The World as a Hologram (arxiv.org)

This is one of the original papers that described the concept of holography, which is a central concept in quantum gravity research. It's a neat paper because although the subject matter is highly technical, the author describes the basic idea largely using undergraduate physics and without a lot of fancy math.

Posting since there was some interest in a related Quanta article here recently https://news.ycombinator.com/item?id=49845998