1,745 research outputs found
The observational constraints on the flat CDM models
Most dark energy models have the CDM as their limit, and if future
observations constrain our universe to be close to CDM Bayesian
arguments about the evidence and the fine-tuning will have to be employed to
discriminate between the models. Assuming a baseline CDM model we
investigate a number of quintessence and phantom dark energy models, and we
study how they would perform when compared to observational data, such as the
expansion rate, the angular distance, and the growth rate measurements, from
the upcoming Dark Energy Spectroscopic Instrument (DESI) survey. We sample
posterior likelihood surfaces of these dark energy models with Monte Carlo
Markov Chains while using central values consistent with the Planck
CDM universe and covariance matrices estimated with Fisher information
matrix techniques. We find that for this setup the Bayes factor provides a
substantial evidence in favor of the CDM model over most of the
alternatives. We also investigated how well the CPL parametrization
approximates various scalar field dark energy models, and identified the
location for each dark energy model in the CPL parameter space.Comment: 11 pages, 5 figures; 4 tables; published in European Journal of
Physics
Research on AR cultural and creative design of Yangming Culture under the background of the integration of culture and technology
The integration of science and technology and culture is a general trend in today’s society, which provides more ways for
cultural exchange and interaction and promotes social development. This study analyzes the application value of AR technology in the
design of cultural and creative products, and reconstructs the process of AR cultural and creative products through the double drill model,
and designs Yangming cultural products based on AR technology. It can be seen from the research that AR technology is gradually integrated
with culture, which can bring new breakthroughs in the transmission, preservation, creation and consumption of culture. This has played a
better role in the dissemination and protection of other traditional Chinese culture and even intangible cultural heritage, further broadening
the design space of cultural and creative products, and making new breakthroughs in the integration of science and technology and culture
UniX-Encoder: A Universal -Channel Speech Encoder for Ad-Hoc Microphone Array Speech Processing
The speech field is evolving to solve more challenging scenarios, such as
multi-channel recordings with multiple simultaneous talkers. Given the many
types of microphone setups out there, we present the UniX-Encoder. It's a
universal encoder designed for multiple tasks, and worked with any microphone
array, in both solo and multi-talker environments. Our research enhances
previous multi-channel speech processing efforts in four key areas: 1)
Adaptability: Contrasting traditional models constrained to certain microphone
array configurations, our encoder is universally compatible. 2) Multi-Task
Capability: Beyond the single-task focus of previous systems, UniX-Encoder acts
as a robust upstream model, adeptly extracting features for diverse tasks
including ASR and speaker recognition. 3) Self-Supervised Training: The encoder
is trained without requiring labeled multi-channel data. 4) End-to-End
Integration: In contrast to models that first beamform then process
single-channels, our encoder offers an end-to-end solution, bypassing explicit
beamforming or separation. To validate its effectiveness, we tested the
UniX-Encoder on a synthetic multi-channel dataset from the LibriSpeech corpus.
Across tasks like speech recognition and speaker diarization, our encoder
consistently outperformed combinations like the WavLM model with the BeamformIt
frontend.Comment: Submitted to ICASSP 202
Positivity from Cosmological Correlators
Effective field theories in flat space and in anti-de Sitter space are
constrained by causality and unitarity, often in the form of positivity bounds.
Similar bounds have been harder to demonstrate in cosmological backgrounds,
where the roles of unitarity and causality are more obscure. Fortunately, the
expansion of the universe ensures that late-time cosmological correlators are
effectively classical and the role of unitarity is played by classical
statistical inequalities. For multi-field inflation, the resulting positivity
constraints have long been known in terms of the Suyama-Yamaguchi inequality.
In this paper, we demonstrate that similar statistical bounds imply nontrivial
constraints for massive fields in the early universe. We show that any real
anomalous dimensions for principal series fields in de Sitter space must be
positive. We also derive a limit on the amplitude of oscillatory signals from
inflation, including those arising in cosmological collider physics. Finally,
we demonstrate that these constraints manifest themselves directly in the
two-point statistics of matter and galaxies that will be measured in upcoming
surveys.Comment: 36 pages; v2: Minor correction
Weak interactions of supersymmetric staus at high energies
Neutrino telescopes may have the potential to detect the quasi-stable staus
predicted by supersymmetric models. Detection depends on stau electromagnetic
energy loss and weak interactions. We present results for the weak interaction
contribution to the energy loss of high energy staus as they pass through rock.
We show that the neutral current weak interaction contribution to the energy
loss increases with energy, but it is much smaller than the photonuclear energy
loss, however, the charged current contribution may become the dominant process
above the energy of GeV, depending on the parameters of the model.
As a consequence, the stau range may be reduced above GeV as
compared to the range neglecting weak interactions. We contrast this with the
tau range which is barely changed with the inclusion of charged current
interactions.Comment: 7 pages, 8 figures, version to be publishe
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