- #1

- 7

- 0

What else aside from position, momentum that have NO definite

properties before measurement. Is it only position and momentum?

- Thread starter daezy
- Start date

- #1

- 7

- 0

What else aside from position, momentum that have NO definite

properties before measurement. Is it only position and momentum?

- #2

Fredrik

Staff Emeritus

Science Advisor

Gold Member

- 10,851

- 413

The first quantities you mention are the type of numbers that define a particle species. If you change one of those numbers, we'd be dealing with a different type of particle. Every other quantity is of the "doesn't have a definite value before measurement" kind.

In the non-relativistic theory of a single spin-0 particle, every observable is a function of x and p (the expressions that define them may include other numbers, but no other operators), e.g. energy ([itex]\vec p\,^2/2m[/itex]) and angular momentum ([itex]\vec x\cdot\vec p[/itex]).

In the non-relativistic theory of a single spin-0 particle, every observable is a function of x and p (the expressions that define them may include other numbers, but no other operators), e.g. energy ([itex]\vec p\,^2/2m[/itex]) and angular momentum ([itex]\vec x\cdot\vec p[/itex]).

Last edited:

- #3

tom.stoer

Science Advisor

- 5,766

- 162

In QCD we have a "g" in the Lagrangian which is NOT a charge but a coupling constant. That shows that the e in QED is not a charge either, that it is again a coupling constant, and that this coupling constant is by no means constant as it is affected by renormalization.

In QCD we do not have one charge, but we have an SU(3) color-charge algebra with 8 charges Q

The algebra of charges Q

- Replies
- 120

- Views
- 6K

- Last Post

- Replies
- 24

- Views
- 11K

- Replies
- 138

- Views
- 7K

- Replies
- 17

- Views
- 2K

- Replies
- 2

- Views
- 724

- Replies
- 18

- Views
- 4K

- Replies
- 10

- Views
- 2K

- Replies
- 2

- Views
- 1K

- Replies
- 2

- Views
- 1K

- Last Post

- Replies
- 2

- Views
- 832