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Talk:Quantum mechanics/Archive 1

First discussion

 * Quantum mechanics has provoked a strong philosophical debate. The fundamental problem is that causality and determinism is lost: while the probability distributions evolve according to a well established deterministic law, the values of the observables themselves do not. Because of this, Albert Einstein held that quantum mechanics must be incomplete.

It would be helpful to try to give some basic explanation of why Einstein's view is widely held to be incorrect--his view seems like common sense, but common sense is often wrong, as theoretical physicists enjoy pointing out. So, why is it wrong, in this case? By the way, please don't answer this question on the /Talk page--please put the answer on the QM page. Thanks in advance! --LMS

It's not entirely clear that Einstein was wrong on all counts, just wrong on at least one of them. :-) The Bell's-inequality experiments of Aspect prove beyond any doubt that either (1) Observable effects exist that cannot be deterministic results of inherent properties of matter; or (2) The universe is non-local; i.e., physical effects can propogate faster than light. Nobody knows which.  --LDC

It proves neither, since neither is the case in the multi-universe interpretation. --JG

I'll put a discussion of these issues on the Copenhagen interpretation page. --AxelBoldt

In the "Description of the theory" section, it states that the view of the electron circling a protron was replaced by the view of a static "probability cloud". However, this gives the misleading interpretation of the electron as being "smeared" in some distribution around the proton, which isn't really case. The electron does in fact move around the proton, we are just unable to predict the nature of this movement and can only predict the probability of finding the electron in any given location.

That the electron is not "smeared" throughout the distribution, but occupies unique points in space is evidenced by the relative inaccuracy of the Hartree-Fock approximation compared to Density Functional Theory or other methods that attempt to account for the "correlation energy" that arises due to the interactions between moving electrons. --Matt Stoker

Current understanding is that the electron is smeared. If a wave function was just a probability distribution for a particle that actually had a given position, the double-slit experiment wouldn't work, since the electron would have to travel through one slit or the other. I'll admit to not knowing precisely how correlation energy works, but absolutely none of the fundamental quantum mechanics I have seen treats orbitals as anything other than stationary states. --Josh Grosse

The electron cannot be smeared over the orbitial, since if it were then the electric field would also be smeared. This smeared view of the electric field is the limiting assumption in the Hartree-Fock approximation and is the reason for it's limited applicability to multi-electron systems. The electric field cannot be treated in an average or smeared fashion because electrons repulse each other, this repulsion results in an instantaneous distortion of the probability distribution for a given electron that depends on the instantaneous position of the other electrons at any given point in time. The difference between the exact energy and the Hartree-Fock energy due to these instantaneous electron interactions is called the "correlation energy".

My understanding is that modifications of the double-slit experiment were performed in which the researchers attempted to detect which slit the electron passed through. In these experiments, they were able to determine which slit each electron passed through, but the measurements perturbed the system, such that the typical diffraction patern did not occur. In other words, when the electron was detected as a particle with a definite position, the system behaved as if the electron were a particle. The wave function collapsed, because the electron position was detected. I would imagine that the interactions between electrons are similar. Instantaneous interactions between electrons cause the wave functions to collapse, so at any given time the electrons "see" the other electrons with a unique position and the electric field corresponds to specific electron positions. --Matt Stoker

But electrons are always interacting with other electrons, so if this was enough to collapse the wave function, you could never have an electron in two places at once. What happens when two electrons interact is that their wave functions become entangled, and that's where the correlation comes from, although I don't know the mathematical details. In the copenhagen interpretation, you need a real observer to cause collapse, while in the many-worlds interpretation, collapse does not occur at all (only entanglement between the system and observer). --JG

When I wrote the sentence about static electron probability clouds, I did not have "smeared out electrons" in mind; rather, I thought about a probability distribution that tells you how likely it is to find the electron at a given point, the electron being a particle, not a cloud. Maybe I should clarify that somehow? Any suggestions?

Also, we have some treatment of the double-slit experiment in Wave-Particle duality. Let me know if that is inaccurate. --AxelBoldt

Request to leave the sentence alone. In copenhagen electrons are clouds until observed - that's what wave-particle duality is all about - and in other interpretations they are clouds period.

Actually there's no conflict between having an electron "smeared out" and it having a velocity (~momentum). Since the electron is described by a wave(function) it can (and will) do both at the same time. The prime example here is a free electron. If a free electron has an exactly determined momentum its wavefunction will be spread out evenly over whole space (maybe a rather theoretical example..). Actually the electrons around a nucleus also both have a momentum and are delocalized (and you can solve the Shrödinger equation for Hydrogen exactly). Even if you go from Hartree-Fock to Full CI (Which is a method to solve the Schrödinger equation exactly within a finite basis-set) you still get delocalized electrons. -- Ulf Ekström

Axelbolt: the electron "probability" clouds are not actual abstract probability in respect to determining where an "electron particle" is, but rather a physical reality as shown by the double slit experiment. The method of observation determines the outcome. Which also brings me to another point, why is not more serious attention given to that besides a description of the multi-worlds theory? Can you say, bias? --Brendan Stork

Having reviewed more of the literature on this topic, I concede that I was incorrect, so I'm removing the discussion regarding electron clouds and acknowledging that the current description in the article is correct -- Matt Stoker
 * Note: I moved it back from Talk:Quantum Mechanics. It would have been hard to find otherwise, and needs to be part of the historical record. Graham 87 02:39, 29 March 2010 (UTC)

Perhaps some mention of the problem that inspired Planck to invent Quantum Mechanics is in order. IIRC, physicists were trying to figure out what electromagnetic waves were in an oven that had a certain amount of heat in it. They knew that an integer multiple of the wavelength of the light in the oven would have to equal one of the dimensions of the oven, but every time they tried to figure it out, they ended up concluding that the oven had infinite energy in it. Planck was able to find the answer by assume that the energy in an electromagnetic wave was quantised such that E ∝ f. This went directly counter to the classical mechanics assumtion that E ∝ Amplitude.
 * not quite, in classical mechanics it's proportional to both the square of the amplitude and the square of the frequency 63.205.40.243 05:12, 8 Jan 2004 (UTC)

I would like to request that we start an article "Mathematical content of quantum mechanics" and move most of the math material that is right now in the main article there. Two reasons:
 * 1) This article was meant as a general introduction, accessible without a deep understanding of the math or specifically devised notations like bra-ket.
 * 2) The math treatment right now is incomplete (it doesn't mention that the operators don't have to be defined everywhere, it doesn't mention which operators belong to which observables, it doesn't mention the possibility that an operator may not have eigenvalues, it doesn't mention the importance of the spectral theorem in dealing with operators that don't have a point spectrum.

Correcting the problems in 2 would compound problem 1.

--AxelBoldt

Good idea. How much of the current material do you think should be left in the article, and how much moved to the new page? The old section on "Mathematical Formulism" I found very difficult to read, which was why I expanded it. -- CYD

I can write a very simple version, basically saying that states are elements of Hilbert spaces, observables are operators, and the states evolve according to the Schrodinger equation, and then link to the math article. --AxelBoldt

I've correct some mistakes here,

1. ``three things that QM explains'' was misleading. Quantum mechanics explains (literally) thousands of things classical theory cannot. I changed the wording to reflect this.

2. There are classical systems where vairables can only take on discrete values (vibrational modes for example) so I took that part out

 * Those are all wave's however, whats new is that particles are waves too, and thus this happens for particles; Pretty much all of quantum mechanics predictions occur in classical wave mechanics 63.205.40.243 05:12, 8 Jan 2004 (UTC)

 * I put it back in, since arguably the explanation of energy quanta is the major achievement of QM and gave it its name. The fact that classical theory can explain some quantizations doesn't take away from the fact that most quantizations are explained only by QM. --AxelBoldt

 * It's not a matter of ``most''. The point is that quantum theory explains the right quantizations (energy levels in atoms for example).  But the wording seems better now. --Matthew Nobes

3. The idea that quantum mechanics ``omits'' quantum field theory is a bit strong. I changed the wording of that paragraph to more accurately reflect things.

4. The history of quantum field theory was off. I corrected the QCD part and added about about the electroweak force.

5. To the primary author, why such an emphasis on the many-worlds interpretation? It's really not widely accepted...

 * I hear that Hawkings and with him all cosmologists believe in it (since you can't really talk about a measurement apparatus separate from the system if your system is the whole universe) and Feynman also seems to have been a many-worlder. --AxelBoldt

 * Just because he wrote a pop-sci book does not mean that Hawking speaks for most physicists (or cosmologists). My main point is that there is no particular reason to emphasize many-worlds over (say) Bohmian mechanics. -- Matthew

6. Also, the quotes section seems really silly to me. It gives the impression that QM is somehow wrong, misguided and/or incompherensible. It is none of these things. I would strongly encourge dropping it.

 * Well, if you are not worried by QM, maybe you don't really understand it... :-) Isn't it remarkable that almost all the major researchers in the field expressed their unease in some way? Why should we suppress these sentiments? Instead, maybe we should add some positive quotes. --AxelBoldt

 * Umm did you add the new quote? If so you made my point about ``big names'' versus people who nobody has ever heard of. --Matthew

 * Rest assured I understand QM just fine :) If read in context the writings of the founders of QM often appear less negative, further by including quotes from before the 1980's you throw out all of the interpretive work that has been done since. Things have been improved by leaps and bounds.  Of course problems still remain.  A quotes section cannot do justice this vast amount of work.  As for positive quotes that doesn't really work becuase the average reader would assume that the Einstein quote is somehow ``better'' then the (say) Mermin quote on the basis of name recognition, despite the fact the the latter physicist understands *modern* quantum physics. In the end do what you wish, I'm only giving my perspective as a practicing physicist. --Matthew

 * Could you add some information to the Philosophy part of the article (or maybe create a new Philosophy of quantum mechanics) about the newest improvements in interpretating the theory? Is Copenhagen not the state of the art anymore?

 * Umm the philosophy/interpretation of QM is really not my field, so I'd be extremely reluctent to write anything about it. Ideas like dechoerence play a large role.  It would also be importent to stress the crucial role experiments are now playing in resolving some of the mysteries. --Matthew

 * Also, what I never understood and maybe you could clear up on mathematical formulation of quantum mechanics: does the theory give a general (hopefully axiomatic) rule about which operator belongs to which observable and which unit vector belongs to which state of the system? In other words, if you encounter a completely new "black box" system with a couple of observables, which Hilbert space and which operators do you use? --AxelBoldt

 * This seems like two (or more) separate questions. The first is asking how one assigns the various operators to the observable.  This is typically done with symmetry areguements a la Wigner.  There is a different (practical) problem of mesurments on an unknown state.  This is done by applying known measurement tools to the unknown state (i.e. a Stern Gerlach device) --Matthew

 * I guess the Wigner arguments are the ones I'm looking for. What would be a good reference? --AxelBoldt

 * Try a graduate level QM textbook. They all treat this stuff, with more or less detail.  I learned it from the very clear presentation in L. Ballentine's ``Quantum Mechnics: A Modern Development''.  Sakurai or Merzbacher might also be good places to look.  There's a new book out by Schwinger (posthumously published, entitled Quantum Mechanics) which looks like it treats things very clearly, but I've not had a chance to go through it.  Also, the first volume of Wienberg's QFT textbook has a very clear and concise discussion, except he uses the Poincare group instead of the Gallian group.  If you can understand his discussion then the application to non relativistic systems will be clear. --Matthew

I'm not the primary author, but I don't see any special emphasis on the many-worlds interpretation in the article. Could you elaborate?

Also, I believe the many-worlds interpretation has become more widely accepted amongst physicists than the Copenhagen interpretation, especially given the work in the past couple of decades on decoherence. Correct me if I'm wrong, though.

The quotes section is silly, I agree.

The philosophy section is currently rather poor. I ripped out a long description of the Cophenagen interpretation and the many-world interpretation, because those points are duplicated in the respective dedicated articles, and don't explain the philosophical issues. It needs to explain why Einstein felt that a probabilistic theory sucks, the philosophical problems with Copenhagen, etc.

-- CYD

I took out the following passage:

Quantum mechanics consists of 3 basic principles:
 * 1) All matter and energy is quantized. In other words, everthing comes in packets, or bundles. Therefore, one cannot have any amount of material. Instead, one must have a multiple of the smallest unit.
 * 2) All matter and energy exhibit has wave-particle duality. Matter and energy exhibit the properties of waves in some instances, and the properties of particles in others, depending on the experiment set up to observe it.
 * 3) Measurements of physical quantities are probabilistic. This is Heisenberg's Uncertainty Principle, which states that the position and velocity of a particle is not absolutely fixed at any given instant and can only be described in a range of probablities. Furthermore, any object does not have a definite position or velocity until it is measured.

I believe these are very misleading comments, and do not add anything to the article, but I'm willing to discuss it.

In (1), it is unclear what it means for "matter" or "material" to be quantized; less sloppy language is required. Furthermore, many quantum mechanical observables have continuous, not discrete spectra.

(2) had been mentioned earlier in the article, and Wave-Particle duality had already been linked to.

(3) had already been mentioned in the preceding paragraphs, and is much less clear than the prior explanations. Furthermore, it is momentum that is the conjugate observable to position, not velocity. Furthermore, the Heisenberg uncertainty principle works for observable pairs other than position and momentum.

I have not seen these three "principles" in any quantum mechanics textbooks. The postulates of quantum mechanics are described in the article mathematical formulation of quantum mechanics, which admittedly still needs work.

-- CYD

I agree, the first one is simply wrong, and the other two are already covered. And I also agree that we have to start getting serious about the math. forumulation :-) --AxelBoldt

Can AxelBoldt please justify his recent removal of the statement that QM explains and quantifies the particle nature of light? It seems to me that the particle nature of light is inherent in the definition of the wavefunction - one could dismiss it as a mere "postulate", but the same argument could be applied to the wave nature of matter. AFAIK the relationship between photon energy and frequency is derivable - say from the quantisation of angular momentum.

Actually, in my opinion that whole first section could be replaced by a description of the empirical observations leading to QM (currently relegated to the first paragraph of the "history" section). It seems strange to me to introduce QM with a randomly selected handful of theoretical results. -- Tim Starling

Quantum mechanics doesn't talk about light; Quantum electrodynamics does that. Quantum mechanics is strictly about masses moving around. A photon is a quantum of the electromagnetic field, so you need quantum field theory. AxelBoldt 01:59 Nov 11, 2002 (UTC)

 * That's all very well, but it leaves us with nowhere to discuss the historical development of QM in a balanced way. Planck's and Einstein's work involving light came well before QED was developed. Perhaps this page should be moved to Quantum physics (which I note is just a redirect to this page at the moment) - that way we can talk about the early development of quantum theory without guilt or confusion. We would also have a place to talk about popular thought experiments such as the single photon double slit interference pattern. -- Tim

 * Planck's and Einstein's work is mentioned in the History section without guilt or confusion: it preceded and lead to QM, so it belongs there. It is not part of QM however. The particle wave duality page discusses the double slit experiment. AxelBoldt

 * Okay, I give up. I guess I'm just used to the historical development being used as an intro.

 * Afterthought: you say QM doesn't talk about light, but what would you call the theory of atomic radiation based on time-dependent perturbation theory and classical electrodynamics?

 * I don't know what that is. AxelBoldt 04:14 Nov 11, 2002 (UTC)

 * Easily fixed - -- Tim Starling

The particle nature of light goes back to Einstein's explanation of the photoelectric effect, which is one of the foundations of quantum mechanics and obviously predates quantum field theory. Quantum mechanics doesn't necessarily deal with masses; you're thinking about the Schrodinger equation for a massive particle. For example, the quantum mechanics of spins doesn't talk about masses. -- CYD

 * Yes, I think Axel would argue that "quantum mechanics" is different to "quantum physics" - "mechanics" referring only nuts and bolts and the like. After four years of studying the subject, this distinction is new to me, and it sounds like it's new to you too. Obviously mathematicians are better at nitpicking than mere physicists. Nitpicking aside, there's a certainly common usage of the term QM which encompasses QED and the other "extensions". We have to ask ourselves - do we want to use Axel's definition, or everyone else's definition, in this encyclopedia? -- Tim Starling

Well, if you guys agree that QED is a part of QM rather than an extension of QM, then this article definitely needs to be changed. What is the proper name for the theory "observables are self-adjoint operators"? AxelBoldt

 * I wasn't sure, so I emailled God. Okay, maybe it wasn't God, just a professor of theoretical physics from my university. Anyway, here's what he said:

 * ''Yes, I would say that by common usage "quantum mechanics" usually
 * refers to the (nonrelativistic) quantum mechanics described by the
 * Schroedinger equation, while the full relativistic theory involving
 * "second quantization" is referred to as "quantum field theory". But then
 * an alternative usage of "quantum mechanics" would be to refer to the whole
 * field of quantum phenomena. As you say, "quantum physics" would be a
 * better term here; but the second usage certainly does exist.''

 * So what do you think, guys, do we
 * Move the page to quantum physics
 * Change to the popular science definition
 * Stick with the technical definition
 * I'm going for (1) - it's obviously a less ambiguous term. We can redirect from QM to QP, and put a note in QP about usage of the term QM. -- Tim Starling

In your characterization of the Prof's answer, why did you relabel his "common usage" as "technical definition" and his "alternative usage" as "popular science definition"? This seems to be a distortion to me. AxelBoldt 00:32 Nov 15, 2002 (UTC)

 * If it's a distortion then I apologise - I only meant to summarise, with labels based on my own experience of the usage of those terms. I take it by your tone that you're voting for number 3? Tim Starling

 Certain pairs of observables, for example the position and momentum of a particle, can never be simultaneously ascertained to arbitrary precision (see Heisenberg's uncertainty principle).

This is not an effect classical physics cannot account for. Rather, this is natural result of quantum theory.

Also, I think it would be better and easier to follow to move the section on the history and development of Quantum theory to the beginning of this article rather than jumping right into the theory itself. But the historical section has a lot of content relating to the philosophy, so it really must be redone. When I get a chance! MattH 10:36 25 Jul 2003 (UTC)

 * If you mean that the momentum-position uncertainty relation is not directly observable, I tend to agree. I've boldly moved the bullet point to another spot in the article. (Note, by the way, that the energy-time uncertainty relation is observable, in the form of spectral line broadening.) -- CYD

Very good! But the state is represented by a vector (or rather, by a ray) in a hilbert space only as long as it's not interacting. (A photon from a faraway star is a good approximation of it). A precise description is the density matrix, and that should in my opinion be mentioned.

Daniela

Regarding the "Schrödinger equation doesn't contain gravity" quote from Feynman:

The quote was deleted because it is, firstly, a fairly inconsequential statement about quantum mechanics, even if spoken by Feynman; and secondly because it leads to some confusion over what is meant by "Schrödinger equation". As explained in the Schrödinger equation article, the term has two slightly different meanings. Modern quantum mechanics textbooks refer to the following equation as the Schrödinger equation:

 * $$H \psi = i \hbar \frac{\partial \psi}{\partial t} \qquad\qquad\qquad\qquad\quad [1]$$

where the quantum Hamiltonian H is not necessarily specified. Let's call this equation 1. It is obeyed by any quantum mechanical system, provided H is correctly given. In contrast, when older texts refer to the "Schrödinger equation", they also mean a specific form for the Hamiltonian, i.e.

 * $$\left(- \frac{\hbar^2}{2m} \nabla^2 + V(r)\right) \psi = i \hbar \frac{\partial \psi}{\partial t} \qquad [2]$$

This second equation, which we'll call equation 2, does not describe some quantum mechanical systems. For example, the equation for a charged particle in an electromagnetic field is

 * $$\left(\frac{1}{2m}\left|- i \hbar \nabla - e A(r)\right|^2 + e \phi(r)\right) \psi = i \hbar \frac{\partial \psi}{\partial t}$$

Tim Starling's remark on my talk page, that the "Schrödinger equation" (equation 2) doesn't contain electromagnetism, is therefore not incorrect. However, it is slightly misleading, since electromagnetic systems can be described quantum mechanically, i.e. by equation 1. (We can even formulate quantum Hamiltonian for the electromagnetic field, as is done in the theory of quantum electrodynamics.)

As for gravity, equation 2 can be used to describe the motion of a particle in a gravitational field, simply by making V the gravitational potential. It cannot, however, be used to model gravitational phenomena, not even the production of a gravitational field by a particle. Whether gravity can be described quantum mechanically, i.e. by equation 1, remains an open question. -- CYD

--

I am suprised to see no mention of Bohmian Mechanics in the entry. I will preface by saying that I myself am no quantum physicist. But, as I understand, Bohmian Mechanics constitutes a coherent interpretation of quantum phenomena without the need for surmising any of the no less than bizarre accounts of reality such as 'there is no fundamental reality' or 'there are infinately many realites', the essense of the Copenhagen Interpretation and Multiple Universes respectively. From the little that I understand, Bohmian Mechanics says that it is a particle 'riding' on a wive (a pilot wave of sorts) that correctly explains experiments like the two-slit experiment (which by the way is also worth mentioning in the entry as it is the simplest and most fundamental experiment that encapsulates the basic paradox of quantum reality - that is, particle/wave duality) I see the earlier attempts at explaining quantum mechanics by way of positing 'new' or 'modified' realities as rather vein attempts to account for the paradox which had every physicist thoroughly befuddled. This is also what gave rise to those all too famous quotes, and they too should be understood in the context of that initial struggle by the scientific community to come to terms with the nature of the paradox they were faced with. But as I mentioned, I was under the impression that BM solved the paradoxical behavior of the wave/particle. -  Mike C

 * There is no paradox in QM except for the paradox of why physicists continually try to confuse the general public by using Copenhagen language to highlight the exact scenarios where the Copenhagen interpretation breaks down, then declaring "that's quantum mechanics for you". Schrödinger's equation:

 * $$H \psi = i \hbar \frac{\partial \psi}{\partial t} $$

 * is not ambiguous, so shut up and calculate.

 * yeah, who needs to use the reasoning centers of your brain to contemplate the ramifications of quantum mechanics when its much more comforting and easier to "shut up and calculate". Who needs to know whats really going on? --Brendan Stork

 * I added links to interpretation of quantum mechanics and Bohm interpretation. A short description of BM was copied from its article. -- Tim Starling 07:36, Dec 4, 2003 (UTC)

--I only meant to say that originally there was a paradox, namely, how in the world can a particle exhibit wave-like properties? This was what had everyone thoroughly baffled by the two-slit experiment. That initial bafflement and wave/particle paradox is an integral part of the history of QM and should be presented in such a context in the entry.

-secondly, Bell's theorum proved that any proposed model of quantum reality must be non-local. I feel that mentioning Bohms interpretation as non-local and as attracting little support from physicists in the same sentence will confuse the reader into the mistake that these two things are somehow connected. In fact, according to Bell, physicists must hold a non-local view of the universe and this should be no reason for them to reject BM. Furthermore, there are at least a number (how many I don't know) of respected mathematicians who now support BM. -- I recomend that we move any further discussion of the Bohm interpretation to the talk page for that entry though.

-Also, as to shut up and calculate, this seems to me to be a grievous prognostication for thwarting all further inquiry into the nature of quantum reality. If you want a perfectly analogous example to this, look at the history of Ludwig Boltzmann and atomic theory at the turn of the 20th century. He was told for decades and vehemntly renounced by the scientific community as the last man standing, holding that atomism was a model that could account for the kinetic theory of gases among other things. He was told, 'don't worry about models, that's a bunch of philosophical rubbish, just do the math' and 'you believe in something that is so small it can't be seen or measured, ludicrous'. Well eventually people went on to prove atoms existed and the microscope soon became powerful enough to study them. The point is that many thought him absurd for even trying to draw a model of reality out of the math much less one that was not observable or even measurable at that time. But if not for his stubborn insistence, it is highly likely that atomic theory would not have fully developed till much later than it did. -    Mike C

I think that some paragraphs in the section describing the theory are not entirely correct, or at best misleading. I mean the text around "During the process of wavefunction collapse...". These few paragraphs, talk about wavefunction collapse as if it's "really happening". It is well known that there is more than one interpretation of quantum mechanics that tell us what's "really happening". Even though the Copenhagen interpretation is the most commonly cited one, sooner or later it will start a heated debate as to which one should be used in the article.

I suggest rewriting that passage as follows: (a) state that experiments produce measurements that are sometimes discrete in values and the same experiment performed on the same state may result in more than one measured value. (b) explain that these experimental facts are predicted by quantum mechanics (c) offer an interpretation of these experimental facts in terms of wavefunction collapse but stress that this is only an interpretion and acknowledge other ones.

Lastly, I really don't like the sentence "During the process of wavefunction collapse, the wavefunction does not obey the Schrodinger equation." The wavefunction of a system obeys the Schrodinger equation only if it is closed (no external influences). And if a system is closed, its wavefunction always obeys the Scrodinger euqation. To avoid misconceptions, it is better to say that during the process of measurement the system can no longer be considered isolated, and the state of the measurement aparatus must be also taken into account. The analysis of measurement taking the measuring aparatus into account is called the study of decoherence and leads to results that can potentially explain the standard problem of measurement.

I'm going to think about the best way to put this into words and then make changes. I can incorporate comments if any accumulate. --igor

This is a great explanation of quantum mechanics to a lay audience, and the number of good relatively non-technical explanations quantum mechanics is shamefully small. Obviously a lot of work has gone into it, and it shows. I do have a couple of comments.

First, according to the article, "For example, an electron in an unexcited atom is pictured classically as a particle circling the atomic nucleus, whereas in quantum mechanics it is described by a static, spherically symmetric probability cloud surrounding the nucleus." This is true only for the electron whose ang. momentum quantum number is 0. I think you meant by this the electron in the Hydrogen atom...

Secondly, it would be nice if you included the photoelectric effect in the list of observations that could not be explained by classical mechanics, since this led to the idea that light is made of packets called "quanta." Also, it is for this that Albert Einstein won the Nobel prize.

Also, igo I find your comments interesting, particularly since "elementary" quantum mechanics is usually taught using the Copenhagen interpretation. It was taught this way to me, so I wasn't aware that the concept of "wave function collapse" is not intrinsic to the theory, but is rather a part of the Copenhagen interpretation. However, something observable happens to the system which is interpreted as wavefunction colapse, so how else do you refer to this observable change to make it free from any particular interpretation of quantum mechanics?

I also never realized that the Schrodinger equation only holds in a closed system-- well, it's more like I never thought about it, but of course, that makes sense-- the system becomes entangled with another, and so the "measuring" system plus the "measured" system comprise a closed system and so can be modelled with the Schrodinger equation (right?)

Assessment comment
Substituted at 21:57, 3 May 2016 (UTC)

title: Talk:Quantum mechanics/Archive 1


text:
Swan Hunter

Swan Hunter, formerly known as Swan Hunter & Wigham Richardson, is a shipbuilding design, engineering, and management company, based in Wallsend, Tyne and Wear, England.

At its apex, the company represented the combined forces of three powerful shipbuilding families: Swan, Hunter and Wigham Richardson.

The company was responsible for some of the greatest ships of the early 20th century, most famously RMS Mauretania (1906) which held the Blue Riband for the fastest crossing of the Atlantic, and RMS Carpathia which rescued survivors from RMS Titanic.

In 2006 Swan Hunter ceased vessel construction on Tyneside, but continues to provide design engineering services.

History
Swan & Hunter was founded by George Burton Hunter, who formed a partnership with the widow of Charles Sheridan Swan (the owner of a Wallsend Shipbuilding business established in 1852 by Charles Mitchell) under the name in 1880.

In 1903, C.S. Swan & Hunter merged with Wigham Richardson (founded by John Wigham Richardson as Neptune Works in 1860), specifically to bid for the important contract to build RMS Mauretania on behalf of Cunard. Their bid was successful, and the new company, Swan Hunter and Wigham Richardson Ltd, went on to build what was to become, in its day, the most famous oceangoing liner in the world. Also in 1903, the Company took a controlling interest in the Wallsend Slipway & Engineering Company, which was an early licensed manufacturer of Parsons steam turbine engines, which enabled Mauretania to achieve her great speed. Mauretania was launched from Wallsend on 20 September 1906 by the Duchess of Roxburghe. The firm expanded rapidly in the early part of the twentieth century, acquiring the Glasgow-based Barclay Curle in 1912.

In 1966, Swan Hunter & Wigham Richardson merged with Smiths Dock Company to form Associated Shipbuilders, which later became Swan Hunter Group. Following the publication of the Geddes Report recommending rationalisation in British shipbuilding, the Company went on to acquire Clelands Shipbuilding Company and John Readhead & Sons in 1967. Meanwhile, Swan Hunter inherited both the Naval Yard at High Walker on the River Tyne of Vickers-Armstrongs and the Hebburn Yard of Hawthorn Leslie in 1968. In 1973 further expansion came with the purchase of Palmers Dock at Hebburn from Vickers-Armstrongs.

Then in 1977, Swan Hunter Group was nationalised as part of British Shipbuilders. The former flagship of the Royal Navy, HMS Ark Royal (R07) was built at Swan Hunter during this period, entering service in 1985.

The Company was privatised again in 1987 but decided to close its Neptune Yard in 1988. It was then forced to call in the receivers when the UK government awarded the contract for HMS Ocean (L12) to Kvaerner Govan in 1993. The receiver took steps to break up the business. However, the main shipyard in Wallsend was bought out from receivership by Jaap Kroese, a Dutch millionaire. The yard subsequently undertook several ad-hoc ship repair and conversion projects for private-sector customers.

In 2000, Swan Hunter was awarded the contract to design and build two (Auxiliary) Landing Ship Dock ships for the Royal Fleet Auxiliary with two other ships being built by BAE Systems Naval Ships: the cost of the two Swan Hunter ships was to be £210 million including £62 million for lead yard services, with an inservice date of 2004. By July 2006, the costs had risen to £309 million and only one ship had been delivered. As a result of this, the second ship RFA Lyme Bay was transferred to BAE Systems Govan in Glasgow for completion.

In 2001, Swan Hunter acquired Kværner's Port Clarence offshore yard at Teesside but then in 2006 sold it to Wilton Engineering Group.

In November 2006, after the failure to complete Lyme Bay within budget and resulting exclusion from future Royal Navy shipbuilding projects, Jaap Kroese announced that the business was effectively finished and placed the Wallsend Yard's iconic cranes up for sale. He also said that he was actively looking for a buyer for the land. During this time, Lyme Bay's earlier sister ship, Largs Bay, was noted as the last ship to be built and fully completed by Swan Hunter. In April 2007, Swan Hunter's cranes, along with its floating dock and other equipment, were sold to Bharati Shipyards, India's second-largest private-sector shipbuilder. The entire plant machinery and equipment from Swan Hunter was dismantled and transported to India over six months to be rebuilt at Bharati Shipyards.

Swan's performed the conceptual design of Pioneering Spirit, provisionally named Pieter Schelte, the world's largest platform installation/decommissioning and pipelay vessel. The basic design of the lifting systems was completed by the end of 2008, and detailed design of the hulls by May 2010.

In 2008, the company said it was concentrating on ship design with just under 200 people employed.

In 2016, Jaap Kroese died but the company said it would continue with its business of ship design. At the time, the company had 40 employees and contractors.

Also in 2016, Swan Hunter was relaunched into the subsea industry by Gerard Kroese, the eldest son of former owner Jaap Kroese. Swan Hunter started to offer specialist equipment, design, engineering & project management services to the offshore renewables and subsea oil & gas energy markets. On 12 October 2016, the company announced the issue of a letter of intent for the design and build of a basket carousel loading tower. The company announced further equipment pool growth through a 15Te tensioner and 450Te reel drive system. Swan Hunter announced loading tower readiness on 5 May 2017 with completion of mobilisation onto EMAS Chiyoda Subsea's multi-lay vessel 'Lewek Constellation' shortly thereafter.

Operations
The Company owned three main yards: All three were on the north side of River Tyne. The company also owned the Wallsend Slipway & Engineering Company, the yard that built the engines for the Mauretania, from 1903 until the 1980s. At various times Swan Hunter also owned Palmers Hebburn Yard, Hawthorn Leslie Hebburn Yard and Readheads at South Shields which were all on the south side of the River Tyne.
 * The Neptune Yard at Walker-on-Tyne inherited from Wigham Richardson (opened in 1860 and closed in 1988)
 * The Wallsend West Yard at Wallsend inherited from Charles Sheridan Swan (opened in 1842 and closed in 2006)
 * The Naval Yard at High Walker inherited from Vickers-Armstrongs (opened in 1912 and closed during the 1980s)

Ships built by Swan Hunter
Naval vessels Commercial vessels
 * Centaur-class aircraft carrier
 * HMS Albion (R07)
 * Invincible-class aircraft carriers
 * HMS Ark Royal (R07)
 * HMS Illustrious (R06)
 * Colossus-class aircraft carrier
 * HMS Vengeance (R71)
 * Nairana-class escort carrier
 * HMS Vindex (D15)
 * King George V-class battleship
 * HMS Anson (79) (1942)
 * Town-class cruiser
 * HMS Edinburgh (16) (1938)
 * Crown Colony-class cruisers
 * HMS Gambia (48) (1940)
 * HMS Mauritius (80) (1941)
 * Acorn-class destroyer
 * HMS Hope (1910)
 * Battle-class destroyers
 * HMS Barfleur (D80)
 * HMS Corunna (D97)
 * HMS Gabbard (D47)
 * HMS Trafalgar (D77)
 * Daring-class destroyer
 * HMS Daring (D05)
 * Hunt-class destroyers
 * HMS Bolebroke (L65)
 * HMS Border
 * HMS Calpe (L71)
 * HMS Eridge (L68)
 * HMS Exmoor (L08)
 * HMS Farndale (L70)
 * HMS Grove (L77)
 * HMS Hambledon (L37)
 * HMS Heythrop (L85)
 * HMS Hursley (L84)
 * HMS Holderness (L48)
 * Tribal-class destroyer
 * HMS Somali (F33)
 * A-class destroyers
 * HMS Codrington (D65)
 * B-class destroyers
 * HMS Brilliant (H84)
 * HMS Bulldog (H91)
 * E-class destroyers
 * HMS Esk (H15)
 * HMS Express (H61)
 * H-class destroyers
 * HMS Hunter (H35)
 * HMS Hyperion (H97)
 * J-class destroyer
 * HMS Janus (F53)
 * K-class destroyer
 * HMS Khartoum (F45)
 * M-class destroyer
 * HMS Marmion (1915)
 * HMS Martial (1915)
 * HMS Mary Rose (1915)
 * HMS Matchless (1914)
 * HMS Menace (1915)
 * HMS Nessus (1915)
 * HMS Nestor (1915)
 * HMS Pasley (1916)
 * U and V-class destroyer
 * HMS Grenville (R97)
 * HMS Ulster (R83)
 * HMS Vigilant (R93)
 * HMS Virago (R75)
 * V-class destroyers
 * HMS Vimiera (1917)
 * HMS Violent
 * HMS Vittoria (1917)
 * W-class destroyers
 * HMS Whirlwind (1917)
 * HMS Wrestler (1918)
 * Type 82 destroyer
 * HMS Bristol (D23)
 * Type 42 destroyers
 * HMS Newcastle (D87)
 * HMS Glasgow (D88)
 * HMS Exeter (D89)
 * HMS York (D98)
 * Type 14 (or Blackwood-class) anti-submarine frigates
 * HMS Russell (F97)
 * HMS Pellew (F62)
 * Type 22 frigates
 * HMS Chatham (F87)
 * HMS Coventry (F98)
 * HMS Sheffield (F96)
 * Type 23 frigates
 * HMS Marlborough (F233)
 * HMS Westminster (F237)
 * HMS Northumberland (F238)
 * HMS Richmond (F239)
 * Hastings-class sloop
 * HMS Scarborough (L25)
 * Ness-class combat stores ship
 * RFA Lyness
 * RFA Stromness
 * RFA Tarbatness
 * Fort Victoria-class replenishment oiler
 * RFA Fort George
 * Rover-class tankers
 * RFA Black Rover (1973)
 * RFA Gold Rover (1973)
 * Bay-class landing ships
 * RFA Largs Bay
 * RFA Lyme Bay – Completed by BAE Systems
 * IRIS Kharg (1977)
 * SS Abukir (1920)
 * Achiever (circa 1984)
 * SS Afrique (1907)
 * Antarctic (1913)
 * Arawa (1907)
 * Ariosto (1940)
 * Atlantic Causeway (1969)
 * Atlantic Conveyor (1970)
 * Augustina (1927)
 * Aurania (1916)
 * Ascania (1911)
 * Badagry Palm (1) (1956)
 * Bamenda Palm (1) (1958)
 * Bello (1930)
 * British Admiral (1917)
 * British Character (1941)
 * British Coast (1919)
 * British Colony (1927)
 * British Diligence (1937)
 * British Dominion (1928)
 * British Empress (1917)
 * British Endurance (1936)
 * British Fame (1936)
 * British Fusilier (1923)
 * British Governor (1926)
 * British Gratitude (1942)
 * British Grenadier (1922)
 * British Gunner (1922)
 * British Harmony (1941)
 * British Hussar (1923)
 * British Influence (1939)
 * MV British Motorist (1924)
 * British Petrol (1925)
 * British Pluck (1928)
 * British Resolution (1937)
 * British Respect (1943)
 * British Sailor (1918)
 * British Scout (1922)
 * British Star (1918)
 * British Tenacity (1939)
 * British Thrift (1928)
 * British Union (1927)
 * British Virtue (1945)
 * British Viscount (1921)
 * CA Larsen (1913)
 * RMS Carpathia (1902)
 * City of Canterbury (1922)
 * City of Lyons (1926)
 * City of Oxford (1926)
 * City of Paris (1922)
 * Corte (1906)
 * Coslar (1906)
 * MV Derbyshire (1976)
 * Dimboola (1912)
 * QSMV Dominion Monarch (1938)
 * TSS Dover (1965)
 * MV Duntroon (1935)
 * SS Dwarka (1947)
 * Elmina Palm (1957)
 * Enugu Palm (1958)
 * Franconia (1910)
 * Frontenac (1928)
 * Germanic (1931)
 * Ghandara (circa 1976)
 * Ibadan Palm (1959)
 * Ikeja Palm (1961)
 * Ilesha Palm (1961)
 * Ilorin Palm (1959)
 * Inanda (1925)
 * Imbricaria (1935)
 * SS Ivernia (1899)
 * Jean Brillant (1935)
 * Kano Palm (1958)
 * Katsina Palm (1957)
 * Kittiwake (1906)
 * RMS Knight of Malta (1929)
 * MV Kowloon Bridge (1973)
 * SS Kyle (1913)
 * RMS Laconia (1911)
 * RMS Laconia (1921)
 * Lagos Palm (1961)
 * TS Leda (1952)
 * Lida (1938)
 * Lindenfels (1906)
 * Lobito Palm (1960)
 * Lowenburg (1907)
 * Matadi Palm (1970)
 * RMS Mauretania
 * Megantic (1962)
 * SS Miraflores (1921)
 * Mitra (1912)
 * Moyra (1931)
 * Mytilus (1916)
 * Neverita (1944)
 * Nidarnes (1926)
 *  Northenden (1886) For Manchester Sheffield and Lincolnshire Railway - later Great Central Railway
 * Opopo Palm (1942)
 * SS Port Adelaide (1911)
 * SS Port Alma (1928)
 * MS Port Auckland (1949)
 * MS Port Brisbane (1949)
 * MS Port Chalmers (1933)
 * SS Port Elliot (1910)
 * MV Port Fairy (1928)
 * MS Port Gisborne (1927)
 * MS Port Halifax (1937)
 * MS Port Hobart (1925)
 * MS Port Huon (1927)
 * MS Port Jackson (1937)
 * MS Port Lincoln (1946)
 * MS Port Macquarie (1944)
 * MS Port Napier (1940)
 * MS Port New Plymouth (1960)
 * MS Port Phillip (1942)
 * MS Port Pirie (1947)
 * MS Port Sydney (1955)
 * MS Port Townsville (1935)
 * MS Port Victor (1942)
 * MS Port Vindex (1944)
 * Powerful (1903)
 * SS Prince George (1910)
 * SS Prince Rupert (1910)
 * Príncipe Perfeito (1961)
 * Provence (1951)
 * Ranella (1912)
 * TEV Rangatira
 * Rauenfels (1907)
 * SS Reina Victoria-Eugenia (1912)
 * Rosalind (1890)
 * Saint Clair (1929)
 * Sir Parkes (1951)
 * South Africa (1930)
 * Spartan (1890)
 * Stephano (1965)
 * Toiler (1910)
 * Venezia (1907)
 * SS Victoria (1902)
 * Vikingen III (1929)
 * Vistafjord (1972)
 * SS Volo (1938)
 * Waterford (1912)
 * SS Warrington (1886) For Manchester Sheffield and Lincolnshire Railway – later Great Central Railway)
 * Zenda (1932)

Cable ships
 * Alert
 * All America
 * Ariel
 * Bullfinch
 * Bullfrog
 * Bullhead
 * Cambria
 * Colonia
 * Dominia
 * Edward Wilshaw
 * Emile Baudot
 * Guardian
 * Iris
 * John W. Mackay
 * Lord Kelvin
 * Marie Louise Mackay
 * Monarch
 * Pacific Guardian (1984)
 * Patrol
 * Recorder
 * Sir Eric Sharp (Launched 1988 – renamed CS IT Intrepid )
 * St. Margarets
 * Stanley Angwin
 * Telconia

Bulk Carrier
 * Hoegh Duke (1984)
 * Robkap IV (1977)
 * Liverpool Bridge Renamed to the MV Derbyshire (1976)

Research Vessels
 * CSS Acadia (1913)
 * HMCS Cartier (later renamed HMCS Charny)
 * RRS James Clark Ross Polar survey

Tankers
 * Shell Supplier (1946)
 * ARA Punta Médanos (1950)
 * Velutina (1950)
 * Velletia (1952)
 * Helix (1953)
 * Helcion (1954)
 * Heldia (1955)
 * Helisoma (1956)
 * Volvula (1956)
 * Llanishen (1957)
 * Zaphon (1957)
 * Varicella (1959)
 * Solen (1961)
 * Ottawa (1964)
 * Sir Winston Churchill (1964)
 * Clementine Churchill (1965)
 * Narica (1967)
 * Nacella (1968)
 * Esso Northumbria (1969)
 * Esso Hibernia (1970)
 * Faraday (1970) Liquified petroleum gas tanker
 * Texaco Great Britain (1971)
 * London Lion (1972)
 * Frank D. Moores (1973)
 * World Unicorn (1973)
 * Windsor Lion (1974)
 * Tyne Pride (1975)
 * Everett F. Wells (1976)
 * BP Achiever (1983)

Battleship Potemkin
On 1 May 2006, British pop-duo Pet Shop Boys performed their soundtrack to the 1925 Soviet silent-film Battleship Potemkin alongside the Royal Northern Sinfonia at the shipyard.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Swan Hunter


text:
Battle of the North Foreland

Two naval battles of the Anglo-Dutch Wars are called the Battle of the North Foreland after the cape on the Kent coast of England:
 * The Battle of the Gabbard, June 12 to June 14, 1653, in the First Anglo-Dutch War.
 * The St. James's Day Battle, August 4 to August 5, 1666, in the Second Anglo-Dutch War.

There was also a Battle of South Foreland fought between English and French fleets in 1217.

title: Battle of the North Foreland


text:
Rear of the Year

Rear of the Year was a British award for celebrities who were considered to have attractive buttocks. It was created by publicity consultant Anthony Edwards in 1976. Initially, it was awarded only to women, but in 1986 the first award was made to a man and from 1997, it was awarded annually to one woman and one man.

The award was organised by Rear of the Year Limited. The last contest was held in 2019, and Rear of the Year Limited was dissolved as a company in 2021.

History
Edwards initiated the award as a way to promote specific brands of jeans. Barbara Windsor won the first award in 1976, which was presented as a one-off publicity stunt. Five years later it became an annual event with Felicity Kendal receiving the honours. The 1982 winner Suzi Quatro commented: "I’ve been told since I was about eight or nine that I had a nice ass... So, when I won the award, I was actually quite proud." The singer Lulu, who won the 1983 award, was later asked by a journalist if she felt that she had been the subject of objectification when she won the award, and replied: 'I think you're taking this all much too seriously'. On winning the award in 1985, Lynsey de Paul quipped "I would like to thank the organisers from the heart of my bottom". In 1986, the award was presented to a man for the first time (Michael Barrymore) and 1991 saw Marina Ogilvy, the daughter of Princess Alexandra, became the first royal recipient. A male award was given to Richard Fairbrass in 1994 and from 1997 the male award became a regular part of the annual event. The 2002 award to Charlotte Church attracted controversy as the winner had only recently turned 16 at the time.

2010 winner Fiona Bruce accepted the award and participated in a photoshoot, happily posing for pictures in tight jeans. However, she subsequently described the award as "the most hypocritical, ridiculous, ludicrous thing I’ve ever done."

In 2014, Carol Vorderman became the first person to receive the award for a second time, joking: "I always suspected there were a lot of people out there who were glad to see the back of me. It now appears there were even more than I thought."

The winners of the award were selected by public vote, a process that sometimes accrued popular campaigns for particular individuals. The winners were usually actors in soap operas, contestants in reality TV shows or pop stars. Edwards has described the contest as "an excellent monitor of fashions in body shape". In 2012 he declared that female rears were starting to slim down as more women took to the gym, jogging and keeping trim during that Olympic year. In 2018 he said that "the trend is towards a shapely, well-toned and, above all, proportionate rear".

A number of businesses sponsored the award including manufacturers of beauty products, Cadbury and Wizard Jeans. By 2015 the award was reported to be generating a level of media coverage equivalent to £4 million (US$ million) Advertising Value Equivalent.

Award winners were given a commemorative plaque in the form of an engraved crystal trophy. Until 2016 the award was promoted with a winner's photo op that was reported in the UK's tabloid newspapers. The event, staged for some years at The Dorchester hotel in London, was attended by numerous press photographers and included a champagne reception. Some winners subsequently described ambivalent feelings about their photo ops, during which they were photographed from behind. 2007 winner Siân Lloyd described hers as "probably the weirdest photocall I’ve attended in my life", while 2003 winner Natasha Hamilton said of seeing her pictures in the press: "I just didn’t like it. It seemed a little bit crass and seedy."

Winners
Recipients included:

 * 1976 — Barbara Windsor
 * 1981 — Felicity Kendal
 * 1982 — Suzi Quatro
 * 1983 — Lulu
 * 1984 — Elaine Paige
 * 1985 — Lynsey de Paul
 * 1986 — Anneka Rice and Michael Barrymore
 * 1987 — Anita Dobson
 * 1988 — Su Pollard and Steve Davis
 * 1989 — No competition
 * 1990 — No competition
 * 1991 — Marina Ogilvy
 * 1992 — Ulrika Jonsson
 * 1993 — Sarah Lancashire
 * 1994 — Mandy Smith and Richard Fairbrass
 * 1995 — No competition
 * 1996 — Tracy Shaw
 * 1997 — Melinda Messenger and Gary Barlow
 * 1998 — Carol Smillie and Frank Skinner
 * 1999 — Denise van Outen and Robbie Williams
 * 2000 — Jane Danson and Graham Norton
 * 2001 — Claire Sweeney and John Altman
 * 2002 — Charlotte Church and Scott Wright
 * 2003 — Natasha Hamilton and Ronan Keating
 * 2004 — Alex Best and Aled Haydn Jones
 * 2005 — Nell McAndrew and Will Young
 * 2006 — Javine Hylton and Ian Wright
 * 2007 — Siân Lloyd and Lee Mead
 * 2008 — Jennifer Ellison and Ryan Thomas
 * 2009 — Rachel Stevens and Russell Watson
 * 2010 — Fiona Bruce and Ricky Whittle
 * 2011 — Carol Vorderman and Anton du Beke
 * 2012 — Shobna Gulati and John Barrowman
 * 2013 — Flavia Cacace and Vincent Simone
 * 2014 — Carol Vorderman and Olly Murs
 * 2015 — Kym Marsh and Daniel Radcliffe
 * 2016 — Jennifer Metcalfe and Tom Hiddleston
 * 2017 — Rachel Riley and Idris Elba
 * 2018 — Michelle Keegan and Aidan Turner
 * 2019 — Amanda Holden and Andy Murray

Similar contests

 * In 2013, a University of Cambridge newspaper held its own version of the award in which the contestants were naked.

 * Miss Bumbum is an annual contest in Brazil to choose the best female buttocks in the country.

title: Rear of the Year


text:
Vinayagar Agaval

Vinayagar Agaval is a devotional poetic hymn to the Hindu deity Ganesha. It was written in the 10th century during the Chola dynasty by the Tamil poet Avvaiyar, shortly before her death. It is considered to be her greatest poem. The 72-line 'Agaval' is a form of blank verse, close to speech.

Vinayagar Agaval defines a religious path, part of the Tamil devotional tradition of Bhakti, within the Hindu philosophy of the Shaivite sect. Its application as a spiritual tool begins during concentration on a physical image of Ganesha and continues with the use of the Agaval's description of Hindu spiritual belief and practice, and aspects of the teachings on human life attributed to the deity. "சீதக்களபச் செந்தாமரைப் பூம்

பாதச்சிலம்பு பலவிசை பாட

பொன்னரை ஞாணும் பூந்துகில் ஆடையும்

வன்ன மருங்கில் வளர்ந்தழகெரிப்பப்"

"seedhakkaLapach chendhaamaraip poom

paadhachchilampu palavisai paata

ponnarai gnaaNum poondhukil aataiyum

vanna marungil vaLarndhazhakerippap"

meaning is, the Lotus feet of Ganesha having the color of red lotus, and which is besmeared with cool sandal is adorned by anklets, sings various songs.golden waist belt and his clothes as soft as flower shine like beautiful colors in the rainbow.

According to Chandrasekarendra Swamigal, a person reciting the Vinayagar Agaval every day will realize highest wisdom.

Full Text
The full text of the Vinayagar Agaval published in Maalai Malar. Since this text is from 10th century CE, it is not governed by any copyright law. Vinayagar Agaval consists of 120 verses written in Tamil, each verse carefully crafted to convey deep spiritual truths. The hymn beautifully describes the form and attributes of Lord Ganesha, exalting his divine qualities and significance. The verses also reflect upon the nature of human existence, the challenges faced on the spiritual path, and the ultimate goal of attaining liberation from worldly attachments.

Lyrics in Tamil]
சீதக் களபச் செந்தா மரைப்பூம்

பாதச் சிலம்பு பலஇசை பாட

பொன்னரை ஞாணும் பூந்துகில் ஆடையும்

வன்ன மருங்கில் வளர்ந்தழ(கு) எறிப்ப

பேழை வயிறும் பெரும்பாரக் கோடும்

வேழ முகமும் விளங்குசிந் தூரமும்

அஞ்சு கரமும் அங்குச பாசமும்

நெஞ்சில் குடிகொண்ட நீல மேனியும்

நான்ற வாயும் நாலிரு புயமும்

மூன்று கண்ணும் மும்மதச் சுவடும்

இரண்டு செவியும் இலங்குபொன் முடியும்

திரண்டமுப் புரிநூல் திகழ்ஒளி மார்பும்

சொற்பதம் கடந்த துரியமெய்ஞ் ஞான

அற்புதம் நின்ற கற்பக் களிறே!

முப்பழம் நுகரும் மூஷிக வாகன

இப்பொழுது என்னை ஆட்கொள வேண்டித்

தாயாய் எனக்குத் தானெழுந்(து) அருளி

மாயாப் பிறவி மயக்கம் அறுத்துத்

திருந்திய முதல்ஐந் தெழுத்தும் தெளிவாய்ப்

பொருந்தவே வந்தென் உளந்தனில் புகுந்து

குருவடி வாகிக் குவலயந் தன்னில்

திருவடி வைத்துத் திறம் இதுபொருள்என

வாடா வகைதான் மகிழ்ந்தெனக் கருளிக்

கோடா யுதத்தால் கொடுவினை களைந்தே

உவட்டா உபதேசம் புகட்டிஎன் செவியில்

தெவிட்டாத ஞானத் தெளிவையுங் காட்டி

ஐம்புலன் தன்னை அடக்கும் உபாயம்

இன்புறு கருணையின் இனிதெனக் கருளிக்

கருவிகள் ஒடுங்கும் கருத்தினை அறிவித்(து)

இருவினை தன்னை அறுத்திருள் கடித்து

தலமொரு நான்கும் தந்தெனக் கருளி

மலமொரு மூன்றின் மயக்கம் அறுத்தே

ஒன்பது வாயில் ஒருமந் திரத்தால்

ஐம்புலக் கதவை அடைப்பதுங் காட்டி

ஆறா தாரத்து அங்குச நிலையும்

பேறா நிறுத்திப் பேச்சுரை அறுத்தே

இடைபிங் கலையின் எழுத்தறி வித்துக்

கடையில் சுழிமுனைக் கபாலமும் காட்டி

மூன்றுமண் டலத்தின் முட்டிய தூணின்

நான்றெழு பாம்பின் நாவில் உணர்த்திக்

குண்டலி அதனில் கூடிய அசபை

விண்டெழு மந்திரம் வெளிப்பட உரைத்து

மூலா தாரத்து மூண்டெழு கனலைக்

காலால் எழுப்பும் கருத்தறி வித்தே

அமுத நிலையும் ஆதித்தன் இயக்கமும்

குமுத சகாயன் குணத்தையும் கூறி

இடைச்சக் கரத்தின் ஈரெட்டு நிலையும்

உடற்சக் கரத்தின் உறுப்பையுங் காட்டிச்

சண்முக தூலமும் சதுர்முக சூட்சமும்

எண்முக மாக இனிதெனக்(கு) அருளிப்

புரியட்ட காயம் புலப்பட எனக்குத்

தெரிஎட்டு நிலையும் தரிசனப் படுத்தி

கருத்தினில் கபால வாயில் காட்டி

இருத்தி முத்தி இனிதெனக்கு அருளி

என்னை அறிவித்து எனக்கருள் செய்து

முன்னை வினையின் முதலைக் களைந்து

வாக்கும் மனமும் இல்லா மனோலயம்

தேக்கியே என்றன் சிந்தை தெளிவித்து

இருள்வெளி இரண்டும் ஒன்றிடம் என்ன

அருள்தரும் ஆனந்தத்தை அழுத்திஎன் செவியில்

எல்லை இல்லா ஆனந்தம் அளித்து

அல்லல் களைந்தே அருள்வழி காட்டிச்

சத்தத்தின் உள்ளே சதாசிவம் காட்டிச்

சித்தத்தின் உள்ளே சிவலிங்கம் காட்டி.

அணுவிற்கு அணுவாய் அப்பாலுக்(கு) அப்பாலாய்க்

கணுமுற்றி நின்ற கரும்புள்ளே காட்டி

வேடமும் நீறும் விளங்க நிறுத்திக்

கூடுமெய்த் தொண்டர் குழாத்துடன் கூட்டி

அஞ்சக் கரத்தின் அரும்பொருள் தன்னை

நெஞ்சக் கருத்தின் நிலையறிவித்துத்

தத்துவ நிலையைத் தந்தெனை ஆண்ட

வித்தக விநாயக! விரை கழல் சரணே!.

Translation (Lyrics in English)
Cool, white and fragrant lotus like feet, with anklets tinkling sweet in multitude beat, gold girdle, garments as soft as flower, colorfully wrapping your comely hips lower,

belly like a pot and big, heavy tusk, elephant-face with the perfect red mark, five hands, the goad, the noose in hands apart, dwelling divine beautiful blue body in my heart,

With pendulous mouth and one with four mighty shoulder, having three eyes that denotes three sect marks bolder, two ears, the gold crown gleaming on your head, the breast glowing with the holy triple thread.

Oh divine turya knowledge, Beautiful beyond word, who came as wish-fulfilling elephant, we heard. Oh mouse-rider, fond of the three famed fruit, desire to make me yours this instant, takes root,

Having appeared before me, like a mother, Cutting delusion of unending births, not another. imprinting the five prime letters, clearly, You have come and entered my heart, dearly.

Stepped in the form of a teacher, into my world, Thine divine feet, pointing to the priceless, gold, With the divine knowledge without fatigue, blessed, With that unfailing weapon, my heinous sins, severed.

Uncloying pure precepts, poured in my ear, clarity of ever-fresh awareness, laid bare - for firm control of all of my senses, five, out of kindness, thou have blessed me high.

Brought the idea of the organs of action, controlled, snapped my two-fold karma and my darkness dispelled, a place for me in all four states, your grant, dissolved the illusion of triple filth,

Using a single name over the temple with nine-door, five-door senses now under control, free no more, fixed me firm in all of the six yogic center, Stabilized in myself, speechless joy, I enter.

of ida and pingala, having been introduced, last the head of sushumna, to me, you showed, three bright spheres of sun, moon and fire, To the tongue of the serpent that sinks and soar.

Having achieved the energy of Kundali assemblage, and explicitly uttered it purely through your grace; flame of muladhara, collected in me and raging, imparted the skill of breath, steadily rising.

The state of immortality, the sun's moving trend and the charm of the moon; the water lily's friend, the sixteen states of the chakras intermediary, revealed to me in thoughtful wisdom in my body.

the six-faced form and four-faced body subtle, and the eight separate modes of my eternal soul; Given me understanding of subtle body that is divine, Miraculous powers, my mind is open to your design.

the never-closing gateway of Brahman opened so, You have also given me the final mukti, too; revealed my Self to me and by your grace My accumulated karma, swept of the base.

State beyond speech and thought, in tranquil calm You clarified my intellect, this is now my form. making me experience, at the spot between two eyes, through your divine blessing, between my ears, bliss.

You have given me the state of boundless elation, showing me the way of grace, ending all affliction, As the core of the sound Om, I have seen Sadasiva, At the core of my mind, you have shown me lingasiva.

atom within atom, vast beyond all vastness, hid in the hardened node, having tasted sweetness. You have steadied me clear in human form, devoid of duality, added me to the congregation of your servants true and trusty.

Of the Five-handed one, the absolute true essence, You have given it to me in my heart, the experience, restored my real state to me; and will rule me now, Oh Master of Wisdom, Vinayaka, to thine feet alone, I bow, Oh Master of Wisdom, Vinayaka, to thine feet alone, I bow.

title: Vinayagar Agaval


text: User talk:81.135.124.158

title: User talk:81.135.124.158