I Vacuum up-tunneling with high-energy events?

AI Thread Summary
Sean Carroll argues against the occurrence of vacuum up-tunneling in the universe, suggesting it is only feasible during the universe's early heated moments, after which the rate drops to zero. High-energy cosmic rays, which are massive particles, were initially thought to not be redshifted by cosmic expansion, potentially allowing them to excite vacuum energy. However, it has been clarified that cosmic rays can indeed experience redshift. This raises questions about the possibility of cosmic rays exciting the vacuum in the future and whether any form of energy exists that would not be redshifted and could lead to vacuum up-tunneling. The discussion ultimately questions the feasibility of vacuum excitation under current cosmic conditions.
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Vacuum up-tunneling with high-energy events?
I was reading these papers by Sean Carroll (https://arxiv.org/abs/1405.0298; https://arxiv.org/abs/1505.02780) in which, among other things, he argues against vacuum up-tunneling occurring in the universe. He only acknowledged that it would be possible in the first moments of the universe while it was heated, but after that the rate goes to zero.

Meanwhile, vacuum energy can be excited by high energetic events like high energy cosmic rays. I thought that cosmic rays, being massive particles, were not redshfited by the expansion of the universe as photons are; therefore, if cosmic rays were produced in the big bang or as a result of a previous false vacuum decay, then these particles could eventually excite the vacuum, essentially causing an up-tunneling.

However, apparently cosmic rays can get redshifted as well (https://astronomy.stackexchange.com...alent-of-the-red-shift-effect-for-cosmic-rays). Then, is it impossible that cosmic rays may excite the vacuum in the future? Is there any kind of energy that does not get "redshifted" and therefore could cause an up-tunneling of the vacuum? Is it really utterly impossible to excite the vacuum?
 

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