I haven't read the book. If you have, please summarize how QM indicates a panpsychist world.
Everyone seems to be using quantum theory nowadays as the mechanism for their speculations.
Now don't get me wrong, I'm not advocating that people take up a belief in Panpsychism. I'm a firm believer that people should wait for evidence before committing to this theory. The OP simply asked whether atheists can be non-materialists too, please realize that I was only trying to answer this question.
I know that movies such as What The Bleep Do We Know? gave a misrepresenting view of quantum physics, but those kind of movies also inspired quite a few people to look into real QM too, so it's not all bad.
I haven't read the whole book, just the kindle sample. So, I can't tell you the whole theory professor Shan Gao presents, but it
appears to do with Superpositions.
You're obviously familiar with QM but perhaps not everyone is, so I'll summarize what Superpositions are from Wikipedia:
A Quantum Superposition is a fundamental principle of quantum mechanics that holds a physical system—such as an electron—exists partly in all its particular theoretically possible states (or, configuration of its properties) simultaneously; but when measured or observed, it gives a result corresponding to only one of the possible configurations.
This gives rise to the famous Schrodinger's Cat. The cat is both alive and dead until it is observed. Why does observation have such an effect? And does it have anything to do with the nature of consciousness? There are obviously no answers to these questions yet (and anyone who claims they have the answers, is lying) but hopefully there will be some day. I'm not yet ready to rule out Panpsychism.