Spectral gap

Okay kiddo, imagine you have a bunch of toy cars with different colors. You want to find out how different these cars are by comparing their colors.

Now, let's say you use a special tool to measure the colors of each car, and you get a bunch of numbers. These numbers tell you how different the colors of the cars are.

The difference between the highest and lowest numbers is called the "spectral gap". It's like measuring the difference between the most different cars and the least different cars.

In science and math, we use spectral gap to measure how much energy it takes for something to change. The bigger the spectral gap, the harder it is for something to change.

So, if the cars were particles and the colors were their properties, measuring the spectral gap would help us understand how much energy it takes to change those properties.