The interpretation tells, that light is wave, which becomes the photons only on the target/screen. Note, that photons on screen are at rest, however there are no photons at rest: thus, there are only waves and none photons - according to copenhagen interpretation. However, there are photons: thus, the copenhagen interpretation is nonsense. Back to first sentence. The de Broglie hypothesis p = h/\lambda tells, that light is in the same time both photons and wave: to any particle corresponds the wave, not the particle transforms into wave (in latter process the particle is surely partly wave and partly photon). Thus, it is enemy of copenhagen interpretation, which supposes, that light is wave or photons and not both of these the same time.
Dear Dmitri, in my humble opinion, Copenhagen interpretation tells us that electron or light can behave like wave or particles, depending on the experimental setup. This is often called wave particle duality hypothesis. This is different from De Broglie's Nobel lecture, which was given title: Wave nature of electron.
So basically, i do not have problem with the wave nature of electron, which can be modelled using wave equation or Helmholtz equation.
But Copenhagen interpretation created many problems such as complementarity principle, mind-matter interaction, collapse of wave function, probabilistic interpretation of wavefucntiin etc, with cannot be easily resolved until now. Therefore i agree with you tha Copenhagen interpretation should be rejected. Best wishes
The wave corresponding to photons is a probability wave, which gives the probability amplitude of detecting at any point. When a photon is detected on a screen it is not at rest, but rather destroyed, due to disturbance created by the measurement.
I think both interpretations are correct and not enemies of each other, but rather complement each other. Furthermore the wave given by de-Broglie is a matter wave and has no classical analogies. It only gives information regarding probabilities corresponding to the variable under measurement, be it momentum, position etc.
Take for example compton scattering. It can be explained by taking the photon as a wave as well as a particle!!
"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy." (William Shakespeare, Hamlet, Act 1. Scene V). The quasi-static electric charges do have the field around them, which follows the law of Maxwell. This field is not the mathematical probability, nor it has the virtual photons. Let us very gently and slowly to shake the electric charges. Obviously the values of the field will continuously change. Thus, there are waves, which are not photons nor probabilities. The David Bohm would say, that it is kind of quantum potential. I say, that it all under control and fine tuning of the God. This all is called: Grace.
Copenhagen interpretation and its central concept of complementarity, but they proposed to modify it by introducing certain approximations in the limit of large numbers. Some, clearly pointed out the statistical hypothesis that was being used and proposed to simply substitute it for the projection postulate.
Copenhagen interpretation says that physics does not deal with things but with measurements. That tastes like idealism, and is therefore rejected by the communists. Vice versa also applies, since anyone here in the West who doubts the orthodox interpretation – even for objective reasons – is suspect of communism. All this with the complexities and meaninglessness of a religious war, complete with converts: the greatest defender of the orthodoxy is a communist [Rosenfeld], and many in the opposition are fully bourgeoise
http://www.docentes.unal.edu.co/ahdegreiffa/docs/Tausk-Pessoa_Freire_DeGreiff.pdf
To Victor. Thanks! I quote from your file: "Thus to describe the properties of matter as well as those of light, waves and corpuscles have to be referred to at one and the same time." (LOUIS DE BROGLIE, 1929). There can not be a multiple valued logic, despite the article in Wikipedia. There can be multiple variants, but the logic has only "No/Yes" as the answer to a variant. Wave is not particle. Thus, there is Alogismus (German wikipedia), which, thus, is impossible in nature. The God is above the nature, in latter the logic law is valid. Here in quote the DE BROGLIE starts dictatorship: "on this concept of the duality of waves and corpuscles... all future development of this science will apparently have to be founded." From this came some dictator lines in the American Physical Review, which, I am sure, will reject my paper "Can Niels Bohr's Philosophy be Wrong?" (viXra:1409.0177), at least the Phys.Rev. has not suggested to publish it.
Don't be so complex, Charles Francis. It is honor to work in Jesus College, isn't it? God does not want us to use the multi-logic: "All you need to say is simply "Yes" or "No"; anything beyond this comes from the evil one." (Matthew 5:37 NIV). Multi-valued way of thinking (Russian: "yes-no-perhaps") is not logic. To your example: "he is a tall man". To make my logical decision (Yes/No), I ask You: what meaning has the word "tall"? Is it high in centimeters, or proud like a fool? Then I will ask You to show me him. Then I can judge verity of your statement: is it Yes, or No. 2) I am sure the probability theory, Bohm's Quantum Mechanics and statistics can live happily within the natural logic.
To quote your question: "--which becomes photons only on the target screen". From here you argued that there can be no photons at rest and hence there are no photons.
You are wrong here!! The wave doesn't become photons, it only gives the information where the photon will be detected!! Asking the question: where was the photon before detection?? It was everywhere. It was our detection which forced it to localise at a certain point.
Secondly you mention that wave becomes a photon at screen and it is at rest. To this, the wave doesnt transform into photon as explained above and secondly once the photon is detected it is " destroyed". There are certainly no photons at rest. What you observe on the screen is only an electric impulse (photodetector), and not a photon at rest.
Photon exists as a wave, but once forced to localise it will become a particle. This is true for all particles as such.
So accordingly both copehagen approach and de-Broglie approach are the same--"according to the scenario as you proposed."
Let's follow next definition:
http://en.wikipedia.org/wiki/Copenhagen_interpretation
Copenhagen interpretation says that wavefunction collapses during measurement.
De Broglie simply gives a formula for the wavelength of any particle, see here:
http://physics.niser.ac.in/~sbasak/p303_2010/06.08.pdf
The problem with 'Copenhagen' is that assigns a physical existence to pure mathematical objects that are used to describe reality in the frame of linear algebra. From this point of view, it has nothing to do with de Broglie's definition.
Charles Francis directed us to the example "there will be a sea battle tomorrow". Me: Yes, it is possible to be: Putin vs. Obama because of Ukraine question. See, just like the Jesus Christ has recommended, I have responded with "Yes". If You ask: "will there be a sea battle tomorrow?", I will ask back: "are there any reasons?". You: Obama and Putin are arguing. Me: Yes, the battle is possible. And again, I say "Yes", just like the Jesus instructed me. You: will battle happen for sure, with 100 %? Me: Because I believe in Good Will of our Free World presidents, I answer with definite "No".
Louis de Broglie, Schrödinger and many others struggled against wave-particle duality. De Broglie proposed to correct, except at infinity, the waves found from Schrödinger equations, but he failed.
The reason is that he tried to compute what we name now "soliton", which are solutions of non-linear equations. Now, we remain unable to study precisely the solitons.
The problem of mathematics that we remain unable to solve was transformed into a problem of physics, the absurd duality.
Waves and particles are both *classical* entities. A wave is the coolective motion of many particles. A particle is a well localized essentially structureless mass point with a given velocity. Saying that a quantum particle obeys ``wave-particle duality'' or is ``sometimes a wave and sometimes a particle'' is a very misleading way of refusing to acknowledge that a quantum particle is something quite different from either waves or particles. Any attempt to understand quantum particles in terms of either waves or particles is doomed. To that extent, both the initial papers of Bohr and certainly the work of de Broglie represented historically very important advances, but they should not be considered today by anybody who wishes to understand quantum mechanics (as opposed to understanding its history): too much has changed, both in our understanding of the formalism and in our experimental knowledge, for anyone to consider such ideas as having more than historic interest.
A quantum particle moving over large distance at high velocities can mimic quite well the behaviour of a classical particle. A large number of particles (specificallly Bosons) moving coherently can mimic a classical wave. Thus classical electromagnetic waves, as generated by the gentle motion of a charge, consists of a large number of photons moving coherently and behaving much as a wave. Similarly, an atom moving at not too low speeds behaves like a classical particle.
However, we can describe quantum particles. It is just that the description does not operate using concepts that are easily expressible in classical terms. But one can readily compute quite accurately the answer to any given precisely posed problem. The basic concept is that of state: the state of a system is a set of complex amplitudes associated to some description of the system's configurations. If a system has, say, 3 particles, then the system's having particle 1 at q1, particle 2 at q2 and particle 3 at q3 has a given *complex* amplitude a(q1, q2, q3).
Note tha a(q1, q2, q3) cannot be a wave, as is often thought. This is immediate if you note that, if the particles move in three-dimensional space, q1, q2 and q3 all have 3 coordinates, so that a(q1, q2, q3) has nine arguments. A wave, of course, could never have more than 3 arguments.
The probability of the system's being in that configuration is the squared modulus of that complex amplitude. The phases of these amplitudes, particularly in the way they vary over space, describe conjugate features to the original system's description. In that case, the phases' spatial variations describe the particles' momenta.
How one measures properties of quantum states is perhaps the one problem in quantum mechanics where some interpretation problems persist. However, great steps forward have been made. Essentially, the interaction of a quantum system with any kind of large uncontrolled environment produces effects which in many respects can be described as the ``collapse of the wave function''. These effects are known as decoherence. In this way, many of the problems related to the measurement problem have been solved. Some truly peculiar features arise in systems violating Bell's inequalities. However, there are no contradictions, only situations in which one wonders how such effects could come to pass. But to resolve these problems, the wave-particle talk is utterly useless. Quantum mechanics is neither about waves nor particles: it is about quantum systems and their states.
@F. Leyvraz
My respect: you have astronomically high RG reputation. It is certainly the honor to talk to you in my humble place. I like the David Bohm's theory. Therefore, I fight the Bohr's philosophy. So the reasons for my activity are clear, therefore please do not be angry with my production.
F. Leyvraz: "If a system has, say, 3 particles, then the system's having particle 1 at q1, particle 2 at q2 and particle 3 at q3 has a given *complex* amplitude a(q1, q2, q3)... Quantum mechanics is neither about waves nor particles: it is about quantum systems and their states." Me: 1) a man from the street, would see, that these two sentences are incompatible. 2) even if initially the particles are in clear separation, the further evolution makes such illogical situation: in given spacetime point can be all three particles: there is non zero probability for such event. Is this correct? 3) the Bohr's philosophy has difficulties, see my contributions in "homepage".
" a man from the street, would see, that these two sentences are incompatible": why? one of those sentences says that the assignment of complex amplitudes to system configurations is a state. The second sentence says that QM is about states. No contradiction intended. In fact, I had even another sentence saying explicitly that a(q1, q2, q3) cannot be a wave. It is a state.
2) This is incorrect. The probability of 3 (or even two) particles being excatly at the same point is always zero. However, if we have no repulsion between the particles, the probability density of this may be nonzero. But why should this be illogical?
3) My main point is that we should not so much refer to Bohr, since interpretation of QM has changed significantly since Bohr. So Bohr, and particularly ``Bohr's philosophy'' are not very useful things to consider. The main difficulties with QM nowadays come from issues which Bohr hardly ever discussed, and from questions which arose, historically, much later. So whatever problems you find in Bohr's philosophy, may not be relevant to present day issues in QM. In particular, I wanted to make the point that wave-particle duality, while it may have been important in the thirties, is not really a useful way to think about QM.
@F. Leyvraz: "why? one of those sentences says that the assignment of complex amplitudes to system configurations is a state. The second sentence says that QM is about states." Me: my view of logic is following. System configuration is a state, which mathematics contains the complex amplitudes. I argue, that the state is system configuration (of particles). Because QM is about states, then QM is about particles. P.S. The David Bohm theory uses particles.
Are copenhagen interpretation and de Broglie hypothesis enemies?
I don not think they are enemies. It is true that the Copenhagen interpretation was considered as such by the Copenhagen believers. But that is as unjustified as it is unjustified to consider a rigid body description of a billiard ball an enemy of an atomic solid state description of such an object. They are just descriptions corresponding to different physical levels on which the same object can be studied.
PhD Charles Francis: "we know of the system configuration, not the system configuration itself." Me: Thank you for the true honor of having persons with such high RG reputation. Dr. Leyvraz refers to function of state a(q1,q2,q3), where q1 are space coordinates of first particle, q2 - second, and q3 are the coordinates of the third one. Thus the QM really is about the particles at definite, precise positions. I mean, that the very definition of state-function includes the word "particle".
¨my view of logic is following. System configuration is a state¨. That may indeed be logical, but it is not what QM says. In the definition of state in QM, you need to assign a given amplitude to all possible configurations of the system. That is why I said that a state is an assignment of amplitudes to all possible system configurations.
As to Bohm's interpetation, you are of course right, it involves particles, among others. But the QM wave function, the assignment of complex amplitudes to all possible system configurations, is also necessary in Bohm's version of QM.
As for my use of the word particle, in the definition of a state: a(q1, q2, q3) is the amplitude of having particle 1 at q1, etc... It may have been an unfortunate choice of words: clearly, the concept of particle in quantum mechanics is different from the same concept in classical mechanics. It would perhaps have been better to say ``having quantum particle 1 at position q1 etc...'' In any case, my argument was that we should consider states as a way of describing physical systems different from either a wave or a classical particle picture of reality.
To my not quite humble opinion, the reality takes in some extent the regard of our theories. It is not direct link between our fantasies and reality. The God's decision is in between. Such is the target I was directing your minds all the above comments. Thank You for attention to my sinful soul.
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