What is Quantum fields: Definition and 58 Discussions

In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and in condensed matter physics to construct models of quasiparticles.
QFT treats particles as excited states (also called quanta) of their underlying quantum fields, which are more fundamental than the particles. Interactions between particles are described by interaction terms in the Lagrangian involving their corresponding quantum fields. Each interaction can be visually represented by Feynman diagrams according to perturbation theory in quantum mechanics.

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  1. J

    Weinberg's Theory of Quantum Fields

    fantastic books but I find the problems out of my reach. Is there a website that gives the solutions? Thanks.
  2. pellman

    Quantum fields are the basic constituents?

    Occasionally I come across statements to the effect that quantum field theory has replaced particles as the basic consituent of matter with continuous fields. Is this right? From what I understand, a quantum field is an operator field. Which is to say--I would think--that by itself it is...
  3. C

    Exploring Energy Extraction from Quantum Fields and Dark Energy

    1) Assuming that one day physicists will be able to extract energy from the Quantum field, would this energy extraction deplete the field in accordance with conservation of energy laws? 2) If one accepts the notion of the Multiverse, are separate Universes therein sharing a common Quantum...
  4. K

    Classical fields and quantum fields

    We describe classical fields with electromagnetic WAVES. Why can quantum theory describe the electromagnetic field with harmonic oscillations? An electromagnetic wave has a certain direction where it moves with a certain velocity. And an oscillation just oscillates up and down. So, what are the...
  5. E

    Quantum Fields as having infinite degrees of freedom?

    The theory of quantum fields is very strange, indeed, I must admit. Usually in books they introduce a quantum field from the standpoint of a vibrating string in one dimension. Along the string are discrete points or masses that when one of which are disturbed a disturbance is created along the...
  6. M

    Can the Uncertainty Principle be Explained by Time and Space Invariance?

    I just had a thought... If the universe supercools before particles form, then there is a potential for particles to form. But this would be in random locations. And this sounds like a quantum field. Does this sound right, quantum fields are created by supercooling of what "spacetime itself"...
  7. K

    Exploring Quantum Field Forces: Coulomb Charges and Their Constants"

    If the classical attraction between two coulomb charges was constant x q1 x q2 / r ^3 or another constant x q1 x q2/ r^4 instead of k x q1 x q2 / r ^2 (perhaps the constants could still be the same-though I doubt it) what would be the force relations on a quantum scale using coupling...
  8. S

    Workshop on Weinberg's Theory of Quantum Fields

    Workshop on Weinberg's Quantum Theory of Fields Hi, I've just joined this forum. I've been reading Weinberg's Quantum Theory of Fields Vol I for a few years on and off, and I'm now on Chapter 10. While I found it to be the most enlightening approach to Quantum Field Theory, I found parts of it...
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