@RafiKhali, have you scanned the Forum to get a sense of all of the different things people use Arduinos for? Perhaps one of those would be suitable for your demo.
Think about your market. What sort of things would grab the attention of your audience? Very simple things are often very effective.
What level of programming experience have you? Don't take on something that is beyond your present abilities.
GO BACK to your original post and delete all the stuff about Quantum computing. It's irrelevant to an Arduino project and I nearly stopped reading before I got past that stuff.
...R