First collisions at the LHC with unprecedented Energy! (Ask a particle physisicist)

[Alex K]

You ask some excellent questions, Pyrrho. I'll have to think about it...

[Alex K]

Okay.  So what are the laws of nature?  Or can you recommend a short book?  Would something like this be a good choice?  If not, what do you recommend that is on that reading level?  Of course, you may feel free to just explain it all here.

While the book you quote is lovely, it has a somewhat different focus: telling you how all kinds of phenomena are described using the appropriate physics approximations, from Newton to modern. What I'd have in mind is something slightly different: a book that simply describes the state of the art theory in good detail. Personally I haven't seen many books that do a good job (they usually put more speculative sexy stuff and don't spend enough time explaining the actual status quo, or have a focus on cosmology because it's sexy), but this looks good:

http://www.amazon.com/The-Theory-Almost-...0452287863

Of course, I would recommend my own work, but it is in German, and the first part will only come out in 4 weeks time.

[Pyrrho]

Okay.  So what are the laws of nature?  Or can you recommend a short book?  Would something like this be a good choice?  If not, what do you recommend that is on that reading level?  Of course, you may feel free to just explain it all here.

While the book you quote is lovely, it has a somewhat different focus: telling you how all kinds of phenomena are described using the appropriate physics approximations, from Newton to modern. What I'd have in mind is something slightly different: a book that simply describes the state of the art theory in good detail. Personally I haven't seen many books that do a good job (they usually put more speculative sexy stuff and don't spend enough time explaining the actual status quo, or have a focus on cosmology because it's sexy), but this looks good:

http://www.amazon.com/The-Theory-Almost-...0452287863

Of course, I would recommend my own work, but it is in German, and the first part will only come out in 4 weeks time.

Why don't you translate your book into English and publish it in English as well?  Wouldn't it be more likely to sell more copies worldwide in English than in German?  (If you feel like you must thank me for this idea, you can pay me a percentage of the royalties you get for the English version.)

[Alex K]

I'll talk to the publisher as soon as it's done. But actually I must correct myself. What comes out now is the condensed version which is kind of a crash course, a full length book fleshing everything out in detail is planned to follow.

[Pyrrho]

---

Okay.  So what are the laws of nature?  Or can you recommend a short book?  Would something like this be a good choice?  If not, what do you recommend that is on that reading level?  Of course, you may feel free to just explain it all here.

While the book you quote is lovely, it has a somewhat different focus: telling you how all kinds of phenomena are described using the appropriate physics approximations, from Newton to modern.

---

What I'd have in mind is something slightly different: a book that simply describes the state of the art theory in good detail. Personally I haven't seen many books that do a good job (they usually put more speculative sexy stuff and don't spend enough time explaining the actual status quo, or have a focus on cosmology because it's sexy), but this looks good:

http://www.amazon.com/The-Theory-Almost-...0452287863

Of course, I would recommend my own work, but it is in German, and the first part will only come out in 4 weeks time.

Before I order this book and read it, how will doing so improve my life?  What will I gain from this experience?  And is that really worth more than a bottle of decent wine?  That seems pretty hard to believe...

[Alex K]

You are obviously not in the state of mind to appreciate these matters. I suggest you drink a bottle of red first and then see whether you feel like contemplating the fundamental questions.

[Pyrrho]

You are obviously not in the state of mind to appreciate these matters. I suggest you drink a bottle of red first and then see whether you feel like contemplating the fundamental questions.

That is the most sensible thing I have ever read that was written by a physicist.  So I have decided to take your advice and have already ordered the book.

[JuliaL]

If it's too much either I explained it badly or you're too ambitious
Come on! Post the questions!

You have given me insight into the Dunning Kruger Syndrome.  I had always simplified this as, "Stupid people don't know they're stupid because... they're stupid." 
That was a wrong way to look at it.  Wikipedia says,
 

Dunning–Kruger effect is a cognitive bias wherein relatively unskilled individuals suffer from illusory superiority, mistakenly assessing their ability to be much higher than is accurate....Their research also suggests that conversely, highly skilled individuals may underestimate their relative competence, erroneously assuming that tasks that are easy for them also are easy for others.

You are clearly in the highly skilled group.

More questions?
Well,  I'll risk it.

Over the weekend, I (had) read (to me (MP3s)) R.P. Feynman's collected short works, The Pleasure of Finding Things Out in which he showed himself similarly self deprecating.  For example, and paraphrasing, in his acceptance speech, he said something like, "Why are you giving me the Nobel, I just cleaned up the existing model by shoveling the infinities under the carpet."

The book was not very clear in describing the existing model and how Feynman's quantum electrodynamics fixed it.
Could you clarify?  Imagine you're explaining this to your dog, or hamster.  Short, simple words are best.

Previously, you answered a question I had about the pentaquark recently discovered (created?)

BUT: the QCD interaction between the gluon and quark fields unfortunately becomes so strong at these low energies that talking about individual gluons doing this or that makes no sense any more.

The question I had was in interpreting your answer.   In my mind, a low energy condition should make it easier, not harder to separate and identify individual particles.
This got me into Wikipedia and into QCD -> area rule and gluon containment -> lots more things I didn't understand -> I give up!
I think my education is quite a few decades obsoleted with respect to gluons and quarks.
I do remember the wave equation, the square of which, at a specific place, is a probability density for finding an electron(?) there.
Are the "quark and gluon fields" superimposed on this? separate? components of?

More recently you wrote:

It doesn't look like it. In quantum field theory, there is a famous three line proof that experiments separated by more than light speed cannot affect each other measurably.

I understand experiments being separated in space or time.
But separated by a speed?  Is that that Minkowski spacetime thing again?
Is this the same thing as not being in each other's light cones?  I sort of get that.

Thank you for your continued patience.

[Alex K]

JuliaL

Haha, yes, I'm like Feynman

Anyways... So, in reverse order.

I simply meant just that, the two experiments take place in places at times that one can not send a light beam from.the earlier to the later one, i.e. they are not in each other's light cone as you say more correctly.

QCD: indeed, QCD has the curious property that the interaction becomes stronger at large distances/low energies, which makes studying it much harder. Why QCD has this property is hard to explain visually. Possibly because I don't understand it well enough. Maybe this: the larger the distance and the longer one waits, the more time the virtual particles between say two quarks have to build up force. It indeed ends up looking like a sticky mass of glue between them. Fun fact: string theory was originally invented to describe those "rubber bands", before it wqs completely repurposed and put in 10 spacetime dimensions.

The question about the relation between quantum wave functions and fields is not specific to QCD, but generally to quantum field theory. It is a very technical question that I struggle answering without maths. Ok, field and wave function are somewhat different categories. A wave function is a function that assigns the (sqrt of) probabilities to a place and time

f(x;t)

Strictly speaking that is just the 1-particle wave function. If there are three particles, say, the wave function is

f(x1,x2,x3;t)

It assigns a probability to a combination of three places for the respective particles. It becomes more complex very quickly for many particles, and impossible to visualize. Now, a field is a mathematical object

F(x,t)

which always depends on just one coordinate. It *very roughly speaking* tells you how to make one more particle at place x if you already have n of them, and how the probability wave function changes in going from n to n+1 particles.

f(x1,x2.... xn, x_n+1) = F(x_n+1)( f(x1,...xn) )

As such it encodes the behavior of an arbitrary collection of particles of the theory, but not the detailed state in which the system is in. Sigh, such an inadequate answer.

[JuliaL]

QCD: indeed, QCD has the curious property that the interaction becomes stronger at large distances/low energies, which makes studying it much harder. Why QCD has this property is hard to explain visually. Possibly because I don't understand it well enough. Maybe this: the larger the distance and the longer one waits, the more time the virtual particles between say two quarks have to build up force. It indeed ends up looking like a sticky mass of glue between them.

I need to buy a better intuition plug-in.

If the interaction is stronger at larger distances, shouldn't the amount of work needed to remove the particles (quarks?) away from one another make the far apart particle condition one of higher (internal) energy? Or isn't the interaction one of binding the particles together? I'm confused about what high/low energy means in this context.