7,709 research outputs found
Weak Forces and Neutrino Oscillations under the standards of Hybrid Gravity with Torsion
We present a unifying approach where weak forces and neutrino oscillations
are interpreted under the same standards of torsional hybrid gravity. This
gravitational theory mixes metric and metric-affine formalism in presence of
torsion and allows to derive an effective scalar field which gives rise to a
running coupling for Dirac matter fields. In this picture, two phenomena
occurring at different energy scales can be encompassed under the dynamics of
such a single scalar field, which represents the further torsional and
curvature degrees of freedom.Comment: 13 page
All Optical Switch of Vacuum Rabi Oscillations: The Ultrafast Quantum Eraser
We study the all-optical time-control of the strong coupling between a single
cascade three-level quantum emitter and a microcavity. We find that only
specific arrival-times of the control pulses succeed in switching-off the Rabi
oscillations. Depending on the arrival times of control pulses, a variety of
exotic non-adiabatic cavity quantum electrodynamics effects can be observed. We
show that only control pulses with specific arrival times are able to suddenly
switch-off and -on first-order coherence of cavity photons, without affecting
their strong coupling population dynamics. Such behavior may be understood as a
manifestation of quantum complementarity
A Solitonic Approach to Holographic Nuclear Physics
We discuss nuclear physics in the Sakai-Sugimoto model in the limit of large
number of colors and large 't Hooft coupling . In this limit the
individual baryons are described by classical solitons whose size is much
smaller than the typical distance at which they settle in a nuclear bound
state. We can thus use the linear approximation outside the instanton cores to
compute the interaction potential. We find the classical geometry of nuclear
bound states for baryon number up to eight. One of the interesting features
that we find is that holographic nuclear physics provides a natural description
for lightly bound states when is large. For the case of two nuclei,
we also find the topology and metric of the manifold of zero modes and,
quantizing it, we find that the ground state can be identified with the
deuteron state. We discuss the relations with other methods in the literature
used to study Skyrmions and holographic nuclear physics. We discuss
and corrections and the challenges to overcome to reach the
phenomenological values to fit with real QCD.Comment: 47 pages, 7 figures. v2: typos correcte
Il Senato che (non) è stato, che è e che sarà . Un deciso miglioramento
Sono delineate le funzioni del Senato come modificato dalla riforma costituzionale in una prospettiva storica e comparatistica.Are outlined the functions of the Senate as amended by the constitutional reform in a historical and comparative perspective
On the well formulation of the Initial Value Problem of metric--affine -gravity
We study the well formulation of the initial value problem of f(R)-gravity in
the metric-affine formalism. The problem is discussed in vacuo and in presence
of perfect-fluid matter, Klein-Gordon and Yang-Mills fields. Adopting Gaussian
normal coordinates, it can be shown that the problem is always well-formulated.
Our results refute some criticisms to the viability of f(R)-gravity recently
appeared in literature.Comment: 11 page
Photodetection probability in quantum systems with arbitrarily strong light-matter interaction
Cavity-QED systems have recently reached a regime where the light-matter
interaction strength amounts to a non-negligible fraction of the resonance
frequencies of the bare subsystems. In this regime, it is known that the usual
normal-order correlation functions for the cavity-photon operators fail to
describe both the rate and the statistics of emitted photons. Following
Glauber's original approach, we derive a simple and general quantum theory of
photodetection, valid for arbitrary light-matter interaction strengths. Our
derivation uses Fermi's golden rule, together with an expansion of system
operators in the eigenbasis of the interacting light-matter system, to arrive
at the correct photodetection probabilities. We consider both narrow- and
wide-band photodetectors. Our description is also valid for point-like
detectors placed inside the optical cavity. As an application, we propose a
gedanken experiment confirming the virtual nature of the bare excitations that
enrich the ground state of the quantum Rabi model.Comment: 9 pages, 1 figur
Paleoenvironmental implications through the study of an Eemian paleosol in northwestern Sardinia (Italy)
The aim of this work is to define the paleoenvironmental changes related to a soil belonging to the studied succession, by means of an in-depth micromorphological study. In particular, the presence of this paleosol is associated to the fast climatic fluctuations that took place between MIS5e and MIS5c
The Cauchy problem in hybrid metric-Palatini f(X)-gravity
The well-formulation and the well-posedness of the Cauchy problem is
discussed for {\it hybrid metric-Palatini gravity}, a recently proposed
modified gravitational theory consisting of adding to the Einstein-Hilbert
Lagrangian an term constructed {\it \`{a} la} Palatini. The theory can
be recast as a scalar-tensor one predicting the existence of a light long-range
scalar field that evades the local Solar System tests and is able to modify
galactic and cosmological dynamics, leading to the late-time cosmic
acceleration. In this work, adopting generalized harmonic coordinates, we show
that the initial value problem can always be {\it well-formulated} and,
furthermore, can be {\it well-posed} depending on the adopted matter sources.Comment: 7 page
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