Session E13: Quantum Gravity II

On the Quantization of Plane Gravitational Waves: Flat space considerations

In a (1+1)-dimensional midi-superspace model for gravitational plane waves, a flat space-time condition will be discussed Solutions to a straightforward regularization of these constraints for flat space have diverging geometric expectation values. Physically acceptable solutions in the kinematic Hilbert space of a single atom of geometry are obtained. The expectation values and moments of the ``flat space" constraint and geometric quantities are found, showing that these states provide possible kinematic states for flat space with fluctuations. Progress toward solutions of the scalar constraint will be discussed as time allows.   

Graybody Factors and Infrared Divergences

A method of computing the gray-body factors for static spherically symmetric and BEC acoustic black holes using a Volterra integral equation is given. The results are used to investigate infrared divergences in the particle number, two-point function, point-split stress-energy tensor and density-density correlation function. Infrared divergences in the particle number and two-point function occur if the gray-body factor approaches a nonzero constant in the zero frequency limit, as happens for Schwarzschild-de Sitter black holes and BEC acoustic black holes. However, no infrared divergences occur in the point-split stress-energy tensor or the density-density correlation function.   

Two-point function for a BEC acoustic black hole

The two point function for phonons for a Bose-Einstein condensate, BEC, with effectively one spatial dimension is calculated using the formalism of quantum field theory in curved space. The BEC has a constant flow velocity and the speed of sound is modified in such a way as to create regions of subsonic and supersonic flow. Excitations of the modes occur in the transverse direction and the direction of flow. The mode equation can be written as a wave equation with a potential in a 1+1 dimensional spacetime. Excitations in the transverse direction contribute a mass-like term to this equation. An approximation is used for this term which allows the mode equation to be solved analytically which greatly simplifies the calculation.   

The effect of Quantum Gravity on astrophysical neutrino flavor observables

At the quantum level, an interaction of a neutrino with a graviton may trigger the collapse of the neutrino flavor eigenstate to a neutrino mass eigenstate. I will present that such an essentially quantum gravity effect may have strong consequences for neutrino oscillation phenomena in astrophysics due to the relatively large scattering cross section of relativistic neutrinos off massive sources of gravitational fields (the case of gravitational Bethe-Heitler scattering). This results in a new technique for the indirect detection of gravitons by measuring the flavor composition of astrophysical neutrinos.   

Casimir effect in a quantum space-time

We study the Casimir effect for large spherical shells. Instead of a continuous background space-time, we consider a recent exact solution of a spherically symmetric vacuum space-time in loop quantum gravity, where the effective geometry becomes discrete. The quantum space-time naturally regularizes the quantum field theory and the correct result for the Casimir effect is obtained without regularization nor renormalization. This shows that quantum geometry can help to deal with the infinities of quantum field theory.   

A New Physical Meaning of Sommerfeld Fine Structure Constant

Identifying physical space or Casimir vacuum as a \textit{compressible} tachyon fluid, Planck compressible ether, leads to stochastic definitions of Planck h $=$ m$_{k}$ \textless $\lambda_{k}$\textgreater c and Boltzmann k $=$ m$_{k}$ \textless $\nu_{k}$\textgreater c constants, finite photon mass m$_{k}=$ (hk/c$^{3})^{1/2}$, amu $=$ m$_{k}$c$^{2}=$ (hkc)$^{1/2}$, and modified Avogadro-Loschmidt number N$_{o}=$ 1/(hkc)$^{1/2}=$ 6.03766 x10$^{23}$ mole$^{-1}$. Thus, Lorentz-FitzGerald contractions now result from compressibility of physical space and become \textit{causal} (Pauli) in accordance with Poincar\'{e}-Lorentz dynamic theory of relativity as opposed to Einstein kinematic theory of relativity. At thermodynamic equilibrium h$_{e}=$ m$_{e}$ \textless $\lambda_{e}$\textgreater v$_{e}=$ h$_{k} = $ m$_{k}$\textless $\lambda_{k}$\textgreater c $=$ h, Compton wavelength can be expressed as $\lambda_{c}=$ h/m$_{e}$c $=$ (v$_{e}$/c)h\textless $\lambda_{e}$\textgreater /(m$_{e}$\textless $\lambda_{e}$\textgreater v$_{e}) \quad =\alpha \lambda_{e}$. Hence, Sommerfeld fine structure constant $\alpha $ is identified as the ratio of electron to photon speeds $\alpha =$ e$^{2}$/(2$\varepsilon_{o}$hc) $=$ v$_{e}$/c $=$ 1/137.036. The mean thermal speed of electron at equilibrium with photon gas is v$_{e}=$ 2.187640x10$^{6}$ m/s and its de Broglie wavelength is $\lambda_{e}=$ 3.3250x10$^{-10}$ m. Also, electron kinetic energy for oscillations in two directions \textless x$+$\textgreater and \textless x-\textgreater or $\varepsilon_{e}=$ h$\nu_{e}=$ m$_{e}$v$_{e}^{2}=$ kT$_{e}$ results in electron temperature T$_{e}=$ 3.15690x10$^{5}$ K.   

Gravitational radiation as radiation same level of electromagnetic and its generation in pulsed high-current discharge. Theory and experiment.

The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on theoretically proved and experimentally confirmed fact of existence of stationary states of an electron in its gravitational field characterized by the gravitational constant K $=$ 10$^{42}$G (G is the Newtonian gravitational constant) and unrecoverable space-time curvature $\Lambda $. This paper gives an overview of the authors' works, which set out the relevant results. Additionally, data is provided on the broadening of the spectra characteristic radiation. The data show that this broadening can be explained only by the presence of excited states of electrons in their gravitational field. What is more, the interpretation of the new line of X-ray emission spectrum according to the results of observation of MOS-camera of XMM-Newton observatory is of interest. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational radiation spectrum such that amplification of gravitational radiation may take place only in multiple-charge ion high-temperature plasma.   

Graviton as a Grand United Gauge Boson

To any type of charge corresponds a kind of inertial mass. Such a mass-charge duality explains the availability in the neutrino of the naturally united rest mass and charge equal to all its mass and charge consisting of the electric, weak, strong and a range of other the innate components. From their point of view, we discuss a new theory of a grand unification. In this theory, the gravitational field is a naturally united field of the unified system of the most diverse combinations of the electric photons, magnetic monophotons, weak bosons and the strong gluons where the four pairs of forces of a different nature are united. Some consequences and laboratory confirmations of the discussed theory have been listed, in which graviton is predicted as a grand united gauge boson. Therefore, the gravitons constitute a natural light testifying in favor of gravitational force. They show that to each type of light corresponds a kind of force. Thereby, the suggested field theory that unites all gauge bosons in gravitons gives the possibility to directly look on the nature of gravitational matter elucidating the interratio of intragraviton forces and the problem of elementary particle fundamental symmetries.