Leggett–Garg inequality (LGI) is a time analogue of Bell’s inequality that concerns measurements performed on a system at different times. Violation to LGI indicates quantum coherence. We present a ...Leggett–Garg-type inequality compatible with more general neutrino oscillation frameworks, allowing the effects of decoherence to be taken into consideration. The inequality is applied to test coherence for data from Daya Bay, MINOS, and KamLAND experiments, and their results are compared to theoretical predictions to investigate decoherence. Both Daya Bay and MINOS data exhibit clear violations of over
10
σ
, and of over 90
%
of theoretical predictions, while the KamLAND data exhibit violation of
1.9
σ
, being of 58
%
of the theoretical prediction. The present work is the first to have considered the energy uncertainties in neutrino coherence tests.
The Large High Altitude Air Shower Observatory (LHAASO) recently reported the detection of gamma-ray emissions with energies up to 1.1PeV from the Crab Nebula. Using the absence of vacuum Cherenkov ...effect by inverse-Compton electrons, we improve previous bounds to linear-order Lorentz invariance violation (LV) in the dispersion relations of electrons by 104 times. We show that the LV effect on electrons is severely constrained, compatible with certain type of LV as expected by some models of quantum gravity (QG), such as the string/D-brane inspired space-time foam. We argue that such models are supported by the Crab Nebula constraints from the LHAASO observations, as well as various LV phenomenologies for photons to date.
A recent proposal to associate 60 TeV to 2 PeV IceCube neutrino events with gamma-ray bursts (GRBs) indicates the Lorentz violation of cosmic neutrinos and leads further to the CPT symmetry violation ...between neutrinos and antineutrinos. Here we find that another 12 northern hemisphere track events possibly correlated with GRBs from three-year IceCube data satisfy the same regularity at a lower energy scale around 1 TeV. The combined fitting indicates a Lorentz violation scale ELV=(6.4±1.5)×1017 GeV and an intrinsic time difference Δtin=(−2.8±0.7)×102 s, from which we find an earlier emission of neutrinos than photons at the GRB source. We also suggest analyzing neutrino events detected a few minutes before the GRB trigger time to test the CPT violation of ultrahigh-energy neutrinos.
A
bstract
Previous studies on high-energy gamma-ray burst neutrinos from IceCube suggest a neutrino speed variation at the Lorentz violation (LV) scale of ~6
.
4 × 10
17
GeV, with opposite velocity ...variances between neutrinos and antineutrinos. Within a spacetime foam model, inspired by string theory, we develop an approach to describe the suggested neutrino/antineutrino propagation properties with both Lorentz invariance and CPT symmetry breaking. A threshold analysis on the bremsstrahlung of electron-positron pair (
ν
→
νee
+
) for the superluminal (anti)neutrino is performed. We find that, due to the energy violation caused by the quantum foam, such reaction may be restricted to occur at sufficient high energies and could even be kinematically forbidden. Constraints on neutrino LV from vacuum
ee
+
pair emission are naturally avoided. Future experiments are appealed to test further the CPT violation of cosmic neutrinos and/or neutrino superluminality.
Recently a series of analyses on the flight time of cosmic photons and neutrinos suggests that the speed of light in vacuo takes the energy-dependent form v(E)≃1−E/ELIVγ with ELIVγ≈3.6×1017GeV, and ...meanwhile the speed of neutrinos is proposed to be v(E)≃1±E/ELIVν with ELIVν≈6.5×1017GeV and ± representing the helicity dependence. This novel picture immediately urges us to provide a satisfactory theoretical explanation. Among all the attempts to predict the speed variations from quantum gravity, we find that loop quantum gravity can serve as a good candidate for explaining the aforementioned picture consistently.
Wheat head detection can estimate various wheat traits, such as density, health, and the presence of wheat head. However, traditional detection methods have a huge array of problems, including low ...efficiency, strong subjectivity, and poor accuracy. In this paper, a method of wheat-head detection based on a deep neural network is proposed to enhance the speed and accuracy of detection. The YOLOv4 is taken as the basic network. The backbone part in the basic network is enhanced by adding dual spatial pyramid pooling (SPP) networks to improve the ability of feature learning and increase the receptive field of the convolutional network. Multilevel features are obtained by a multipath neck part using a top-down to bottom-up strategy. Finally, YOLOv3's head structures are used to predict the boxes of wheat heads. For training images, some data augmentation technologies are used. The experimental results demonstrate that the proposed method has a significant advantage in accuracy and speed. The mean average precision of our method is 94.5%, and the detection speed is 71 FPS that can achieve the effect of real-time detection.
•MoS2 nanosheets with different morphologies on Mo foil were synthesized.•The effects of the concentration of thiourea on the morphology and FE properties of MoS2 were investigated.•Low turn-on field ...of ∼1.90 V/μm with a high β of 1979 was achieved.
Free-standing molybdenum disulfide (MoS2) nanosheets with different morphologies on molybdenum (Mo) foil were synthesized through hydrothermal method using thiourea as the sulphur source and Mo foil as the Mo source. The effect of the concentration of thiourea in the reaction solution on the morphology and field emission (FE) properties of MoS2 nanosheets were investigated. The vertically aligned MoS2 nanosheets exhibit a low turn-on (∼1.90 V/μm) and threshold electric field (∼2.51 V/μm), along with good emission stability. The results are attributed to the high geometrical field enhancement factor (∼1979) and the sturdy structure of the MoS2 grown on highly conductive Mo substrate.
•We analyse the data of the energetic photons from the gamma-ray bursts (GRBs).•We find events to support the energy dependence in the light speed.•We provide scenarios to understand the Fermi-LAT ...Pass 8 data of bright GRBs.•The predictions from such scenarios are testable by future detected GRBs.
The constancy of light speed is a basic assumption in Einstein’s special relativity, and consequently the Lorentz invariance is a fundamental symmetry of space–time in modern physics. However, it is speculated that the speed of light becomes energy-dependent due to the Lorentz invariance violation (LV) in various new physics theories. We analyse the data of the energetic photons from the gamma-ray bursts (GRBs) by the Fermi Gamma-Ray Space Telescope, and find more events to support the energy dependence in the light speed with both linear and quadratic form corrections. We provide two scenarios to understand all the new-released Pass 8 data of bright GRBs by the Fermi-LAT Collaboration, with predictions from such scenarios being testable by future detected GRBs.
PDF
