Light, wave/particle problem

Einstein s idea started a truly revolutionary development in physics quantum mechanics, It opened up wide new horizons and clarified many outstanding problems in our view of the structure of matter, Quantum mechanics is based on the idea of wave-particle duality. Einstein first applied this idea to the nature of light, but it was... 

And what does that mean In the 1920s Louis DeBroglie described electrons as both particles and waves because they have precise mass, go splat-splat-splat (or click-click-click ) into Geiger counters yet show interference like radio and light waves. It is one thing to say particle-waves and quite another to really picture them. Try it. Our problem is that electrons are outside of both our direct senses and experiences. As Bronowski notes, twentieth-century physics introduced abstraction and uncertainty and the need for what he describes as tolerance in modeling nature." The nineteenth-century satire Flatland by Shakespearean scholar Edwin A. Abbott illustrates our limitations. ... 

Basically, Newtonian mechanics worked well for problems involving terrestrial and even celestial bodies, providing rational and quantifiable relationships between mass, velocity, acceleration, and force. However, in the realm of optics and electricity, numerous observations seemed to defy Newtonian laws. Phenomena such as diffraction and interference could only be explained if light had both particle and wave properties. Indeed, particles such as electrons and x-rays appeared to have both discrete energy states and momentum, properties similar to those of light. None of the classical, or Newtonian, laws could account for such behavior, and such inadequacies led scientists to search for new concepts in the consideration of the nature of reahty. 

Scientists in the 1920s, speculating on this problem, became convinced that an entirely new approach was required to treat electrons in atoms and molecules. In 1924 a young French scientist, Louis de Broglie (1892-1987), in his doctoral thesis at the Sorbonne made a revolutionary suggestion. He reasoned that if light could show the behavior of particles (photons) as well as waves, then perhaps an electron, which Bohr had treated as a particle, could behave like a wave. In a few years, de Broglie s postulate was confirmed experimentally. This led to the development of a whole new discipline, first called wave mechanics, more commonly known today as quantum mechanics. 

Controversies still persist in the interpretation of the quantum theory of light and indeed more generally in quantum mechanics itself. This happens notwithstanding the widely held view that all the difficult problems concerning the correct interpretation of quantum mechanics were resolved a long time ago in the famous encounters between Einstein and Bohr. Recent books have been devoted to foundational issues [26] in quantum mechanics, and some seriously question Bohrian orthodoxy [27,28]. There is at least one experiment described in the literature [29] that purports to do what Bohr prohibits demonstrate the simultaneous existence of wave and particle-like properties of light. 

Einstein was cautious about promoting this revolutionary idea. Furthermore, he was absorbed in sorting out another set of revolutionary ideas the general theory of relativity After clearing that up, though, Einstein returned to the problems of light and quantum mechanics and finally accepted the hard-to-accept solution Light has a dual nature—sometimes it acts like a particle, sometimes it acts like a wave. 

Now, we have a problem we have proposed, actually assumed, that light could be described as a wave. Einstein just invoked a particle-like property to explain an experiment. Is light a wave or a particle And, if light is a particle as well as wave, what does that say about a particle Can a particle also be thought of as a wave In particular, is an electron a wave as well as a particle ... 

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