# Force Carriers - How do they work?

#### daisey

Hello everyone! I am a new member, and this is my first post.

I am a engineer by training, but I have always enjoyed physics. I have been reading a number of books lately about Quantum Physics, and there are a number of things I still don't understand. But there is one question in particular that I have been wanting to ask a physicist. Imagine my surprise when I stumbled across this web site today at work.

My question concerns the force carriers. In particular, I am referring here to gluons (Strong force), and gravitons (the Gravitational force).

I am having a very hard time understanding how a particle travelling between two points (such as a gluon or a graviton) can transmit a force that has the effect of "pulling" the objects together or closer, as is apparently done by the Strong force and Gravity. It is much easier to understand how a partical that strikes another can "push" it away, but I am having a hard time getting my mind around how a partical can transmit a force that "pulls". Especially at such HUGE distances over which gravity works.

Now I understand that gravity is really just curvature of space, so are gravitons and gluons somehow curving space and therefore causing these forces?

If you can, please try to answer in laymans terms so I can understand. And thanks in advance.

Related Quantum Physics News on Phys.org

#### tiny-tim

Homework Helper
Welcome to PF!

My question concerns the force carriers. In particular, I am referring here to gluons (Strong force), and gravitons (the Gravitational force).

I am having a very hard time understanding how a particle travelling between two points (such as a gluon or a graviton) can transmit a force that has the effect of "pulling" the objects together or closer, as is apparently done by the Strong force and Gravity.

Now I understand that gravity is really just curvature of space, so are gravitons and gluons somehow curving space and therefore causing these forces?
Hello daisey! Welcome to PF!

We had a rather long discussion on these virtual particles recently …

my first contribution started (click on the arrow) …
Hi mmang! Welcome to PF!

The photons are called "virtual particles" … that means they don't exist, except in the maths.

They are a useful mathematical concept which helps to explain perturbation equations in quantum field theory … the annihilation and creation operators of photons are used in the algebraic expansion that approximates the field, but that's all that's meant by "mediated by photons". …
… though other people had other views.

#### Bob_for_short

It is the Coulomb-like force that is mainly responsible for attracting/repulsing, not the "radiated" virtual particles. Some relativistic (v/c) and quantum (h_bar) effects modify slightly the result of Coulomb interaction of De Broglie waves (not point-like particles).

The theory can be formulated in the "Coulomb gauge" where the (strong) Coulomb force 1/|R_1 - R_2| is separated from the (weak) radiated field.

In other words, there is no "shooting" at each other between point-like particles, but there is (mainly) Coulomb-like interaction of De Broglie waves that are present everywhere with respect to each other.

Bob.

#### daisey

Tiny-Tim,

Good to meet you. And thanks for responding.

Regarding that thread - Wow. I apparently need to do more reading. Until I read that thread, I thought I was getting a fairly good understanding of the subject of QM. I guess I was too optimistic to think some of these concepts could be explained in a simplistic way that a non-scientist could understand. That was the first time I've heard of...
• Photons referred to as "Virtual Particles"
• Particles moving backwards in time

But I am not dissauded! It actually wet my appetite to further my research on the subject. I am going to pick up a book on Field Theory to see if I can get a better understanding. Most of the books I have read so far have been overviews of Quantum Mechanics, so most of that thread went way over my head, as did Bob_for_short's response (thanks for trying, though, Bob ).

Take care, Daisey

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