I am a writer working on a fantasy story set in the modern day.

In the story a scientist finds her way to the realm of the dead - not heaven or hell, a real place where all the dead are sent, indiscriminately. This realm is a place that exists "behind" our world, sort of on another plane of existence. I don't want the scientist to access it by using a special machine or portal as this is a total clich?(C). I was hoping for her to access it through inducing a different state, of mind or body. Ideas I have had include her stimulating the brain in a certain way, inducing a certain emotion, altering body chemistry in some way or something molecular (you can see I'm quite the scientific expert, eh? ) Perhaps there is something that "leaves" the body first when we die or an unexplained spike in certain activity that I could exploit?

What kind of scientist would make this kind of discovery? Which scientific disciplines and job titles could I use to describe the above ideas?

If you believe Dan Brown's book, The Lost Symbol, a Noetic scientist would be just what you're looking for. I have a feeling that it's a lot more quackery than science though.

Good luck! Your book sounds pretty interesting.