Locrian

Those are not examples of physics nobels

I think physics nobel's are always awarded for discoveries for which there has been plenty of time to determine both that they are eventually accepted and influential. Some physics nobels have been awarded for things done decades ago. I can't think of one given for something that was done the prior year - maybe you could give an example.

Schmidt and Reiss should be in the running for it some year, though this one may be too soon.

I wish I had posted the first time I believed this. I suppose a lot of people knew it would come eventually, though.

On your recomendation Martin I ordered The Trouble With Physics yesterday from Amazon.com. I also picked up Not Even Wrong, partly on impulse. Looking forward to reading them.

It may take me a bit to get into them though. I'll do my best.

By the way, not long ago I finished the book True Genius, The Life and Times of John Bardeen. It was amazing. Just a thought for the future

My copy of TwP arrived! I have read much of the book.

Well how about an update!

I would like your opinion on whether I would find this book interesting. I have not thought much of string theory since I looked into it in 2001. Since I don't need any convincing, would the book contain enough new information that I would enjoy it?

Thanks in advance

String theory has not been pursued in any "odder" fashion than other theories in physics. Dirac used to write pretty equations and even went so far as to say that the accuracy of the theory should be judged by the beauty of the equations.

I would agree with Luke that ST is certainly being pursued in a historically unusual fashion. Dirac may have liked pretty equations, but his contribution to physics was very much dependant on experimentation that had been done. Quantum mechanics was a science born of experimental data that conflicted with current theories. There is no such example for string theory.

General relativity might be one good example of a broad theory being produced before experimental data (of course special relativity would not be). Of course it rested on a single, powerful principle, something that can't be said of string theory, but I agree with you that this demonstrates such a sequence is possible.

This still leaves string theory in a historically unusual position. There is no expeirmental data that demands a theory of quantum gravity. There isn't even absolute evidence that such a regime where a theory of quantum gravity is needed even exists, and if it does, it is difficult to imagine a situation in which the theory would be useful.

Of course most physicists would prefer to sit around playing with pretty equations, but let's not forget this urge can work both ways. When Pauli started working on the physics of solids he quickly stopped and warned his students against studying the "physics of dirt." I wonder what those students thought when Bardeen later went on to earn two Nobel prizes studying just such physics.

You just said that the predictions were wrong. They didn't go away. So ST is still making predictions now[/i']... We still have vibrating strings/'branes, right?

I'm not sure I agree with this. The theory is significantly different than it was in the mid-80's, there are those who say it is no longer really a theory of strings, and the predictions of the past did seem to be swept under the rug as time went by. Of course, I guess its a fair question as to whether the word "prediciton" ever applied to anything that came out of the field. Maybe "suggested" is more appropriate?

Just relax.

Theorists in particle physics have about thirty years of doing a superbly awful job predicting anything anyone measures before it's measured. This problem has seemed to get worse, not better. Whether or not what the LHC is doing is dangerous (certainly not), the fact that some guy somewhere predicted something bad might happen can be ignored, since there is no good reason to think he's anywhere within the realm of reality.

If Laughlin were proved right, I think it would be not because warmish superconductors are inherently too complex, but because we are NOT A GOOD ENOUGH ANIMAL. I reject that repugnant idea in every fiber. I think Laughlin is old, and old guys, if they havent already done something, get to thinking it is beyond human capacity.

Well it should definitely be said here that while Laughlin has contributed a great deal to physics, many of his current views are... unorthodox, at the least. Certainly many other experts in the field disagree with him on that.

The problem with HTS may be more than a problem of not having the appropriate mathematics available though. It may be that what we group under one name is actually a huge set of highly variable separate effects many of which are independant of microscopic factors of the system and shielded by quantum protectorates. In such a case we have to ask ourselves whether there is the possibility nature gave us a knot we can't untangle; we may be able to form some predictive ideas, but they won't be generalizable and won't give us any good picture of the underlying physical mechanisms.

You are certainly right to say this is pure speculation. It seems, based on history, a poor bet to make that we will uncover a problem we can't solve. And yet, we may have already done so in the past and are just used to the idea. Turbulent fluids comes to mind.

This, to me, would be The problem with physics - the identification of a broad problem rooted in experiment we can't solve. In other words, a physical system we can't appropriately describe. To me, quantum gravity doesn't actually meet this criteria as of yet. I think there is another book in all this.

But deciding the statements are wrong because the reviewer is abusive, insulting, obnoxious, etc, is not valid.

I didn't say anything about deciding they were wrong. Please read my post more carefully.

2. It is untrue that String Theory has not made a single prediction.

This is correct. String theory has made a few vague' date=' general, but useful predictions in the past. The point is they were [i']wrong[/i]. The discovery of a cosmological constant was a huge blow to the field.

String theory certainly doesn't make any predictions now in the form(s) that it is. Its continuing failure to reproduce the standard model decades after inception suggests that it suffers from a very serious problem indeed.

Locrian, The math in string theory is incredibly complex by most standards, and so unless you are involved in the theory or have studied it through a textbook or something similar the mathmatical arguments wouldn't make much sense.

True, but the physical ones certainly can, which means it is still an interesting subject. As for the Feynman quote, I've heard it too, but as much as I still agree with it, the truth is it was said decades ago and string theory is really an entirely different animal now.

1. Writing a wrong paper gets you a lot of credit since people will write papers saying it is wrong, giving you citations.

This is a great point. Also, to me it seems like this algorithm penalizes people responsible enough to cite lots of other people's ideas. But as Martin says, it is just for fun (let's hope).

If anyone else has any opinion about whether Anderson is actually a good choice for "most creative" I'd be interested in hearing it.

Hi Locrian and others following this thread' date='

 

It's quite understandable to be irritated with the book title saying

"THE trouble with physics".

 

it sacrifices precision and appropriateness in order to avoid wordiness and to be catchy enough to sell books.

 

titles are often a compromise---either between author and publisher or between different concerns the author has in mind.[/quote']

 

It is certainly true that the author of a book should be given a bit of room for dramatic flair with their title. Maybe I am being too sensitive about this one, but I have to admit to being tired of all of physics being represented by one or two areas.

 

I have been trying to think of what kind of thing could be considered a real, serious problem for the future of the discipline of physics. The only thing I can think of is if it turned out that there was a growing list of experimental data which could not be given a good predictive mathematical and physical theory.

 

For instance, what if, fifty years from now, our understanding of high temperature superconductivity was not improved? Laughlin seems to think there is a chance we will never have a reasonable predictive theory for it. What if there were also two dozen other physical processes we understood just as little? What if we could demonstrate that because of some property of the system, a predictive theory could not be produced for those? That, to me, would be a philosophical problem for the discipline.

 

I wonder if you think such a thing could even happen, Martin?

Being contradicted by the data. That's the ONLY reason to discount an opinion within science.

Right, because book reviews can be judged based on wether they contradict the data or not.

Can anyone who has read or has a familiarity with the book sum up exactly what The problem with physics is supposed to be, as made in the book?

Yea it was my understanding that Severian was reffering to Motl, and that was the subject of my post. Motl was not asked the 2006 edge question.

Actually I would like to retract with apology any reference made earlier to that contentious personage, the important thing is not to let discussion shift to being about personalities. I regret any mention of such as might become the focus of discussion and thereby supplant productive exchange of ideas.

Fair enough, I'll not add to that discussion even if it reappears.

More on topic, the thing that annoys me about the book is its title: it should be titled A Trouble in Physics. I'm not aware of any problem that would qualify as being a problem in physics that affected every area of the discipline, and certainly none that have anything to do with HEP. I haven't read the book (and hope not to have to), but the title sure seems to give a very wrong impression.

Come on - the guy is a respected physicist. You may disagree with him, but to completely discount his opinion, and urge others to ignore him, is a bit much.

Well, I've never met anyone who actually respected him; I doubt anyone I work around knows anything about him. I'm sure they're out there, but calling him "respected" deserves some sort of context. On the other hand, Motl has a habit of being abusive, insulting, irrational and absurd. I can provide any number of quotes from him made online that consist of nothing more than personal insults with no information, no argument and no intellectual value.

Discounting his opinion... hard to say... but if being obnoxious, unprofessional, unproductive and childish isn't reason to ignore someone, what is?

I have a question Martin - its one that occurs to me every time I see the title of this book.

Does the book actually pose problems for Physics, or does it merely pose problems for some specific area of physics he happens to work in?

Because it seems to me that areas like organic electronics, high temperature superconductivity, nanotechnology, lasing, and even cosmology and astrophysics in general, are all areas that continue to do interesting experiments, propose interesting problems and produce interesting theory. Do you know if he actually adresses that?

so it is definitely an important step forward! M33(triangulum) and M31(andromeda) are quite a lot farther away than LMC' date=' and they are much bigger and have more Cepheids.

 

So it would be a big improvement if people could get the range on a dozen or so DEBs in places like M33 and M31.[/quote']

 

You are absolutely right! Having a second anchor galaxy would be an achievement. This is clearly stated in the paper, which I just finished reading. I still have that bad feeling in my stomach, due to the sample size. I hope it takes them less than ten years to add more observations to it.

Apoligies if I'm going to sound like an Eeyore here, but I think the author of this article does not have things in perspective.

1) 16 billion and 14 billion are pretty close. It was only a decade ago that estimates ranged form 8 billion to 20+ billion.

2) Their method of determining Hubble's constant has some room for error. They determine the masses exactly, but deducing the absolute value of the brightness based on the mass is not exact.

3) The scientists, as far as I can tell, have a sample size of one.

I really think the journalist involved here didn't look critically enough at the information they were given. It does not seem to be newsworthy to me at this time.

Thanks for posting it anyways though.

I don't know the answer. I am therefore no use.

Here is something I will try tomorrow though: when an object is around z=1.5 redshift, what will its angular size be, and how does this compare to the frequency of light we would be observing?

I notice that both your articles have to do with radio waves, which will have a much, much larger wavelength than optical ones. Maybe that makes it more pronounced.

There. I made a guess. Tomorrow (or sooner) I will find out if it has any merit.

I thought CPL.Luke provided a good enough reason of why it 'appears' to be travelling faster. On a side note, I think that article is meant to mislead (for amazement factor).

And, for the record, I will concede that if you twist yourself into knots and ignore the need to actually be able to predict what is going on in these systems efficiently, you can write off all of these interesting effects in such ways.

However, it isn't useful, or even particularly logical. In materials with a positive index of refraction, varying phase and group velocities are trivial to write off. In anomolous dispersive materials, it requires more acrobatics, and begins to look very strange. In left handed materials, the explanations just sound absurd, and lead to terribly illogical conclusions.

Such as the paper I cite above. I can post a couple more if anyone finds that of value.

Could you send me the paper please?

How would you like it?

If you have access, here is the reference:

Valanju et. al.,Phys Rev Lett, 88, p 187401. "Wave Refraction in Negative Index Media: Always positive and Very Inhomogenous.”

Some choice quotes:

We show that ng is positive in NIM, and hence all interpretations of phase refraction as “negative light refraction” and “light focusing by plane slabs” [1 –6] are incorrect. Further, we argue that, in general, causality and finite signal speed would be violated if any physically realizable wave (signal) suffered “negative refraction.”

In conclusion, we have shown that causality and finite signal speed preclude negative refraction for any waves incident on any material, including NIM. The NIM dispersion implies positive group refraction even when phase refraction is negative, and causes large angles upg between phase and signal fronts and creates inhomogeneous waves that rapidly decay, during and after passage through NIM. The strong distortion of the signal puts severe bounds on the bandwidth of the information that can be transmitted through NIM devices. Negative refraction ray diagrams in all earlier literature do not represent the correct positive wave (i.e., signal) refraction by NIM.

Experimental confirmation of the things they claim to have proven impossible in the paper came about... well, about the same time the paper did.

CPL.Luke is right, the position of the peak changed making it appear like it was faster than light velocity.

Right. With the small exception that the statement is physically inaccurate and logically inconsistent. A more correct response would have taken into account that the cesium trap and NI materials mentioned in the article have refractive indices that depend on frequency, and therefore the measurement of the group velocity isn't an acceptable measure of the speed the light is traveling.

Saying something "appears" or "looks" to be traveling faster than light is ineffectual without giving a good reason for why it does.