This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
equations:klein-gordon_equation [2019/07/30 08:32] 60.52.77.62 [Klein-Gordon Equation] |
equations:klein-gordon_equation [2019/07/30 08:52] 60.52.77.62 [Why is it interesting?] |
||
---|---|---|---|
Line 38: | Line 38: | ||
<tabbox Why is it interesting?> | <tabbox Why is it interesting?> | ||
- | The Klein-Gordon equation is the correct equation of motion that describes free [[basic_notions:spin|spin]] $0$ particles. | + | The Klein-Gordon equation is the correct equation of motion that describes free [[basic_notions:spin|spin]] $0$ particles. For a spin-1 generalization see the Duffin-Kemmer-Petiau equation. |
| | ||
Line 46: | Line 46: | ||
* $\partial _{\mu} $ denotes the partial derivative and $\partial _{\mu} \partial ^{\mu}$ stands for a sum using the Einstein sum convention, i.e. $\partial _{\mu} \partial ^{\mu} = \partial _0 \partial^0 - \partial _1 \partial^1 -\partial _2 \partial^2 -\partial _3 \partial^3$, | * $\partial _{\mu} $ denotes the partial derivative and $\partial _{\mu} \partial ^{\mu}$ stands for a sum using the Einstein sum convention, i.e. $\partial _{\mu} \partial ^{\mu} = \partial _0 \partial^0 - \partial _1 \partial^1 -\partial _2 \partial^2 -\partial _3 \partial^3$, | ||
* $m$ denotes the mass of the particle, | * $m$ denotes the mass of the particle, | ||
- | * $\Phi$ is either the wave function of the spin $0$ particle if we use the Klein-Gordon equation in a particle theory, or describes the spin $0$ field if we work in a field theory. | + | * $\Phi$ describes the spin $0$ field if we work in a field theory. |
+ | * Note: $\Phi$ cannot be interpreted as a wavefunction because it is a real valued field; it is its own anti-particle like the Majorana fermion. Only in the case that it is the U(1)-charged (requires 2 independent real Klein Gordon fields that are symmetry transform into each other) is a naive wavefunction interpretation possible. Basically, you get a relativistic scalar superfluid field. Nevertheless, there are single particle wavefunctions lurking in the single real Klein-Gordon theory. But you need to use the coherent state representation to see the 1st quantized operators from the complex annihilation and creation operators. Essentially undoing the second quantization. | ||