# Would forces act with the same symmetry in 4D as it does in 3D?

1. Nov 20, 2005

### Gold Barz

Would forces act with the same symmetry in 4D as it does in 3D?

2. Nov 21, 2005

### .:JimmY:.

well, if we are talking about fourth spatial dimension then i believe forces still 'll be acting with symmetry. But not the same symmetry as in 3-D.

3. Nov 21, 2005

### QMrocks

Let me give you a concrete example of a form of highest symmetry ie, a unit radius 'sphere' in n dimensional space. As usual, it is describe by (x1)^2 + (x2)^2 + (x3)^2 + (x4)^2 +(x5)^2 +.... (xn)^2 = 1. Now start with a vector V=(1,0,0,...). Construct any unitary matrix U and act on that V. Now, you had just bring this vector to another point on that 'sphere'. Now, why can't we have a centripetal force.

4. Nov 21, 2005

### Gold Barz

I dont understand that at all lol (I am just a begginer in physics), is that a yes or a no?

5. Nov 21, 2005

### ZapperZ

Staff Emeritus
Then may I suggest that you first understand simple, basic physics, before you dive into "symmetry in 4D"? It is fine and dandy to be curious, but when you are not equipped to realize the problem AND to understand the answers given, aren't you just going to waste a whole lot of time (and the time of those responding) reading things you have very little clue on?

Zz.

6. Nov 21, 2005

### Gold Barz

You have a point but I was just asking for the answer in laymens terms.

7. Nov 21, 2005

### ZapperZ

Staff Emeritus
No you did not.

Besides, have you tried explaining quantum mechanics to a 2-year old? At some point, you have to be REASONABLE in your questions based on your state of knowledge. If not, people who provide you with the answers will ALWAYS have to backpeddle and have to explain their explanation. This can be quite exasperating.

Zz.

8. Nov 21, 2005

### QMrocks

i doubt your question can be tackled using layman understanding, because layman knowledge should only be limited to 3D.

If you want to understand force/dynamics in 4-dimension and its symmetry, you have to just analyse the form of the differential equation. Read something about Lie Groups and Symmetry, it should help...

9. Nov 22, 2005

### Gold Barz

I dont mean to be a wiseguy and I am not trying to be but isnt this the forum where you get help from people who are more knowledgable than you about physics?

10. Nov 22, 2005

### ZapperZ

Staff Emeritus
But you're asking questions in which (i) you're not even aware of the issue involved in that question and (ii) you are not equipped to deal with the answer. A 2-year old will ask things that he/she are dealing with or familiar with. That 2-year old is not equipped to be able to understand what QM is or what is the signifiance of a "non-commuting operator". You are neither equipped nor familiar with the concept of "symmetry" or "4D". If you ask about QED or QCD, you will be met with the same thing.

There are PLENTY of things you should learn and be curious about that you CAN comprehend. Build up the FOUNDATION to be able to understand the property of higher dimensional space. There are no short cuts! I've seen you post a series of questions related to 4D spaces. Did you think you actually understood all those responses? What did you gain? Was it worth the effort and time to get answers that you soon will forget? So what did you learn out of all that?

You learn NOTHING if it isn't based on what you already know and understand. We learn and understand things when it is built on top of existing understanding. That's why physics is taught in sequence, and the subject matter gets more complex and one understands more. Being TOLD about things that appears out of nowhere is not how one learns. This is what you wish to do.

Zz.

11. Nov 22, 2005

### QMrocks

Trueness. 'Be patient' thats what my QM teacher always say. :tongue:

12. Nov 22, 2005

### shaner-baner

Richard Feynman, the late Nobel Laureate in physics, was once asked by a Caltech faculty member to explain why spin one-half particles obey Fermi Dirac statistics. Rising to the challenge, he said, "I'll prepare a freshman lecture on it." But a few days later he told the faculty member, "You know, I couldn't do it. I couldn't reduce it to the freshman level. That means we really don't understand it."

13. Nov 22, 2005

### QMrocks

And if Feynman could not reduce it, not many in this world can do it then. :tongue: But what you said is right. True understanding entails the ability to reduce the problem to something simple. My QM lecturer did just that. He reduce QM formalisms to just a pair of non-commuting unitary operators who are discrete fourier transform of one another and only employs freshman maths. But he still takes three semesters with over 600 pgs of notes to cover the fundamental QM syllabus. Good thing is that freshman got all the time in the world to study them.. So, simplicity in concepts does not always translate to efficient in time for students to learn. It still takes hella of time.. And as a student of physics, i can totally relate to one who gets impatient. i'm one of them too :tongue2: