127,493 research outputs found
Fiber averaged dynamics associated with the Lorentz force equation
It is shown that the Lorentz force equation is equivalent to the
auto-parallel condition \,^L\nabla_{\dot{{x}}}\dot{{x}}=0 of a linear
connection defined on a convenient pull-back vector bundle. By using
a geometric averaging method, an associated {\it averaged Lorentz connection}
\langle\,^L\nabla\rangle and the corresponding auto-parallel equation are
obtained. After this, it is shown that in the ultra-relativistic limit and for
narrow one-particle probability distribution functions, the auto-parallel
curves of \langle\,^L\nabla\rangle remain {\it nearby} close to the
auto-parallel curves of . Applications of this result in beam
dynamics and plasma physics are briefly described.Comment: This version, except for very few typographical corrections and
several changes in the bibliography, was published in Journal of Geometry and
Physic
Filtered-graded transfer of noncommutative Gr\"obner bases
As the case of free -algebras and algebras, given a bijective
skew extension , we will show that it is possible transfer Gr\"obner
bases between and its associated graded ring.Comment: arXiv admin note: text overlap with arXiv:1309.0483 by other author
Effective upliftings in Large volume compactifications
After reviewing several mechanisms proposed to get a dS/Minkowski vacuum in
moduli stabilization scenarios of type-IIB superstring orientifold
compactifications we propose a criterium for characterizing those that may
effectively lead to a positive small cosmological constant.
We suggest that the variation in the expectation value of a good uplifting
term, due to the shift in the minimum of the potential after uplifting, is much
smaller than the original cosmological constant. This is studied with some
detail in Large volume scenarios where the dependency on the volume direction
is rather generic and easy to spot. Here we find that an uplifting term in the
potential, with generic form , should be
restricted to the one satisfying .
Such a bound might explain why in models previously studied no uplifting has
been achieved, and gives motivations to study a novel proposal of dilaton
dependent uplifting mechanism for which no numerical studies has been performed
before. We find that in this case it is actually possible to get a dS vacuum,
but still leave open the question of a more precise discrimination feature the
good uplifting mechanisms should satisfy.Comment: 8 pgs, 1 figure. To be submitted for publication in Nuclear physics B
Proceedings Supplements-Special Issue X SILAFAE; v2 typos fixed, references
adde
Foundations for a theory of emergent quantum mechanics and emergent classical gravity
Quantum systems are viewed as emergent systems from the fundamental degrees
of freedom. The laws and rules of quantum mechanics are understood as an
effective description, valid for the emergent systems and specially useful to
handle probabilistic predictions of observables. After introducing the
geometric theory of Hamilton-Randers spaces and reformulating it using Hilbert
space theory, a Hilbert space structure is constructed from the Hilbert space
formulation of the underlying Hamilton-Randers model and associated with the
space of wave functions of quantum mechanical systems. We can prove the
emergence of the Born rule from ergodic considerations. A geometric mechanism
for a natural spontaneous collapse of the quantum states based on the
concentration of measure phenomena as it appears in metric geometry is
discussed.We show the existence of stable vacua states for the quantized matter
Hamiltonian. Another consequence of the concentration of measure is the
emergence of a weak equivalence principle for one of the dynamics of the
fundamental degrees of freedom. We suggest that the reduction of the quantum
state is driven by a gravitational type interaction.
Such interaction appears only in the dynamical domain when localization of
quantum observables happens, it must be a classical interaction. We discuss the
double slit experiment in the context of the framework proposed, the
interference phenomena associated with a quantum system in an external
gravitational potential, a mechanism explaining non-quantum locality and also
provide an argument in favour of an emergent interpretation of every
macroscopic time parameter. Entanglement is partially described in the context
of Hamilton-Randers theory and how naturally Bell's inequalities should be
violated.Comment: Extensive changes in chapter 1 and chapter 2; minor changes in other
chapters; several refereces added and others update; 192 pages including
index of contents and reference
Jacobi equations and particle accelerator beam dynamics
A geometric formulation of the linear beam dynamics in accelerator physics is
presented. In particular, it is proved that the linear transverse and
longitudinal dynamics can be interpret geometrically as an approximation to the
Jacobi equation of an affine averaged Lorentz connection. We introduce a
specific notion reference trajectory as integral curves of the main velocity
vector field. A perturbation caused by the statistical nature of the bunch of
particles is considered.Comment: 16 page
- …