Can you use carpet tiles to soundproof apartment walls?

They would help because carpet absorbs high-frequency sound waves (like human voices).

Yes, carpet of any kind will help soundproof a room. The difference is amazing. Best of luck to you.

That's a good idea! Curtains help too or large acoustic tiles covered with fabrics (like the panels in a movie theatre).

Be careful, if you use a really good glue or a heavy duty staple gun it will damage the Sheetrock and the landlord will bill you for the repairs and it will be expensive.

Take care in that the glue might eventually be difficult to get off the wall and could lose you your security deposit and more.

You might consider attaching a weighty tarp to a 1” x4” x8’. board, hanging that on the wall with a couple of stud-placed screws or nails, and gluing the squares to that instead.

I dont mean to be a downer, but as a landlord myself, having removed 30 pounds of wallpaper and rescuing those walls, I’ve no idea how difficult it would be do get carpet glue off wallboard or plaster.

Anyway, experiment to see if they would hold to the tarp

i do love the idea. On thought, I think I’d encourage my tenant to buy absolute clearance removable wallpaper and tape over that

It would help. Before you do anything make sure you get permission from the landlord in writing. You don't want to lose any or all of your security deposit. Also read your lease well on what you can do and not do. I also am a landlord and have taken former tenants to court for damages and unapproved modifications.