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Calculating characteristic timescales for environmental decoherence in the presence of thermal gravitons Public Deposited

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  • Different models show the effects of environmental decoherence on a quantum system due to various environments of interest. One important quantity within these models is the decoherence time, which tells us how quickly environments wash away the coherence of local measurements. We can describe this effect as the quantum system becoming entangled with the environment, whereupon any superposition that existed at the level of the system becomes a global phenomenon. In the following work, we make use of the scattering model first introduced by Joos and Zeh in 1973, and later improved through the work of Gallis, Fleming, Adler, and Hornberger to find decoherence times of a point mass, dielectric sphere. We will do this in the presence of two different graviton environments first, a cosmic gravitational wave background (CGWB), and later a flux of gravitons emanating from a stellar core. We compare these same quantities in the corresponding photon environments which include the cosmic microwave background (CMB) and photons from stellar cores. Results show decoherence times much longer than those corresponding to photons. This is consistent with the known fact that gravity being the weakest of the four fundamental forces weakly interacts with matter, especially for smaller less massive objects. We then show this weak interaction manifests itself in decoherence times and gives us an idea for the numbers involved with gravitational interactions and provides a better intuition for the scale at play. Furthermore, this exploration allows us to explore divergence in the differential cross section for gravitons scattering off the gravitational field of a point mass. This issue differs from the corresponding problem in Coulomb scattering (which exhibits the same divergence behavior) since gravity only deals with mass and involves no differences in charge. This makes finding a finite result for the differential cross section of gravitons an interesting problem and we present one solution below.
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