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GPS and the Search for Axions
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作者 a. nicolaidis 《Journal of Modern Physics》 2017年第8期1470-1477,共8页
GPS, an excellent tool for geodesy, may serve also particle physics. In the presence of Earth’s magnetic field, a GPS photon may be transformed into an axion. The proposed experimental setup involves the transmission... GPS, an excellent tool for geodesy, may serve also particle physics. In the presence of Earth’s magnetic field, a GPS photon may be transformed into an axion. The proposed experimental setup involves the transmission of a GPS signal from a satellite to another satellite, both in low orbit around the Earth. To increase the accuracy of the experiment, we evaluate the influence of Earth’s gravitational field on the whole quantum phenomenon. There is a significant advantage in our proposal. While the geomagnetic field B is low, the magnetized length L is very large, resulting into a scale (BL)2 orders of magnitude higher than existing or proposed reaches. The transformation of the GPS photons into axion particles will result in a dimming of the photons and even to a “light shining through the Earth” phenomenon. 展开更多
关键词 AXIONS EARTH Magnetic Field QUANTUM MECHANICS Earth’s GRAVITY Artificial SATELLITES
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Grand Canonical Approach to an Interacting Network
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作者 a. nicolaidis K. Kosmidis V. Kiosses 《Journal of Modern Physics》 2015年第4期472-482,共11页
We consider a network composed of an arbitrary number of directed links. We employ a grand canonical partition function to study the statistical averages of the network in equilibrium. The Hamiltonian is composed of t... We consider a network composed of an arbitrary number of directed links. We employ a grand canonical partition function to study the statistical averages of the network in equilibrium. The Hamiltonian is composed of two parts: a “free” Hamiltonian H0 attributing a constant energy E to each link, and an interacting Hamiltonian Hint involving terms quadratic in the number of links. A Gaussian integration leads to a reformulated Hamiltonian, where now the number of links appears linearly. The reformulated Hamiltonian allows obtaining the exact behavior in limiting cases. At high temperatures the system reproduces the behavior of the free model, while at low temperatures the thermodynamic behavior is obtained by using a renormalized chemical potential, μeff = μ + l, where l is the strength of the interaction. We also resort to a mean field approximation, describing accurately the system over the entire range of all dynamical parameters. A detailed Monte-Carlo simulation verifies our theoretical expectations. We indicate that our model may serve as a prototype model to address a number of different systems. 展开更多
关键词 Complex Networks Statistical MECHANICS MONTE Carlo Simulations GRAND CANONICAL ENSEMBLE
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Dark Neutrinos
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作者 a. nicolaidis 《Journal of Modern Physics》 2012年第12期1979-1982,共4页
Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies... Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies. We study the gravitational clustering of these neutrinos within a model of a massive core and a surrounding spherical neutrino halo. The neutrinos form a degenerate Fermi gas and a loaded polytropic equation is established. We solve the equation and we obtain the neutrino density in a galaxy, the size of the galaxy and the galactic rotational curves. The available data favor a neutrino with a mass around 10 eV. The consequent cosmological implications are examined. 展开更多
关键词 NEUTRINOS NEUTRINO Mass GRAVITATIONAL Clustering DARK MATTER Polytrope EQUATION
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An Axion Interpretation of the ANITA Events
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作者 a. nicolaidis 《Journal of Modern Physics》 2021年第2期59-64,共6页
We suggest that the unusual events observed by the ANITA experiment originate from axion particles traversing the Earth. Under the influence of the geomagnetic field, the axion may oscillate into a photon and vice-ver... We suggest that the unusual events observed by the ANITA experiment originate from axion particles traversing the Earth. Under the influence of the geomagnetic field, the axion may oscillate into a photon and vice-versa. To amplify the axion transition into photon, we consider that the phenomenon takes place at resonance, where the effective photon mass is equal to the axion mass. This requirement fixes the axion mass at 44 eV. An axion at this mass scale reproduces the cold dark matter scenario. If our interpretation prevails, with the help of axions we can establish an axion tomography of the Earth. 展开更多
关键词 AXION Axion-Photon Interaction Earth’s Magnetic Field COSMOLOGY Dark Matter Multimessenger Astronomy
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