1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Incompatibility between Quantum Mechanics and Relativity

  1. Jan 22, 2015 #1


    User Avatar
    Gold Member

    The incompatibility between Quantum Mechanics and Relativity is one of the stumbling blocks in physics

    Is it possible that this problem is related to the phenomenon of emergence? For example, a traffic engineer can treat the movement of a large number of vehicles as the flow of a liquid. But at the level of an individual car this does not work.

    Another example is the behaviour of a flock of starlings, at the individual level it is just a bird but in large numbers they form complex mathematical patterns in the sky

    So similarly, relativity may work when we are looking at very large numbers but break down at the micro level - just like the vehicle and bird analogy

    Nobody would say "how can this thing behave like a car at the micro level but like a liquid at the macro level?" so maybe at the micro level Quantum Mechanics holds sway but at the macro level Relativity holds sway?
  2. jcsd
  3. Jan 22, 2015 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member
    2017 Award

    (Special) Relativity is not incompatible with quantum mechanics. The development of relativistic quantum mechanics and quantum field theory was a cornerstone in the development of the standard model of particle physics, one of the most successful physical theories to date. You should not be surprised to get a non-relativistic QM theory when you take certain limits in relativistic QM, just as you should not be surprised that Newtonian mechanics is only valid as an approximation of SR for low velocities.
  4. Jan 22, 2015 #3
    Question is not precisely clear.As I so far understand QM effects come in to play at subatomic level irrespective of velocities and relativistic effects come in to play at near light speeds irrespective of sizes.
    Do you want to compare single electron through two slits and flow of electrons in Young's double slit experiment and compare the patterns on screen.
    How you are linking relativity?
    Or you are thinking of Boltzmann work of Gas Laws etc.
    Please simplify your question.
    I am not an expert but am serious to understand.
  5. Jan 22, 2015 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    The link below is a lecture from a typical, college course in Relativistic Quantum Mechanics:


    I have no clue on where you get the idea that QM and Special Relativity are not compatible, when it is already well established and even taught in school as a standard course!

    What I suspect is that you are confusing the problem with incorporating gravity, and thus, General Relativity, within the quantum field theory picture, with the misunderstanding that the entire theory of Relativity is incompatible with QM. You need to straighten out your misunderstanding.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook