Would you like to know about string theory?

[Robert W]

Years back, I purchased Brian's Book about String Theory. Most won't be able to discuss it, but to help you out if you think about it, watch him explain it to you. After this, let the forum know if he persuaded you?

 

[John Edgar Slow Horses]

Can you? I could not follow Jim Parsons as Dr. Sheldon Cooper on it.

 

[Robert W]

Can you? I could not follow Jim Parsons as Dr. Sheldon Cooper on it.

I have yet to finish Greene's Book. Greene was once talking a lot about String Theory.

 

[scruffy]

There's not just one string theory, there are many.

The most popular one seems to revolve around the Calabi-Yau construction, but there are other topologies that will work.

Also in the game are discrete theories, mostly at the Planck scale. I like some of these, especially the ones based on information. The idea is a "bit" is an exchange of information - if there is no exchange then the result is what appears "to us" to be entanglement.

Calabi-Yau has a problem now that entanglement and gravity have been shown to be empirically orthogonal. But I'm not an expert, maybe someone can show us how it might work.

 

[ReinyDays]

Do we have a reason to believe there is some basic indivisible unit of existence ... like the string ... or could it be "turtles all the way down" ... and why is it important? ...

House cats can't tell time, so they use a spacial fourth dimension ... whereas timing is essential for human reproduction so we use time as a fourth dimension ... electromagnetism needs only two dimensions, one linear and one rotational ...

Alice had asked the Cheshire Cat to stop blinking in-and-out ... so it slowly backed up along the w-axis, until only it's grin remained ... 'I've often seen a cat without a grin,' thought Alice 'but a grin without a cat! It's the most curious thing i ever saw in my life!' ...

 

[Cellblock2429]

Years back, I purchased Brian's Book about String Theory. Most won't be able to discuss it, but to help you out if you think about it, watch him explain it to you. After this, let the forum know if he persuaded you?

/----/ My cat's understanding of string theory.

 

[Robert W]

/----/ My cat's understanding of string theory.
View attachment 974252

Good post. Actually after listening to Brian Greene, one top String Theory scientist, talk to other experts on this, he says few are persuaded it makes sense.

 

[Robert W]

Do we have a reason to believe there is some basic indivisible unit of existence ... like the string ... or could it be "turtles all the way down" ... and why is it important? ...

House cats can't tell time, so they use a spacial fourth dimension ... whereas timing is essential for human reproduction so we use time as a fourth dimension ... electromagnetism needs only two dimensions, one linear and one rotational ...

Alice had asked the Cheshire Cat to stop blinking in-and-out ... so it slowly backed up along the w-axis, until only it's grin remained ... 'I've often seen a cat without a grin,' thought Alice 'but a grin without a cat! It's the most curious thing i ever saw in my life!' ...

That is amusing. String Theory attracted me long ago because of the quest to figure out creation of all things. It is about the tiniest items imaginable that are in all things in existence. It makes sense.

 

[scruffy]

That is amusing. String Theory attracted me long ago because of the quest to figure out creation of all things. It is about the tiniest items imaginable that are in all things in existence. It makes sense.

I dunno... somehow packets make more sense than strings.

Packets in a field are intuitive, strings in a field are weirdo.

 

[ReinyDays]

I dunno... somehow packets make more sense than strings.

Packets in a field are intuitive, strings in a field are weirdo.

Why? ... why can't things be divisible? ... what are "packets" or "strings" made of? ... and more importantly, what laboratory experiment can we perform to demonstrate their existence? ...

Isn't this just philosophy? ... is there some phenomena this theory explains better than any other, or it this alchemy by a different name? ... fields operate as second-order tensors ... why couldn't these packets behave as higher ordered tensors? ... if we can have 26 dimensions, why can't we have 26 indexes? ...

Can these packets even be added together? ... or maybe our math doesn't work at all at this level ...

 

[Robert W]

Why? ... why can't things be divisible? ... what are "packets" or "strings" made of? ... and more importantly, what laboratory experiment can we perform to demonstrate their existence? ...

A video I watched mentioned that the test of this will or has happened at CERN.

POSTED BY MATT STRASSLER​

ON 09/17/2013
Over the weekend, someone said to me, breathlessly, that they’d read that “Results from the Large Hadron Collider [LHC] have blown string theory out of the water.”
Good Heavens! I replied. Who fed you that line of rubbish?!
Well, I’m not sure how this silliness got started, but it’s completely wrong. Just in case some of you or your friends have heard the same thing, let me explain why it’s wrong.
First, a distinction — one that is rarely made, especially by the more rabid bloggers, both those who are string lovers and those that are string haters. [Both types mystify me.] String theory has several applications, and you need to keep them straight. Let me mention two.

1. Application number 1: this is the one you’ve heard about. String theory is a candidate (and only a candidate) for a “theory of everything” — a silly term, if you ask me, for what it really means is “a theory of all of nature’s particles, forces and space-time”. It’s not a theory of genetics or a theory of cooking or a theory of how to write a good blog post. But it’s still a pretty cool thing. This is the theory (i.e. a set of consistent equations and methods that describes relativistic quantum strings) that’s supposed to explain quantum gravity and all of particle physics, and if it succeeded, that would be fantastic.
2. Application number 2: String theory can serve as a tool. You can use its mathematics, and/or the physical insights that you can gain by thinking about and calculating how strings behave, to solve or partially solve problems in other subjects. (Here’s an example.) These subjects include quantum field theory and advanced mathematics, and if you work in these areas, you may really not care much about application number 1. Even if application number 1 were ruled out by data, we’d still continue to use string theory as a tool. Consider this: if you grew up learning that a hammer was a religious idol to be worshipped, and later you decided you didn’t believe that anymore, would you throw out all your hammers? No. They’re still useful even if you don’t worship them.

BUT: today we are talking about Application Number 1: string theory as a candidate theory of all particles, etc.
Now what’s so silly about this notion that the LHC has ruled out string theory is that the whole reason a lot of people hate string theory is that it doesn’t make any testable predictions! So obviously you can’t rule it out with current experiments… that would require testable predictions!

Did the LHC Just Rule Out String Theory?!

Over the weekend, someone said to me, breathlessly, that they’d read that “Results from the Large Hadron Collider [LHC] have blown string theory out of the water.” Good Heavens! I…

profmattstrassler.com

 

[ReinyDays]

A video I watched mentioned that the test of this will or has happened at CERN.

POSTED BY MATT STRASSLER​

ON 09/17/2013
Over the weekend, someone said to me, breathlessly, that they’d read that “Results from the Large Hadron Collider [LHC] have blown string theory out of the water.”
Good Heavens! I replied. Who fed you that line of rubbish?!
Well, I’m not sure how this silliness got started, but it’s completely wrong. Just in case some of you or your friends have heard the same thing, let me explain why it’s wrong.
First, a distinction — one that is rarely made, especially by the more rabid bloggers, both those who are string lovers and those that are string haters. [Both types mystify me.] String theory has several applications, and you need to keep them straight. Let me mention two.

1. Application number 1: this is the one you’ve heard about. String theory is a candidate (and only a candidate) for a “theory of everything” — a silly term, if you ask me, for what it really means is “a theory of all of nature’s particles, forces and space-time”. It’s not a theory of genetics or a theory of cooking or a theory of how to write a good blog post. But it’s still a pretty cool thing. This is the theory (i.e. a set of consistent equations and methods that describes relativistic quantum strings) that’s supposed to explain quantum gravity and all of particle physics, and if it succeeded, that would be fantastic.
2. Application number 2: String theory can serve as a tool. You can use its mathematics, and/or the physical insights that you can gain by thinking about and calculating how strings behave, to solve or partially solve problems in other subjects. (Here’s an example.) These subjects include quantum field theory and advanced mathematics, and if you work in these areas, you may really not care much about application number 1. Even if application number 1 were ruled out by data, we’d still continue to use string theory as a tool. Consider this: if you grew up learning that a hammer was a religious idol to be worshipped, and later you decided you didn’t believe that anymore, would you throw out all your hammers? No. They’re still useful even if you don’t worship them.

BUT: today we are talking about Application Number 1: string theory as a candidate theory of all particles, etc.
Now what’s so silly about this notion that the LHC has ruled out string theory is that the whole reason a lot of people hate string theory is that it doesn’t make any testable predictions! So obviously you can’t rule it out with current experiments… that would require testable predictions!

Did the LHC Just Rule Out String Theory?!

Over the weekend, someone said to me, breathlessly, that they’d read that “Results from the Large Hadron Collider [LHC] have blown string theory out of the water.” Good Heavens! I…

profmattstrassler.com

Did you work through all this? ... did you see the part where this can't be demonstrated, and has no real world application? ...

Matt Strassler is entitled to stretch things as far as commercially available ... it's how he makes money ... the example cited isn't about strings, it's about better computational analysis of existing particle theory (which does NOT include strings) ...

Just because people will pay to hear this stuff doesn't make it true ...

 

[Robert W]

Did you work through all this? ... did you see the part where this can't be demonstrated, and has no real world application? ...

Yes I did, to grasp what happened. Did you know why it can't be demonstrated? It is well known that string theory is still in the testing stage. When it came up, I was excited.

 

[ReinyDays]

Yes I did, to grasp what happened. Did you know why it can't be demonstrated? It is well known that string theory is still in the testing stage. When it came up, I was excited.

It can't be tested ... or at least the form of string theory discussed in the "example" link ... and that is an important distinction ... The Scruff is right, there's as many different forms of string theory as there are string theorists ...

 

[Robert W]

It can't be tested ... or at least the form of string theory discussed in the "example" link ... and that is an important distinction ... The Scruff is right, there's as many different forms of string theory as there are string theorists ...

Now it can't be tested. But forever it can't be? We actually agree.