I believe it is what we in pool call "the zone". Where one lets go of everything around him. There is no thought of winning, no thought of losing, no thought of making the ball or missing the ball. There is just oneness with the table. The balls become ones entire existence at the time. Pure performance. Task at hand is to make the balls and get shape on the next ball to make it. The subconscious totally takes over and accomplishes the task assigned to it.
I also know that there are different levels of "the zone", and different ways to achieve "the zone". Different levels meaning that at one end of the zone, one is still somewhat aware of what they are doing. At the deepest level, which I have only achieved once in my life, there is not even a memory of what one has just done, there is only the performance. I only know of it from what others have said and by the amount of people that came over to watch what I was doing. I was that deep in the zone for about an hour, and have no recollection at all of anything I did at the time. Yet, at the end of it, when I finally came out of that deep "trance", there were about 50 people standing around the table watching me.
All I knew, was I started out showing someone how to play the game, and just fell into the trance. Afterwards people were wanting my autograph, which was extremely awkward to me. I was just a bar player. Had no idea what they saw and experienced. But, even not knowing what I had done, I knew it had to be very, very, special to attract that kind of attention. And it proved to me that what we normally do is no where's close to what we are actually capable of doing.
At the lower level of the zone, one can achieve it by simply eliminating all judgement. This I have done on command. No worry about winning or losing, no worry about how one looks to others. Just the thought that you will perform your best, and just see where that actually is at the time. Then, just letting it happen. You have that initial thought to tell your subconscious what the end goal is, then let it go and not think about it again. Everything around you goes away, and you just play pool. You allow your subconscious to do what your conscious has trained your body to do in practice.