How to sound proof floors to minimize sound

[Austin Haynes]

I recently just closed on my first investment property it is a up and down duplex! Unfortunately, I can hear when someone is walking around upstairs. The flooring in the upstairs unit is original hardwood and if I can avoid replacing the floors that would be great. I was wondering if anyone in the bigger pockets community could advise me on if there is a type of sound proof mat, carpet etc. that I can buy to lay on top of the hardwood in the living room and the bedrooms in the upstairs unit to minimize the sound. Thank you for any help!