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When a supernova explodes, most of its energy is released in a shell of relativistic neutirnos which changes the surrounding geometry. We calculate the potentially observable responses to such a change in both pulsar scintillation and conventional interferometers. In both cases, the responses are permanent changes due to such a transient event. This is by-definition a memory effect. In addition to the transverse component in the usual gravitational memory (Christodolou effect) effect, it also has a longitudinal component. Furthermore it is different from the Christodolou effect as the transverse component of this memory effect also has a term that grows with time.
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We show that when a supernova explodes, a nearby pulsar signal goes through a very specific change. The observed period first changes smoothly, then is followed by a sudden change in the time derivative. A stable millisecond pulsar can allow us to measure such an effect. This may improve our measurement of the total energy released in neutrinos and also the orientation of the supernova-pulsar system.
We study high-energy neutrino emissions from tidal disruption remnants (TDRs) around supermassive black holes. The neutrinos are produced by the decay of charged pions originating in ultrarelativistic protons that are accelerated there. In the standard theory of tidal disruption events (TDEs), there are four distinct phases from debris circularization of stellar debris to super- and sub-Eddington to radiatively inefficient accretion flows (RIAFs). In addition, we consider the magnetically arrested disk (MAD) state in both the super-Eddington accretion and RIAF phases. We find that there are three promising cases to produce neutrino emissions: the super-Eddington accretion phase of the MAD state and the RIAF phases of both the non-MAD and MAD states. In the super-Eddington MAD state, the enhanced magnetic field makes it possible to accelerate the protons to $E_{p,max}~0.35 PeV (M_bh/10^{7.7}M_odot)^{41/48}$ with the other given appropriate parameters. The neutrino energy is then $E_{ u,pk}~67 TeV (M_bh/10^{7.7}M_odot)^{41/48}$ at the peak of the energy spectrum. For $M_bhgtrsim10^{7.7} M_odot$, the neutrino light curve is proportional to $t^{-65/24}$, while it follows the standard $t^{-5/3}$ decay rate for $M_bh<10^{7.7} M_odot$. In both cases, the large luminosity and characteristic light curves diagnose the super-Eddington MAD state in TDEs. In the RIAF phase of the non-MAD state, we find $E_{p, max}~0.45 PeV (M_bh/10^7M_odot)^{5/3}$ and $E_{ u,pk}~0.35 PeV (M_bh/10^7M_odot)^{5/3}$, and its light curve is proportional to $t^{-10/3}$. This indicates that one can identify whether the existing RIAFs are the TDE origin or not. TDRs are potentially a population of hidden neutrino sources invisible in gamma rays.
We study the empirical realization of the memory effect in Yang-Mills theory with an axion-like particle, especially in view of the classical vs. quantum nature of the theory. We solve for the coupled equations of motion iteratively in the axionic contributions and explicitly display the gauge invariant effects in terms of field strengths. We apply our results in the context of heavy ion collisions, in the thin nuclear sheet limit, and point out that a probe particle traversing radiation train acquires a longitudinal null memory kick in addition to the usual transverse kick.
We study the empirical realisation of the memory effect in Yang-Mills theory, especially in view of the classical vs. quantum nature of the theory. Gauge invariant analysis of memory in classical U(1) electrodynamics and its observation by total change of transverse momentum of a charge is reviewed. Gauge fixing leads to a determination of a gauge transformation at infinity. An example of Yang-Mills memory then is obtained by reinterpreting known results on interactions of a quark and a large high energy nucleus in the theory of Color Glass Condensate. The memory signal is again a kick in transverse momentum, but it is only obtained in quantum theory after fixing the gauge, after summing over an ensemble of classical processes.
It has been speculated that Lorentz-invariance violation (LIV) might be generated by quantum-gravity (QG) effects. As a consequence, particles may not travel at the universal speed of light. In particular, superluminal extragalactic neutrinos would rapidly lose energy via the bremssthralung of electron-positron pairs (nu -> nu e+ e-), damping their initial energy into electromagnetic cascades, a figure constrained by Fermi-LAT data. We show that the two cascade neutrino events with energies around 1 PeV recently detected by IceCube -if attributed to extragalactic diffuse events, as it appears likely- can place the strongest bound on LIV in the neutrino sector, namely delta =(v^2-1) < O(10^(-18)), corresponding to a QG scale M_QG ~ 10^5 M_Pl (M_QG >~ 10^(-4) M_Pl) for a linear (quadratic) LIV, at least for models inducing superluminal neutrino effects (delta > 0).
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