Planck Definition and 393 Threads

So whose quantum gravity theory will crash-and-burn if this is correct? http://physicsworld.com/cws/article/news/40834 Zz.

I am interested if you know somebody who did research, a theory beyond the Planck length, equal to 1.616252(81)×10−35 meters; between 0 meters and Planck length. Are some Big Bang theories...

"The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the ‘quantum of length’, the smallest measurement of length with any meaning." What I am wondering about this description is the word "dominate"...

It seems like if you accelerated a massive particle to a high enough velocity (momentum), you could get it's wavelength to be less than the Planck Length. Does that make sense? As always, thanks in advance.

These questions are rather like the one mahela007 just asked, but are perhaps a little more specific. I have never clearly understood how the Planck hypothesis (E=nhf for the oscillators of a black body) fits into the later quantum theory of Schrodinger, Heisenberg, et al. Specifically...

If a string has a Planck length then why doesn't it have a huge Planck mass? Perhaps it does but its negative gravitational self-energy counteracts this huge positive mass/energy. Maybe a closed string can be thought of as a Planck energy electromagnetic wave trapped by its own...

The Planck team have put out a press release their (very preliminary) results for the First Light Survey: http://www.esa.int/SPECIALS/Planck/SEM5CMFWNZF_0.html The basic gist: the instrument is working, and it's already producing higher-resolution and lower-noise maps than WMAP offers at the...

hi everyone, one of my homework questions asks me to write a computer program to evaluate the Planck distribution at any temperature and wavelength and add it to a routine for evaluating integrals for the energy density of the radiation between two wavelengths. I have never used any programming...

http://img233.imageshack.us/img233/5816/espaotempoquntico1.th.jpg Two pictures of quantum spacetimes... The theory of quantum gravity (LQG) can perform calculations and predictions on the concrete structure of space and time at the Planck scale. Equations formulas that describe...

In his book THE BLACK HOLE WAR, 2008, Leonard Susskind makes the following comments around page 135-137: In the following he happens to be referring to a Planck scale cube...let's ignore that specific geometric shape... (Later in the book of course he describes his holographic...

Are Planck units the same in all frames of reference ? If so, shouldn't the theory of relativity be modified to account for this ? (same as considering the speed of light the same in all reference frames) Because in it's current form, for a large enough velocity, through length contraction we...

I was always puzzled by the fact that while almost all Planck units are extreme (very high or very low), Mass and Energy are exception from that rule. Planck mass is in the ‘middle’ of the spectrum, and it divides the mass spectrum into 2 parts: For small masses/energies m << Mplanck we can...

Can we synchronize n samplers so that the system is being sampled at 1/n Planck time? What could we tell about the data values between two adjacent samples?

Almost: the result is 85 GeV, the measured mass is 80.4 GeV. Is there anybody who has ever looked at this coincidence? François

http://www.ift.uni.wroc.pl/~planckscale/movie/ The first one I intend to watch is Steve Carlip's He is talking about similarities that have emerged among different approaches to QG. In particular evidence for reduction of dimensionality as you zoom in (inspect the spacetime geometry at smaller...

There seems to be a difference in the way relativity views Planck length as frame dependent and the cosmological constant, an energy density?, as invariant...Any insights appreciated! There is a well known contradiction between relativity and the Planck length: Wikipedia explains the...

Jose Figueroa is in the Math Physics group at Edinburgh and his research centers on string and susy: http://www.maths.ed.ac.uk/~jmf/ There was a big conference in Poland just now (ending today 3 July) which was interesting partly because it was mixed. Stringers gave talks alongside nonstring...

At low energy, the value is around 1/137.036. What is the value at the Planck energy? Is it listed somewhere? After all, the renormalization of the charge (as it is also called) is mentioned everywhere. But numbers are rare ... Hz

If this is in the wrong section, I apologise, and would appreciate it if a forum veteran would show me the wrongs of my ways. Homework Statement In one of Zeno's paradoxes, it is argued that travel over any finite distance is impossible, because the distance can be divided an infinite...

Homework Statement I can't find the proof of "the ratio of the number of oscillators in their (n+1) )th quantum state of excitation to the number in nth quantum state is: k is boltzman costant N_(n+1)/N_(n)=exp(-hω/2π(kT)" Homework Equations The Attempt at a Solution:-( I don't have any idea

The topic was taken from Chapter 5 in Prof. Susskind's book, The Black Hole War. Prof. Susskind pointed out that once Planck converted the unit such as length, time and mass from the Metric Standard to Planck Standard that allow the Universal constants which are light's speed (c), Gravitational...

Has an entity in the universe ever existed with a charge magnitude of 1.87755e-18 C (planck charge)? When/where could it arise?

does anyone know something about the ratio of Planck length to Planck mass : signification, use in quantum relationships...

Homework Statement a. The first part of this problem was to derive the escape speed (Vesc) for a star of mass M and radius R. b. The second part is where I am having trouble. It says to equate the Vesc calculated above and derive a formula for Planck length in terms of c, G, and h_bar...

Why we are searching quantum gravity effect at the Planck scale? The question seems very stupid (and may be) but let me explain. I define a quantum object when his action is of the order of Planck constant \bar h. namely A~E \delta t~\bar h. So if i take a small amount of energy E i can take...

Hi everybody, it's my first post on here but as i seem to have hit a brick wall with my work I'm hoping somebody might be able to help me :) Homework Statement I'm looking at how the Planck scale is reduced in higher dimensions (ADD theories) and I've managed to reproduce an expression...

I found a facsimile of the original article where Planck gives a value for h (except that in May 1899 he was calling it b, instead of h.) http://bibliothek.bbaw.de/bibliothek-digital/digitalequellen/schriften/anzeige/index_html?band=10-sitz/1899-1&seite:int=454 Here is the exact page where...

In my new found passion to understand the "inner meaning" of this thing called quantum theory, I've been trying to find Planck's derivation of -- or explanation for choosing -- the "constant of nature" that has become so popular. I expected to be able to find the empirical basis for it very...

How do Planck's photon theories relate to the belief that all forces may be unified at high speeds? I understand that light waves can act as particles, and particles can act as light waves. Waves/particles emit energy. And Planck's scale is believed to be around the length of convergence of...

Hi all, in a couple of books I read that Planck's original derivation of the blackbody radiation had some problem related to the zero point energy, which was solved after quite a few years (when Schroedinger formulated his equation). I sort of see this problem, but I'm not sure the...

Hey folks, I just had a thought I wanted to share with you guys. Just to review first the idea of Large extra dims before I make the comment: The higher dimensional Einstein-Hilbert action is given by S_{bulk}=-\frac{1}{2}\int d^{4+n}x\sqrt{g^{4+n}}\tilde{M}^{n+2}\tilde{R} where...

A section in my textbook talks about Planck time, but I still don't quite get what does it mean after I finished reading it. I am also wondering whcih laws of physics can be applied to the Planck time. Some info that might be helpful for answering this question: tp=√(Gh/c^5) where G is the...

What happens to the Planck length due to the expansion? Does it grow with the scale factor?

So I have a question on the Planckian (from one of my PhD qualifier practice problems). I'm trying to derive the Planck distribution from the Bose-Einstein distribution, which is, f(\epsilon) = \dfrac{1}{e^{\frac{\epsilon - \mu}{k_B T}} - 1} Now I know that I can set the chemical...

According to my research on the Standard Model, gravitation is mediated by a massless graviton with spin 2. Upon examining the unity of comparison between cosmic time and quantum unification listed in reference 1, the unification of two forces is scaled at the rest mass (energy) of their bosons...

All the below is presented in latex format. In Schroeder's intro to thermal, problem 7.38, he asks you to substitute \lambda = \frac{hc}{\epsilon} into the following equation \frac{U}{V} = \int^{\infty}_{0} \frac{8 \pi \epsilon^{3}/(hc)^{3}}{e^{\epsilon / kT}-1} d \epsilon...

Many arxiv papers state that the Planck length is the smallest measureable length. On the other hand, the gravitational length L=2Gm/c^2 associated with every electron or proton is 19 or 22 orders of magnitude smaller than the Planck length. Nobody seems to doubt either of the two statements...

I'm working on a project that requires me to numerically integrate the Planck spectral distribution. The object is to find the median wavelength, with exactly 50% of the radiance on either side. I'm using a standard composite Simpson rule method and I get good convergence with temps around...

for hv>>kT how does exp(hv/kT) compare to 1? I understand hv >>KT leads to an exponential fall in brightness but why did Planck introduce 1 in his equation. and only for values hv<<kT can this exponential be expanded! Thanks for any help!

If the Planck constant tends to zero, it's obviously just getting smaller, so how would this describe classical physics? Is this a way of explaining it?: If energy spacing E = hv, and h --> 0, then E --> 0, which is essentially a continuous energy spectrum and quantization and discreteness...

On a ruler, you could move from the 1cm marking on a ruler to the 2cm marking, or you could move from the 0.5cm marking to the 1.5cm marking - both are 1cm movements but you cannot go from 1.5cm to 1cm in a 1cm movement. If we had Planck co-ordinates, could you move from 1 => 2 and also 1.5 =>...

Homework Statement Deduce an approximation for Planck's radiation law: To what what wavelength does hv/kT=1 Homework Equations Wien Distribution equation B(lambda)= 2hc^2/lambda^5*exp(-hc/kT(lambda)) Rayleigh-jeans approximation B(lambda)=2ckT/lambda^4 The Attempt at a Solution My...

What happens with causality at the Planck scale? Can effects "precede" causes? I would like to know what happens with causality at the Planck scale, explained in "educated layman" terms, if that's possible... :) Might effects "precede" causes in time? Do we have to redefine causality at the...

Why are Planck quantities considered to be maximum and minimum quantities - Planck distance etc ? If they are,then,since in calculus a maximim/minimum is given by,for example,dy/dx = 0,then,for example,y = Planck quantity when x = some other quantity.But what is x?

How are the Planck length, Planck time, and Planck mass "derived"? I know their values, but I don't understand where we get them from.

Is the Planck time/length/mass affected by relativity, or are they constant (independent of relative velocity and/or gravitation field)? Same question for the Heisenberg Uncertainty Relation. Is it observer dependent?

In "Black Holes, Information and the String Theory Revolution" by Leonard Susskind and James Lindesay, the authors give, (Ch. 15: Entropy of Strings and Black Holes, pg. 170): "The string and Planck length scales are related by g^2* (l_s)^D-2 = (l_p)^D-2 (15.0.23) " They then find...

I was doing a thought experiment and came across something that I'm going to term the Planck Circle Problem for the sake of naming it something. The logic is as follows: 1.) All lengths contain an integer number of Planck Lengths. 2.) The radius and circumference of a circle are both...

As a result of my thread about local coordinates, frames distances, calculators etc. , I proceed now with this one about Planck blackbox radiation. I do this because I did not want to disturb other threads where I eventually could fit this in. Because it still has something to do with...