Search results for " relativity"
showing 10 items of 1158 documents
Mass and Gravity
2014
The book starts with a survey on the development of the concept ‘mass’ and of theories of gravity, beginning with Greek’s ideas on mass, Galileo’s experiments, Newton’s laws and their extension by Einstein’s theory of relativity. Data from measurements of the gravitational force on Sun, planets and the Moon are presented. Kepler’s laws on moving masses in the gravitational field are discussed as well as new discoveries on the expansion of the universe. Fundamental interactions of particles and particle/wave duality are described. The Theory of Everything is mentioned. The definition of the international unit of mass is reported as well as alternatives like watt or voltage balance, counting …
Thermodynamic perfect fluid spheres admitting an orthogonal flat synchronization
2022
We analyze the interpretation of the spherically symmetric perfect fluid solutions that admit a flat synchronization orthogonal to the fluid flow as a thermodynamic perfect fluid in local thermal equilibrium. The ideal gas sonic condition is examined for this family of metrics, and the macroscopic conditions for physical reality are accurately tested for some specific solutions.
Relativistic holonomic fluids
1989
The notion of holonomic fluid in relativity is reconsidered. An intrinsic characterization of holonomic fluids, involving only the unit velocity, is given, showing that in spite of its dynamical appearance the notion of holonomic fluid is a kinematical notion. The relations between holonomic and thermodynamic perfect fluids are studied.
Lorentzian Comments on Stokes Parameters
2003
The popular Stokes statements about polarized light are interpreted in a Minkowskian language using a Lorentzian representation for the Stokes parameters and the degree of polarization. The evolution equations for Stokes parameters on a curved space-time are obtained using the parallel transport of the polarization vector along a null geodesic. The interest of these equations in Astrophysics and Relativistic Cosmology is outlined.
"Table 5" of "Search for new phenomena in the WW to l nu l' nu' final state in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector"
2012
Observed and predicted W+W- transverse mass distribution in the E-MU channel. Also tabulated are the predictions for a RS graviton of mass 1000 GeV and a bulk RS graviton with mass 600 GeV.
How to interpret black hole entropy?
1998
We consider a possibility that the entropy of a Schwarzschild black hole has two different interpretations: The black hole entropy can be understood either as an outcome of a huge degeneracy in the mass eigenstates of the hole, or as a consequence of the fact that the interior region of black hole spacetime is separated from the exterior region by a horizon. In the latter case, no degeneracy in the mass eigenstates needs to be assumed. Our investigation is based on calculations performed with Lorentzian partition functions obtained for a whole maximally extended Schwarzschild spacetime, and for its right-hand-side exterior region. To check the correctness of our analysis we reproduce, in th…
Relativistic Positioning Systems: Numerical Simulations
2014
The motion of satellite constellations similar to GPS and Galileo is numerically simulated and, then, the region where bifurcation (double positioning) occurs is appropriately represented. In the cases of double positioning, the true location may be found using additional information (angles or times). The zone where the Jacobian, J, of the transformation from inertial to emission coordinates vanishes is also represented and interpreted. It is shown that the uncertainties in the satellite world lines produce positioning errors, which depend on the value of |J|. The smaller this quantity the greater the expected positioning errors. Among all the available 4-tuples of satellites, the most app…
The galaxy power spectrum take on spatial curvature and cosmic concordance
2020
The concordance of the $\Lambda$CDM cosmological model in light of current observations has been the subject of an intense debate in recent months. The 2018 Planck Cosmic Microwave Background (CMB) temperature anisotropy power spectrum measurements appear at face value to favour a spatially closed Universe with curvature parameter $\Omega_K<0$. This preference disappears if Baryon Acoustic Oscillation (BAO) measurements are combined with Planck data to break the geometrical degeneracy, although the reliability of this combination has been questioned due to the strong tension present between the two datasets when assuming a curved Universe. Here, we approach this issue from yet another point…
Correlation functions for a strongly coupled boson system and plane partitions.
2011
A quantum phase model is introduced as a limit for very strong interactions of a strongly correlated q -boson hopping model. The exact solution of the phase model is reviewed, and solutions are also provided for two correlation functions of the model. Explicit expressions, including both amplitude and scaling exponent, are derived for these correlation functions in the low temperature limit. The amplitudes were found to be related to the number of plane partitions contained in boxes of finite size.
Introduction to Part IV
2018
When looking at the early development of relativity theory, one finds an astonishing number of contributions by mathematicians, some of which deeply influenced the work of leading theoretical physicists. Within the context of special relativity, Hermann Minkowski’s writings come immediately to mind (Walter 2008). Klein and Hilbert followed Minkowski’s ideas from their infancy, and both pursued some of their consequences after the latter’s premature death in January 1909. Two other figures with close ties to Gottingen, Max Born and Arnold Sommerfeld, were both instrumental in elaborating Minkowski’s 4-dimensional approach for physicists (Walter 2007). Born had been Minkowski’s assistant for …