Can stringy physics rescue the universe from a catastrophic transformation?

[Admin]

A new understanding inspired by string theory shows that our universe may be more stable than we previously thought.

Can stringy physics rescue the universe from a catastrophic transformation? : Read more

 

[rod]

Some comments in this article I noticed.

"Within the first microseconds of the Big Bang, the universe underwent a series of radical phase transitions. The four forces of nature — electromagnetism, gravity, the strong nuclear force and the weak nuclear force — were at one time unified into a single force. Physicists do not know the character or nature of this force, but they do know that it didn't last long."

My question. Where did the inflaton field come from in this early soup? Inflation very much depends upon the inflaton field existing in nature, presently not observed in nature. Without the inflaton field, the BB model horizon problem cannot be solved unless VSL is invoked perhaps.

"As the universe expanded and cooled, at first gravity split off from the remaining three. Then, the strong nuclear force became independent. Finally, the last two forces to split were electromagnetism and the weak nuclear force. That last splitting is actually within experimental reach: Within our largest particle accelerators, we can recreate the conditions of the early universe and achieve the energies needed to (briefly) recombine those two forces."

My observation. The origin of gravity is not explained, it seems assumed for the split to take place. The description here needs to be shown relative to the Planck time and Planck length, so we have some plain language statements to ponder with published values. This looks like a pre-inflation period described without such referencing to compare.

"The authors of the new paper studied a version of string theory that included nonlocal effects — which means strings in one region of space can seemingly instantaneously affect strings in another part of space despite their distance. (If you're wondering how radical an idea this is, it’s not that far-fetched: the phenomenon of quantum entanglement is also nonlocal.)"

My observation. I remember my Einstein readings. Special Relativity says there is no such thing as an *instantaneous action at a distance* force in nature. Yet here we read about such a force apparently in the paradigm used to explain the origin of the universe. In the BB model, we do have this force acting across distance instantly because 4D space is created everywhere at the moment of the BB event postulated.

"This is still extremely speculative physics, but at least it can provide a measure of comfort while we continue to understand the fundamental workings of the universe."

I concur here.

 

[rod]

Reference paper cited, Fate of the false vacuum in string-inspired nonlocal field theory, https://arxiv.org/abs/2203.04438, 08-March-2022.

"In this article, we study Coleman bounce in weakly nonlocal theories which are motivated from string field theory. The kinetic term is extended via an infinite series of high-order derivatives, which comes into play at an energy scale M, without introducing any new states or ghosts in the mass spectrum. We calculate the bubble nucleation in thin-wall approximation, treating the system in semi-classical manner. We find that the effect of nonlocal scale M in the theory is to suppress the vacuum tunneling rate from false to true vacuum compared to the standard local bouncing scenario. Likewise, we show that as we move further away from the bubble wall, the effects of nonlocality gets reduced and this suppression is significant only around the wall of the nucleated bubble. From our investigations, we conclude that the main effect is due to the fact that the nonlocality smears the solution of the local bubble profile. However, the energy of the bubble wall remains unaffected by the microscopic nonlocal behavior of the theory in the thin-wall approximation. We also discuss the cases for Lee-Wick theories and applications of our result to cosmology."

My note. The 22-page PDF cited has 3 references to Planck. "1 In local QFT, renormalization leads to ultraviolet (UV) divergences, which in the Standard Model (SM) of particle physics, a similar issue infamously known as the hierarchy problem where the Electroweak (EW) scale or the Higgs mass and Planck scale (Mpl) are separated by 18 orders-of-magnitude apart leading to huge fine-tuning in the SM [36] which for example needs several new particles at the or near the EW scale, like in supersymmetry (SUSY) etc. but no new physics results from the Large Hadron Collider (LHC) has been obtained, so alternative solutions are actively being pursued."

My note, here is another reference to Planck indicating the new physics is working below the Planck scale. "2 Short review: String-inspired nonlocal scalar field theory Typically, the action for the string-inspired nonlocal theory given by [33, 97]:.., m is the mass of the scalar particle, and M is the energy scale of the nonlocality which is usually taken to be below the Planck scale."

This does not surprise me. In December 2013, Alan Guth published a report on inflation where the scale for the universe maps 10^-53 m to 1 m size today using inflation, so sub-Planck scale universe described now to explain the origin of the universe we see today. I note what the 22-page paper reported, "are separated by 18 orders-of-magnitude apart leading to huge fine-tuning in the SM". More fine-tuning problems appear apparently to explain the origin of the universe along with new physics operating below the Planck scale and a postulated instantaneous action-at-a distance force working in nature during the early universe moments.

This is cool physics and something for me to chew on and ponder when it comes to how science explains the origin of the universe, I observe using my telescopes from my backyard