The Nielsen transformation, sometimes called the square root of the quantum Fourier transform, is a way of changing the way information is stored and processed in a quantum computer. Imagine you have a bunch of toys in a toy box. Normally, you would take out each toy one by one to play with it. But with the Nielsen transformation, you can take out all the toys at once and play with them in a different way.
The Nielsen transformation is like taking a bunch of different pieces of information, like a bunch of different toys, and combining them into one bigger piece of information, like a big toy that you can play with in a different way. It does this by using a series of operations that work together to change the way the information is stored and processed.
One of the key features of the Nielsen transformation is that it allows you to take advantage of the properties of quantum mechanics, which are different from the properties of classical mechanics. For example, in quantum mechanics, you can have something called a "superposition," where a particle can be in multiple states at the same time. The Nielsen transformation takes advantage of this by allowing you to perform operations on all the possible states at once, instead of one at a time.
Overall, the Nielsen transformation is a powerful tool that can help you process information in new and innovative ways using the principles of quantum mechanics.