy, one that remains compressed between a combination of external and domestic factors
The Minimal GUT with Inflaton and Dark Matter Unification
Giving up the solutions to the fine-tuning problems, we propose the
non-supersymmetric flipped model based on the minimal
particle content principle, which can be constructed from the four-dimensional
models, five-dimensional orbifold models, and local F-theory
models. To achieve gauge coupling unification, we introduce one pair
of vector-like fermions, which form complete
representation. Proton lifetime is around years, neutrino
masses and mixing can be explained via seesaw mechanism, baryon asymmetry can
be generated via leptogenesis, and vacuum stability problem can be solved as
well. In particular, we propose that inflaton and dark matter particle can be
unified to a real scalar field with symmetry, which is not an axion and
does not have the non-minimal coupling to gravity. Such kind of scenarios can
be applied to the generic scalar dark matter models. Also, we find that the
vector-like particle corrections to the masses can be about 6.6%, while
their corrections to the and masses are negligible.Comment: 5 pages, 4 figures;V2: published versio
Accelerating Unruh-DeWitt detectors coupled with a spinor field
The behavior of accelerating Unruh-DeWitt detectors coupled with a spinor
field in (3+1)-dimensional spacetime is investigated. For a single point-like
detector with Gaussian switching function, the transition probability increases
with the acceleration and thus the antiUnruh effect effect cannot occur. Due to
the spinor structure of the Dirac field, UV divergences are encountered in the
calculation of the entanglement between the detectors. After introducing some
UV cutoff , the logarithmic negativity of detectors is shown to behave
nonmonotonically with respect to the acceleration. Besides, the logarithmic
negativity increases with the cutoff and decreases with the distance
between the detectors. The mutual information between the two detectors is also
discussed.Comment: 30 page
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