What is Duality of light: Definition and 12 Discussions

Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the behaviour of quantum-scale objects. As Albert Einstein wrote:
It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.
Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles exhibit a wave nature and vice versa. This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. For macroscopic particles, because of their extremely short wavelengths, wave properties usually cannot be detected.Although the use of the wave–particle duality has worked well in physics, the meaning or interpretation has not been satisfactorily resolved; see Interpretations of quantum mechanics.
Bohr regarded the "duality paradox" as a fundamental or metaphysical fact of nature. A given kind of quantum object will exhibit sometimes wave, sometimes particle, character, in respectively different physical settings. He saw such duality as one aspect of the concept of complementarity. Bohr regarded renunciation of the cause-effect relation, or complementarity, of the space-time picture, as essential to the quantum mechanical account.Werner Heisenberg considered the question further. He saw the duality as present for all quantic entities, but not quite in the usual quantum mechanical account considered by Bohr. He saw it in what is called second quantization, which generates an entirely new concept of fields that exist in ordinary space-time, causality still being visualizable. Classical field values (e.g. the electric and magnetic field strengths of Maxwell) are replaced by an entirely new kind of field value, as considered in quantum field theory. Turning the reasoning around, ordinary quantum mechanics can be deduced as a specialized consequence of quantum field theory.

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  1. P

    I Article on photon wave-particle duality

    We all know that Feynman declared wave-particle duality as the central/only problem of quantum physics. Not sure how to evaluate a recent publication summary on this topic: https://sciencex.com/news/2020-11-wave-particle-duality-entanglement-customary-pitfalls.html Would like others take on...
  2. universal2013

    Beginning through the Pedrotti optics book -- I have an energy question

    Hello. I started to work on pedrotti optics book (2nd edition) and i got confused about what is relativistic mass and why we use it rather than kinetic energy (1/2mc^2)? Also in the beginning of these explanations there is one equation i barely understand nothing out of it. Could you please...
  3. cliffhanley203

    Wave / particle duality of light

    Homework Statement I've just read that light can behave like a wave at times, and a particle at other times. How does the light from the Sun traveling towards Earth behave? A wave? A particle? Or both? And is it in any sense something that actually starts at the Sun, travels across space and...
  4. P

    B What exactly are waves and how do they look?

    Now, whenever I asked this question, my teachers either responded with a diagram of a wave like this (psst! it doesn't move in real life, I didn't go to Hogwarts.): or often referred to the analogy of water waves (when you drop something in water, the wave goes outward). But when we talk...
  5. DavidReishi

    I "Light is wave-like and particle-like" --- Why this is wrong?

    It's often said that light has both "wave-like" and "particle-like" properties, that light is both "wave-like" and "particle-like." But such a concept is fundamentally out of sync with reality. For, while it's true that light exhibits "particle-like" properties, the same cannot be said about...
  6. aditya ver.2.0

    The Wave-Particle Duality of light and the laws of reflection

    I wonder how the wave particle duality property of light persists with the laws of reflection? How exactly is a photon directed in the same angle (i.e. the angle of incidence) by a particle as reflection while abiding through the quantum theory and the Raman Effect? Such as we throw an elastic...
  7. D

    What quantity shows the wave particle duality of light?

    What quantity measured in the Compton effect experiment shows the wave- particle duality of light? the momentum shows the wave particle duality of light. is this true? The Compton Effect is An increase in wavelength of X-rays or gamma rays that occurs when they are scattered.
  8. E

    Light Particle & Wave: 4D Space Reality?

    Is there a possibility that light can be a particle and wave at the same time? If so then there is the proof that there exists a physical manifestation of 4D space.
  9. R

    Debating Wave-Particle Duality of Light

    Hi, A friend and I have been having a long standing debate on the nature of light, being an uneducated layman I tend to stick to the conventional interpretation of wave-particle duality but my friend maintains that light is solely a wave. He found this link at [link to crackpot website...
  10. G

    Need simple help with: Duality of Light and Gravity Lenses

    hello members of www.physicsforums.com ! primarily i want to apologize for the double thread post; i posted another thread at this link: https://www.physicsforums.com/showthread.php?p=1950906#post1950906 and i am afraid it was homework and i did not see the homework section so please forgive...
  11. R

    Exploring Wave-Particle Duality of Light: A Theory

    Sometimes light exists in the form of a wave and sometimes light exists in the form of a particle or wave/particle duality. Light existing in two completely different forms does not make sense to me but the experiments have proved this right? I have a theory that light is actually a stream of...
  12. LeonhardEuler

    Exploring Wave-Particle Duality of Light

    I have only taken an introductory course on QM so far, and a lot of it doesn't make sense to me. One thing that confuses me is what light is. In classical physics it was a wave consisting of oscilating electric and magnetic fields. In QM, I keep hearing about "wave-particle duality". My...