Modern and Theoretical Physics

So, the earth has its own electromagnetic field. Could it be possible to upload information into this field indefinitely?

I’m initiating this thread because I don’t think people appreciated that this was the key part of Wheeler’s remarks. One of the main themes of the first thread was the obvious point that energy is needed to physically encode information. We don’t really need to examine the concepts of time or interpretive issues having to do with quantum mechanics to understand why this statement makes sense. But the question of the relation between information and energy takes it’s sharpest form in the case of black hole physics. This is because of the famous black hole area-entropy relation which says that the entropy of the event horizon is completely determined by the mass of …

According to recent observations, yes: http://www.news.ucdavis.edu/search/news_detail.lasso?id=8364 Different frequencies of photons travel at different speeds? Speeds other than c?

We've reached the target date and there is no way short of divine intervention or a computer error that their prediction will not turn out right. I just checked Amazon.com and going by salesranks the Smolin book was selling over 9 times better than the five most popular string books average. Checking at noon pacific time will make it "official" but i don't see how the picture can change substantially in the next three hours. *The Trouble with Physics...and What Comes Next* rank was #637 among all books, and the top five stringies were fabric 4021 elegant 4542 endless 6633 warped 6710 parallel 7140 so the average stringy rank was #5809.2 and the ratio 58…

In another thread the issue came up of judging the scientific QUALITY of research. Department hiring and tenure committees do that in part by looking at the CITATION COUNTS of the papers somebody's written. Lots of cites mean that other researchers in the same field consider the work significant and relevant to their own line of inquiry. Like any numerical measure, cite-counts have their limitations---sometimes one's subjective feel can be a truer guide to the real quality. Be that as it may, the SPIRES system at Stanford-SLAC puts a lot of effort into keeping citation counts for everybody's papers in hep-theory and hep-phenomenology, as well as a bunch of other fiel…

Lee Smolin's latest book, The Trouble with Physics...and What Comes Next came out a year ago (September 2006) and initiated controversy. Has the controversy been good or bad for the physics profession, in your view? Has anything changed as a result of discussion? Will there be any effects, good or bad, on future directions of research? What's your view on this? Is the controversy over? If not, how is it going? One way to measure how it's going, on a sheer quantitative level, is to check the Smolin/string salesrank ratio using the physics bestseller list at amazon.com. What do you predict the Smolin/string ratio will be a month from now---say noon Pacific time on 1 O…

I'm looking for a diagram that shows the shapes of different orbitals along with what element they correspond to. I've found lots of pictures of orbitals online but very few that label the type of atom (element) they're associated with. Any links would be greatly appreciated.

I am curious if there is anyone on here that would under some circumstances could imagine a sensible fundamental non-unitarity model of physical reality? To argue about conservation of probability may seem foolish, because it follows from the axiomatics of probability theory. This is not the level the question is intended. The key is, in reality, as opposed to pure mathematics, can we really properly attach the axioms of probability theory to a fundamental theory? That we can do it with great success in many effective theories we all already know. So that isn't the question either. We can calculate the probability, and then collect all the data from the lifetime …

I have a question about the lepton mass mixing. We currently believe that the three generations of neutrinos mix with each other to produce three mass eigenstates, each of which is a linear (and orthonormal) combination of the weak interaction eigenstates of electron- muon- and tau- neutrinos. This mixing violates flavor symmetry. Such a mass matrix can be generated by Yukawa couplings of Higgs scalars to the leptons, which produce tree level mass terms for the leptons through their vacuum expectation values. The source of the non-diagonal mass matrix does not have to be based on Yukawa couplings, it may be something else altogether. The precise origin of the mass …

From the titular concept of Smolin's book (you know, the one everyone forgot about after TwP) there are three ways to approach the development of a quantum theory of gravity: 1. Start with general relativity and find ways to unite it with quantum mechanics (the loop quantum gravity approach) 2. Start with quantum mechanics and find ways to unite it with general relativity (the string theory approach) 3. Something completely different I was wondering what the opinions around here were on these approaches

Hi everybody, Let me be absolutely clear that by "strings physics only" I mean to not only exclude discussions of alternative theories, but also restrict discussion to technical and conceptual issues in string theory itself. If someone wants to discuss alternative theories in relation to discussions in this thread, they should initiate a new thread for that purpose. This thread is meant to help members (including myself!!!) deepen their understanding of string theory on it’s own merits and not in comparison to other ideas. To those members searching this statement for loopholes to exploit, I expect posters in this thread to also respect the spirit in which these remar…

This idea popped into my head while I was taking my nighly swim. It is a way to travel back into time, without violating any laws of physics, using only well established principles of physics. It ends with a twist. Picture this scenario, you share a large house with a group of closest friends, both male and female. One day you leave the house to get some adult refreshments and NASA scoops the house up and send it into space at near light speed. In their reference, say, only a day goes by, due to their relativistic velocity. But in your reference, say 20 years go by. After twenty years, NASA puts the house back. When you go to see your old friends, they have not …

I started this thread for general stringy questions, if anyone is interested. Discussion is carried over from http://www.scienceforums.net/forum/showthread.php?t=28281 Wormwood--- Good question. This is actually one of the great successes of string theory---the fact that it predicts a number of dimensions is a success that no other approach to quantum gravity can claim, yet. The dimensions are predicted from the theory, by the requirement that the theory be consistent with quantum mechanics. In order to quantize a theory consistently, we have to introduce an idea called gauge invariance. This basically says that physics cannot depend on the way tha…

http://download.iop.org/pw/PWSep07strings.pdf This is a pretty good article, and sumarizes the attitudes of the people in the field (at least that I know) pretty well.

In an article in "Popular Science" I read a theory of how light speed could be acheived and the article said something about a bubble of electrons that the vehicle stays in which keeps the space inside of it a normal while the vehicle compresses the space in front of it and expands the space behind it and apparently using this method it's possible to "travel time". Does anyone care to explain to me how this is even remotly possible? Now I most definitly am no quantum physics expert but I think all this is impossible though I know that space expands and whatnot I dont see how it can be controlled like that. The closest thing to this that I can think of is somehow slowing d…

Lagrangian density for a self interacting real scalar field in four space-time dimensions is: L = (1/2)* [((del-mu)fi) * ((del-mu)fi) - (m**2) * (fi**2)] + (1/4) * lambda * (fi**4), where fi=real scalar field, m=mass, lambda=quartic self coupling constant, and (del-mu)fi=derivative of the field fi with respect to the space-time index mu, with mu = 0,1,2,3. If lambda=0, we have a free scalar field. With lambda > 0, we can scale it away with a simple transform: psi = fi * sqrt(lambda). If we substitute psi for fi in L we get: L = (1/lambda) * { (1/2)*[((del-mu)psi) * ((del-mu)psi) - (m**2) * (psi**2)] + (1/4)*(psi**4) } Expressed for the new scaled field psi,…

I recently came up with an idea for a new type of particle accelerator that could potentially be twice as efficient as present accelerators are. Ordinary particle accelerators are circular and send two beams of particles in opposite directions around the accelerator and slam them into each other. I realized that there could potentially be a more efficient shape in which to build an accelerator than a circle; a figure eight, or at least something reminiscent of a figure eight. Even though a circle is the most efficient shape to accelerate particles in, a figure eight could be made to have two circles in them simply by drawing a half-circle on both sides of the intersec…

I think that I have proved that the Special Relativity Theory (SRT) is not correct. The proof is based on the fact that a clock (which is a highly deterministic Cesium 133 atomic clock) will not go through the clock re-phasing transformation which is required for SRT to be correct. The re-phasing is a derived requirement based on the condition that the speed of light "c" has the same value in all inertial frames of reference. I have a standing offer of $5k for the first person to show that I'm wrong about SRT. I'll send copies of my .ppt slides and published articles addressing the SRT problem to anyone who asks for them. Emaill me at: tmorton9@cox.net

I`m quite Fascinated by the idea of this, and since we don`t have a section for it, I figured Here would be the best place. Now, if we look at a decay chain of an isotope you`ll see many daughter products are "born" or decayed into. now from a Chemist standpoint each has their own particular Chemical properties, such as Valency (oxidation states). now supose along this decay chain with start with an Isotope Mono Oxide called XO, along it`s decay chain the Mono oxide cannot exist, it has to be YO2. now imagine there is No free oxygen available and it`s in a sealed environ evacuated. what happens? do you get half become YO2 and the other half as pure Y…

One question I rarely see discussed concerns the limits our brains impose on our ability to conceptualise "extreme" physical realities, (micro and macro). Particles as "points," or "strings," quanta as "packets" ... all these assume an analogy from the less extreme physical realms of dots, elastic bands and shopping trolleys. The possible limitations might arise within our own brains. Is there any research to suggest that there are indeed limitations on our brains' power to model complex structures and might machines do any better?

lets suppose that some one found that there was a negative mass particle then we could have space ships with no net mass. but how how do you accelerate an object with no mass? any ideas

One question I have about Superstrings is this: What, exactly, would one look like? Or more specifically, what would be considered as evidence that they actually exist? I've been searching in the books that I have, such as a Brief History of Time and Elegant Universe, and they never really talk in great detail about what would be considered as evidence of their physical existence. Its the same with multiple dimensions that they are supposed to exist in (both 11 and 26 dimensions) I would imagine that if we did actually find solid evidence, I'd imagine that we would measure effects associated with gravity, and it would probably crank out some exotic particles that we h…

Smolin "Trouble" has done well. I just checked as of Sunday 26 August noon Pacific time and it was the #4 amazon physics bestseller, with storewide salesrank 938. It is fairly unusual for physics books to get salesrank under 1000. It was selling better than the usual string favorites (Greene, Randall, ...) as you might expect, since it's #4. UPDATE: by 2PM the same day it was #3 physics bestseller with storewide salesrank 825. The orange paperback edition has replaced the blue hardcover that came out a year ago. "The Trouble with Physics...and What Comes Next" has actually been out almost exactly a year. The blue hardcover first edition officially went …

Europe has a European Science Foundation, like the NSF we have in the USA. And the ESF has set up two new funding agencies called "networks" recently. These are multi-country arrangements where 8 or so countries pool resources with one director and advisory board with a charter to support some specific kind of research. In each case there's a committment of some millions of dollars over some period of time like 5 years, from the participating countries, and then the network charter goes up for renewal. In the past 2 or 3 years there has been a big increase in research activity in nonstring QG (that covers several categories) and almost all of it is outside the USA. …

I'm quoting myself from this thread. The original question was what is an example of a particle that splits into two particles with opposite spin, and the answer, given by swansont, was that a J/psi particle will split into an electron and a positron with opposite spins. Then he added the above quote, which I found very interesting for the reason I mentioned. No one really took it from there, but I still find that interesting, so I'm starting a new thread on it. So... it seems like the J/psi particle, which is composed of a charm/anticharm quark pair, transforms into an electron and a positron. Now, if I'm not mistaken, an electron is a fundamental particle (as far as…