322 research outputs found

### Possible scenario for MaVaN's as the only neutrino flavor conversion mechanism in the Sun

Mass Varying neutrino mechanisms were proposed to link the neutrino mass
scale with dark energy, addressing the coincidence problem. In some scenarios
this mass can present a dependence on the baryonic density felt by neutrinos,
creating an effective neutrino mass that depends both on the neutrino and
baryonic densities. In this article we investigate the possibility that a
neutrino effective mass is the only flavour conversion mechanism acting in
neutrino oscillation experiments. We present a parameterization on the
environmental effects on neutrino mass that produces the right flavour
conversion probabilities for solar and terrestrial neutrinos experiments.Comment: 12 pages, 4 figure

### Quantum Dissipation in a Neutrino System Propagating in Vacuum and in Matter

Considering the neutrino state like an open quantum system, we analyze its
propagation in vacuum or in matter. After defining what can be called
decoherence and relaxation effects, we show that in general the probabilities
in vacuum and in constant matter can be written in a similar way, which is not
an obvious result in this approach. From this result, we analyze the situation
where neutrinos evolution satisfies the adiabatic limit and use this formalim
to study solar neutrinos. We show that the decoherence effect may not be
bounded by the solar neutrino data and review some results in the literature.
We discuss the current results where solar neutrinos were used to put bounds on
decoherence effects through a model-dependent approach. We conclude explaining
how and why this models are not general and we reinterpret these constraints.Comment: new version: title was changend and was added a table. To appear at
Nucl. Physic.

### Relational queries with a tensor processing unit

Tensor Processing Units are specialized hardware devices built to train and apply Machine Learning models at high speed through high-bandwidth memory and massive instruction parallelism. In this short paper, we investigate how relational operations can be translated to those devices. We present mapping of relational operators to TPU-supported TensorFlow operations and experimental results comparing with GPU and CPU implementations. Results show that while raw speeds are enticing, TPUs are unlikely to improve relational query processing for now due to a variety of issues

### REPRESENTAÃ‡Ã•ES SOBRE A MORTE EM FORTALEZA-CE (1920 â€“ 1940)

Com a constataÃ§Ã£o da relevÃ¢ncia dos estudos histÃ³ricos acerca dos temas vinculados Ã morte, o presente trabalho, cujo objetivo Ã© investigar as prÃ¡ticas e representaÃ§Ãµes fÃºnebres na cidade de Fortaleza â€“ CE, parte da percepÃ§Ã£o de que as mudanÃ§as ocorridas na cidade e no seu cotidiano entre os anos de 1920 e 1940 acarretam novas formas de convivÃªncia e ritualizaÃ§Ã£o dos atos fÃºnebres e suas representaÃ§Ãµes. Para esse estudo, utilizou-se as obras de dois memorialistas que escreveram sobre os ditos anos: JoÃ£o Nogueira e Eduardo Campos. Verifica-se que a modernidade acaba por transformar as prÃ¡ticas fÃºnebres e cada um desses memorialistas observa essas modificaÃ§Ãµes atravÃ©s de uma Ã³ptica prÃ³pria

### On the Effects of Quantum Decoherence in a Future Supernova Neutrino Detection

Quantum decoherence effects in neutrinos, described by the open quantum
systems formalism, serve as a gateway to explore potential new physics,
including quantum gravity. Previous research extensively investigated these
effects across various neutrino sources, imposing stringent constraints on the
spontaneous loss of coherence. In this study, we demonstrate that even within
the Supernovae environment, where neutrinos are released as incoherent states,
quantum decoherence could influence the flavor equipartition of $3\nu$ mixing.
Additionally, we examine the potential energy dependence of quantum decoherence
parameters ($\Gamma = \Gamma_0 (E/E_0)^n$) with different power laws ($n = 0,
2, 5/2$). Our findings indicate that future-generation detectors (DUNE,
Hyper-K, and JUNO) can significantly constrain quantum decoherence effects
under different scenarios. For a Supernova located 10 kpc away from Earth, DUNE
could potentially establish $3\sigma$ bounds of $\Gamma \leq 6.2 \times
10^{-14}$ eV in the normal mass hierarchy (NH) scenario, while Hyper-K could
impose a $2\sigma$ limit of $\Gamma \leq 3.6 \times 10^{-14}$ eV for the
inverted mass hierarchy (IH) scenario with $n=0$ - assuming no energy exchange
between the neutrino subsystem and non-standard environment ($[H,V_p] = 0$).
These limits become even more restrictive for a closer Supernova. When we relax
the assumption of energy exchange ($[H,V_p] \neq 0$), for a 10 kpc SN, DUNE can
establish a $3\sigma$ limit of $\Gamma_8 \leq 4.2 \times 10^{-28}$ eV for NH,
while Hyper-K could constrain $\Gamma_8 \leq 1.3 \times 10^{-27}$ eV for IH
($n=0$) with $2\sigma$, representing the most stringent bounds reported to
date. Furthermore, we examine the impact of neutrino loss during propagation
for future Supernova detection

### SN1987A neutrino burst: limits on flavor conversion

In this paper, we revisit the SN1987A neutrino data to see its constraints on
flavor conversion. We are motivated by the fact that most works that analyze
this data consider a specific conversion mechanism, such as the MSW
(Mikheyev-Smirnov-Wolfenstein) effect, although flavor conversion is still an
open question in supernovae due to the presence of neutrino-neutrino
interactions. In our analysis, instead of considering a specific conversion
mechanism, we let the electron antineutrino survival probability
$P_{\overline{e}\overline{e}}$ be a free parameter. We fit the data from
Kamiokande-II, Baksan, and IMB detected spectrum with two classes of models:
time-integrated and time-dependent. For the time-integrated model, it is not
possible to put limits above $1\sigma$ (68% confidence level) on the survival
probability. The same happens for the time-dependent model when cooling is the
only mechanism of antineutrino emission. However, for models considering an
accretion phase, $P_{\overline{e}\overline{e}}\sim0$ is strongly rejected,
showing a preference for the existence of an accretion component in the
detected antineutrino flux, and a preference for normal mass ordering when only
the MSW is present.Comment: 13 pages,10 figures. Version Accepted for publication. Some updates
were made in the analysis with no significant deviations from previous
result

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