# I Size of an electron and Planck Volume.

1. Jun 13, 2017

### Arman777

Theres something that bothers me, We claim that electron is a point particle.From that,
Can we assume the volume the electron is $(l_{h})^3$ ( where $l_h$ is planck lenght ) ?

We know that every information can be described in bits like volume is $(l_{h})^3$ so, In every bit of volume theres one information or electron, or electrons size must be larger then that (still point like) but much more larger then$(l_{h})^3$ ?

Thanks

Last edited: Jun 13, 2017
2. Jun 13, 2017

### Orodruin

Staff Emeritus
No. If you are thinking of an electron as a small ball (or even a single point, or anything like a classical particle) you are doing something wrong. This is not what anelectron is.

I think you have misunderstood the concept of point-like. It means it has no volume.

3. Jun 13, 2017

### Orodruin

Staff Emeritus
Also, Planck's constant has the wrong dimensions, $h^3$ is not a volume.

4. Jun 13, 2017

### Arman777

Well you are right about that.
If it has no volume then how it has a mass ? I can understand it must be very small, also I read in some references that it has zero volume.But at least it must be some dimension ? So Whats electron ? Just a kind of wavefunction ? or something like that.Lets suppose a mole of Hydrogen gas, we can calculate mole of electron which its countable , Isnt that make electron not maybe realistically ,theoritically or maybe even other perspective but as a particle ?
Yeah I noticed that now, I should mentioned it was planck lenght and use different symbol

5. Jun 13, 2017

### Orodruin

Staff Emeritus
Why do you think this is an issue? Mass (or equivalently, rest energy) is an intrinsic property of an elementary

Why? An electron is what we call something that is well described as the excitation of a quantum field. This has some properties that we would also assign to classical particles - hence the name - but it does not mean you can just extrapolate all properties of a classical particle and apply them to the electron.

I cannot extract any coherent meaning from these sentences.

6. Jun 13, 2017

### Arman777

I understand thanks , just I was thinking since the planck volume is the smallest sensable volume and electron is a particle and small (point like etc.) hence we can treat its volume as $(l_{h})^3$ but I was wrong.

7. Jun 13, 2017

### vanhees71

The whole thread starts with a wrong assumption in saying "We claim that electron is a point particle." Who is we? At least it's not me. The best theory we have for elementary particles is the Standard Model of elementary particles, which implies that the best descriptions of electrons is in terms of a quantized Dirac field paticipating in the electroweak interaction (because it's a lepton). No particle physicist in fact claims that the electron is a point particle in a classical sense.

8. Jun 13, 2017

### Arman777

I dont know what this means, So We cant say electron is a point-like particle hence what could we say from the description that you gave ?

9. Jun 13, 2017

### Staff: Mentor

We don't know if that's true. It's a common speculation in quantum gravity, but we don't have a good theory of quantum gravity.

10. Jun 13, 2017

### Arman777

We dont yes, but still can I suppose it cannot be smaller then that ? like Josh wrote an article and he claimed that electron volume cannot be smaller then $(l_h)^3$ and then conclude somethhing from that argument is this considered wrong argument ?

11. Jun 13, 2017

### Arman777

Like in information theory or etc or any other places I heard that every planck volume can be considered " a bit of information" , (one of the Susskind's videos )

I find this ;
Proponents of digital physics claim that such continuous symmetries are only convenient (and very good) approximations of a discrete reality. For example, the reasoning leading to systems of natural units and the conclusion that the Planck length is a minimum meaningful unit of distance suggests that at some level, space itself is quantized
John A. Wheeler, 1990, "Information, physics, quantum: The search for links" in W. Zurek (ed.) Complexity, Entropy, and the Physics of Information. Redwood City, CA: Addison-Wesley.
From Wikipedia

12. Jun 13, 2017

### Staff: Mentor

The objection to supposing that the electron has a volume is that it's not the kind of thing that has a volume to begin with. It has nothing to do with whether or not the volume you suppose it to have is smaller than the Planck volume or not.

The objection to supposing that the Planck volume is the smallest meaningful volume is that it's just a speculation; we don't know if it's true.

Who is Josh and what article are you talking about? If it was not a textbook or peer-reviewed paper it's not a valid source here. You should not be trying to learn science from pop science sources.

This is just a description of the speculations in quantum gravity I was talking about. That's all they are: speculations.

13. Jun 13, 2017

### Arman777

John was an example he is nobody.I understand thanks