Just read this and tell me what you think.

[FatAndFaithless]

Right, atheists believe there is no life after death, no supernatural being or world and so on.
Their belief is based on the laws of Physics.

Needs a correction right off the bat. Atheists simply do not believe in god. That's it. Plenty of atheists don't know shit about physics, and some believe things that directly flies in the face of established science.

That's because "I don't believe in a god" is all that 'an atheist' is. Nothing else necessarily follows from that.

All information we receive is through our five senses, which is then processed in our brains, which also affects our understanding and thinking.
So we know that our brain is responsible for the way we perceive this world we live in.

With certain substances (for example DMT) our minds can be 'altered' where we now live in a completely new world. This new world does not obey the laws of physics. We meet and interact with other beings. The time we spend in this new world is as life like as any.
My thought is, how can we be so sure this new world is only an illusion and not real? The information we receive in this new world is still being processed by our brains, just as though it is right this moment whilst you are reading this post. The brain is the same, the only difference is the way your process the information you receive.
The time we spend in this new world with an 'altered' mind although relatively short; still exists as you have seen and have been in this place.
If you were living in this new world with the 'altered' mind for longer than a few hours, say few years, would you not believe this new world as your only world?

How do you know right this moment whilst you are reading this post your mind is not 'altered' from a time before you were born on this planet?

The brain naturally produces DMT, at three points, a large amount when you are born and when you die, and a small quantity whilst you are dreaming.
This adds to my point, if you were to take DMT right now, you will be transported to a whole new world, the way you perceive information is now completely different to what has been since you have lived. So.. when you are born DMT can be seen in the brain in large quantities.. and when you die DMT can be seen in the brain in large quantities. Can you see the link?

This sounds like one hell of a philosophy/epistemology question which I am utterly unqualified to answer, so I'll leave it to the philosophical heavyweights on this forum. I just wanted to correct your initial premise because it's a misconception we very often see on here.