I have no doubt that chi/ki exists, but most of my experiences are personal, not open to independent verification. On the other hand I can suggest an example that I have always found to be true.
Watch a white belts kata performance, then place them in the middle of two advanced black belts and have them perform the same kata as before. This time the white belt approaches black belt level of performance. This works the same way for everyone, place a green belt between two ni-dans, or a brown belt or a ni-dan between two roku-dans and obtain the same result.
Sure there are several possible contributing factors. The presence of the dans might be providing visual and auditory clues to the kyu performance. But select a kata that they are very experienced with.
There is also less performance pressure for the lower raked student. They feel everyone will be watching the dans and not them.
For myself, I prefer another answer.
I feel the lower ranked student borrows the energy of their senior’s performance.