47 research outputs found
Quantum cosmology and the accelerated Universe
The quantized Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) model minimally
coupled to a free massless scalar field is studied and interpreted in the
Bohm-de Broglie framework. We analyze the quantum bohmian trajectories
corresponding to a certain class of gaussian packets, solutions of the
Wheeler-DeWitt equation. We show that these bohmian trajectories undergo an
accelerated expansion in the middle of its evolution due to the presence of
quantum cosmological effects in this period. It is shown that the
luminosity-redshift relation in the quantum cosmological model can be made
close to the corresponding relation coming from the classical model suplemented
by a cosmological constant, for . In this way we have the posibility of
interpreting the present observations of high redshift supernovae as the
consequence of a quantum cosmological effect.Comment: Talk given at X Marcell Grossmann Meeting, Rio de Janeiro, 2003.
Added references and some minor typos correction
Might EPR particles communicate through a wormhole?
We consider the two-particle wave function of an Einstein-Podolsky-Rosen
system, given by a two dimensional relativistic scalar field model. The Bohm-de
Broglie interpretation is applied and the quantum potential is viewed as
modifying the Minkowski geometry. In this way an effective metric, which is
analogous to a black hole metric in some limited region, is obtained in one
case and a particular metric with singularities appears in the other case,
opening the possibility, following Holland, of interpreting the EPR
correlations as being originated by an effective wormhole geometry, through
which the physical signals can propagate.Comment: Corrected version, to appears in EP
New molecular targets in bone metastases
Bone metastases have a major impact on morbidity and on mortality in cancer patients. Despite its clinical relevance, metastasis remains the most poorly elucidated aspect of carcinogenesis. The biological mechanisms leading to bone metastasis establishment have been referred as " vicious circle," a complex network between cancer cells and the bone microenvironment. This review is aimed to underline the new molecular targets in bone metastases management other than bisphosphonates. Different pathways or molecules such as RANK/RANKL/OPG, cathepsin K, endothelin-1, Wnt/DKK1, Src have recently emerged as potential targets and nowadays preclinical and clinical trials are underway. The results from those in the advanced clinical phases are encouraging and underlined the need to design large randomised clinical trials to validate these results in the next future.Targeting the bone by preventing skeletal related events (SREs) and bone metastases has major clinical impact in improving survival in bone metastatic patients and in preventing disease relapse in adjuvant setting. © 2010 Elsevier Ltd
The Consistency of Causal Quantum Geometrodynamics and Quantum Field Theory
We consider quantum geometrodynamics and parametrized quantum field theories
in the framework of the Bohm-de Broglie interpretation. In the first case, and
following the lines of our previous work [1], where a hamiltonian formalism for
the bohmian trajectories was constructed, we show the consistency of the theory
for any quantum potential, completing the scenarios for canonical quantum
cosmology presented there. In the latter case, we prove the consistency of
scalar field theory in Minkowski spacetime for any quantum potential, and we
show, using this alternative hamiltonian method, a concrete example where
Lorentz invariance of individual events is broken.Comment: Final version. See also http://www.cosmologia.cbpf.b