The 'string theory landscape', referred to above by Bonsai, is 'the collection of possible false vacuum states'.
If our universe is in a false vacuum state it could decay to the more stable true vacuum state.
"In the new vacuum there are new constants of nature. After vacuum decay, not only is life as we know it impossible, so is chemistry as we know it." - Sidney Coleman & Frank De Luccia
Vacuum decay has been described as the ultimate ecological catastrophe!
If our universe is in a false vacuum state it could decay to the more stable true vacuum state.
"In the new vacuum there are new constants of nature. After vacuum decay, not only is life as we know it impossible, so is chemistry as we know it." - Sidney Coleman & Frank De Luccia
Vacuum decay has been described as the ultimate ecological catastrophe!
I expect that @Bonsai is particularly drawn to the KKLT mechanism that provides a possible theoretical explanation of the fact that the experimentally measured value of the cosmological constant is about a trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion times weaker than theory predicts.
When the accelerating expansion of the universe was discovered in 1998, Renata Kallosh said “Theoretical physics was upside down because of this experimental discovery. We had no explanation whatsoever.”
However, with the help of her three collaborators, she came up with the KKLT mechanism which is a solution of string theory that allows the existence of as many as 10^500 unique possible universes, each with a small cosmological constant.
According to this solution, our universe is an exception to the norm or, as Leonard Susskind put it, “In string theory, the Landscape is incredibly rich, and our universe lies in one of the rare, habitable, low-lying valleys.”
The full story is here: https://news.stanford.edu/2018/09/13/lambda-leads-way/
When the accelerating expansion of the universe was discovered in 1998, Renata Kallosh said “Theoretical physics was upside down because of this experimental discovery. We had no explanation whatsoever.”
However, with the help of her three collaborators, she came up with the KKLT mechanism which is a solution of string theory that allows the existence of as many as 10^500 unique possible universes, each with a small cosmological constant.
According to this solution, our universe is an exception to the norm or, as Leonard Susskind put it, “In string theory, the Landscape is incredibly rich, and our universe lies in one of the rare, habitable, low-lying valleys.”
The full story is here: https://news.stanford.edu/2018/09/13/lambda-leads-way/
🤣🤣🤣🤣🤣I read that bit too, but referred to the bit to which you hadn't referred!
This is where I have to ‘get off the bus’ so to speak.The 'string theory landscape', referred to above by Bonsai, is 'the collection of possible false vacuum states'.
If our universe is in a false vacuum state it could decay to the more stable true vacuum state.
"In the new vacuum there are new constants of nature. After vacuum decay, not only is life as we know it impossible, so is chemistry as we know it." - Sidney Coleman & Frank De Luccia
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Vacuum decay has been described as the ultimate ecological catastrophe!
We cannot with any degree of certainty explain precisely what allows an EM wave or photon if you prefer, or gravity waves, to propagate through a vacuum without invoking some sort of fantastical vacuum state energy densities, ephemeral fermions etc which all rest on a theory that within its bounds includes 10^nth other universes, of which ours we are to believe is an exception which at any instant could self-anhilate.
Doesn’t this sound like a religious text?
It’s no wonder people like Sabine Hossenfelder, and to some extent Ethan Seagal, question some of this stuff. Seagal just seems to steer clear of it and focus on the more practical aspects rather than stray into areas that at best are hypothetical.
I ended up a few weeks ago on a webpage that billed itself as a ‘higher mathematics’ site. In it they talk about doing higher mathematics for the sake of it ie it exists purely on its own and may not have practical implications but that’s ok. I really have a problem with doing math on auto pilot (quoting Leonard Susskind) and then pronouncing the end result as fact. This is where Einstein teaches everyone a lesson. Math is there to serve and support a process of logical deduction, surely not for us to fit a worldview around what it tells us?
String theorists are certain that they are practicing physicists.
However, as Einstein might have said to them, "Get off the bus and get on your bike"!
You may be interested in dipping into this lengthy article: https://www.sciencedirect.com/science/article/pii/S0039368121001023
Here's a relevant quote from the article:
Particle physicist Sabine Hossenfelder has been most explicit in expressing despair, for instance in the pages of Nature Physics: according to her, fundamental physics is facing a dearth of data and a bewildering plethora of theories, multiplying primarily by what attracts citations and funding. “The current practices in theory development signal a failure of the scientific method”, Hossenfelder believes. She contends that, while astrophysicists propose more and more candidates for dark matter or different models for inflation, “in the absence of good quality measures […] there is no evidence that a theory's fruitfulness correlates with its correctness.” While fashion dictates, objectivity is impaired: “social and cognitive biases” have produced “a serious systemic failure”.
For the record, I should make this correction:
The graviton is the field quantum in gravity while its supersymmetric partner the gravitino is the field quantum in supergravity.
It may sound more like magic than physics, but supersymmetry suggests that every particle in the Standard Model has a 'superpartner'.
Although there's no experimental evidence that superpartners exist, it doesn't stop the theorists talking of the selectron, squark, photino and gluino!
You can read more about supersymmetry and "Gravity's Twin" in this article: https://www.space.com/primordial-black-holes-giant-gravitinos
Steve aka system7 has just been discharged from Hospital! A crazy week.
But I am now feeling much better.
I had an autistic meltdown. Anyway good to be back. I am still full of librium tranqulisers.
Hope to be back on form soon. Thanks, everyone.
Life can be strange....
But I am now feeling much better.
I had an autistic meltdown. Anyway good to be back. I am still full of librium tranqulisers.
Hope to be back on form soon. Thanks, everyone.
Life can be strange....
Wait til you get old. I (73) bruise just from working with my arms & hands. No loss apparently. Old men have to stop taking Iron in vitamins because we do not bleed as often as our ancestors. Excess iron has bad health effects I read.Look at my left arm. Doctors did this in search of blood!
What a mess!!
Glad you are back. Science comments solicited.
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It sure is, but not as large as a 'cosmic bruise'!
An ancient collision of another bubble universe with ours may have left behind 'alien' material in the form of a 'cosmic bruise'.
Scientists say there is for evidence of an ancient collision in the form of a cold spot (circled in the above image) in the cosmic microwave background.
https://www.nbcnews.com/mach/science/cosmic-bruise-could-be-evidence-multiple-universes-ncna771076
Sorry about the recent off-topicness everyone. I am shortly off for some rest and recuperation after a very unpleasant autistic meltdown episode which ended me up in hospital for a week.
I shall be taking my notepad and calculator and maths book to crack this De Broglie wavelength and frequency problem (which @Galu raised) to my satisfaction...
Alas Sean Carroll's second volume is delayed until 14 May:
So I must just be patient. I think he has some videos currently available too. So that may help.
Looking forward to doing some good old Physics again. It'll be like old times! I have no idea what the computers are like at my impending retreat, I think they are all Apple tablets, not proper Linux PCs.
But whatever. A good Particle Physicist can cope with most technology. "I'll be back", as the Terminator famously said.
I shall be taking my notepad and calculator and maths book to crack this De Broglie wavelength and frequency problem (which @Galu raised) to my satisfaction...
Alas Sean Carroll's second volume is delayed until 14 May:
So I must just be patient. I think he has some videos currently available too. So that may help.
Looking forward to doing some good old Physics again. It'll be like old times! I have no idea what the computers are like at my impending retreat, I think they are all Apple tablets, not proper Linux PCs.
But whatever. A good Particle Physicist can cope with most technology. "I'll be back", as the Terminator famously said.
De Broglie wavelength figures heavily in the explanation of the operation of the Intelligent Chip, the most talked about audiophile device of twenty years ago. It also figures in how the CD laser works (quantum well, although that is not nearly as mysterious as the chip. For those too young to remember the Intelligent Chip was placed on top of a CD player, then the CD to be treated was inserted into the player and allowed to play for 2 seconds, during which time the CD was upgraded permanently. And when played it sounded like a remastered version.
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I know you are aware that there are two ways to assign a wavelength to an elementary particle.
- By using the speed of light we can construct the Compton wavelength (h/mc). This wavelength is independent of the velocity of the particle.
- By using the true momentum of the particle mv instead of mc we get the de Broglie wavelength (h/mv).
To confirm that statement: E = mc^2 = h f = h c/λ which gives λ = h/mc.
I believe the Compton wavelength of an electron is about 500 times smaller than the de Broglie wavelength of a 1 eV electron.
So where does that get us with my hypothesis that an elementary particle or 'quantum wave packet' couples its own vibrations to those of the Higgs field and that the strength of that coupling depends on the quantum wavelength of the elementary particle?
My guess - absolutely nowhere!
However, enjoy your R & R.
In
😊
Interesting- what will Sabine make of it? If it turns out to be another universe, it will be one of the most spectacular predictions of theoretical physics.It sure is, but not as large as a 'cosmic bruise'!
An ancient collision of another bubble universe with ours may have left behind 'alien' material in the form of a 'cosmic bruise'.
View attachment 1290330
Scientists say there is for evidence of an ancient collision in the form of a cold spot (circled in the above image) in the cosmic microwave background.
https://www.nbcnews.com/mach/science/cosmic-bruise-could-be-evidence-multiple-universes-ncna771076
😊