17,933 research outputs found
Quantization leading to a natural flattening of the axion potential
Starting from the general cosine form for the axion effective potential, we
quantize the axion and show that the result is described by a naturally flat
potential, if interactions with other particles are not considered. This
feature therefore restores the would-be Goldstone-boson nature of the axion,
and we calculate the corresponding vacuum energy density, which does not need
to be too large by orders of magnitude compared to Dark Energy
Comments on branon dressing and the Standard Model
This technical note shows how Electrodynamics and a Yukawa model are dressed
after integrating out perturbative brane fluctuations, and it is found that
first order corrections in the inverse of the brane tension occur for the
fermion and scalar wave functions, the couplings and the masses. Nevertheless,
field redefinitions actually lead to effective actions where only masses are
dressed to this first order. We compare our results with the literature and
find discrepancies at the next order, which, however, might not be measurable
in the valid regime of low-energy brane fluctuations.Comment: 12 page
Emergent relativistic-like Kinematics and Dynamical Mass Generation for a Lifshitz-type Yukawa model
We study the Infra Red (IR) limit of dispersion relations for scalar and
fermion fields in a Lifshitz-type Yukawa model, after dressing by quantum
fluctuations. Relativistic-like dispersion relations emerge dynamically in the
IR regime of the model, after quantum corrections are taken into account. In
this regime, dynamical mass generation also takes place, but in such a way that
the particle excitations remain massive, even if the bare masses vanish. The
group velocities of the corresponding massive particles of course are smaller
than the speed of light, in a way consistent with the IR regime where the
analysis is performed. We also comment on possible extensions of the model
where the fermions are coupled to an Abelian gauge field
Capillarity-Driven Flows at the Continuum Limit
We experimentally investigate the dynamics of capillary-driven flows at the
nanoscale, using an original platform that combines nanoscale pores and
microfluidic features. Our results show a coherent picture across multiple
experiments including imbibition, poroelastic transient flows, and a
drying-based method that we introduce. In particular, we exploit extreme drying
stresses - up to 100 MPa of tension - to drive nanoflows and provide
quantitative tests of continuum theories of fluid mechanics and thermodynamics
(e.g. Kelvin-Laplace equation) across an unprecedented range. We isolate the
breakdown of continuum as a negative slip length of molecular dimension.Comment: 5 pages; 4 figure
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