If there is, would we know about it? My initial scenario was to use it like the E-Meter in Dianetics. My understanding of their usage, is that you are asked a bunch of leading questions while the "auditor" watches the needle on what is basically just a galvanic skin response testor - one piece of a polygraph. Your changes in skin resistance indicate states of conflict or tension. The point is not just to map these conflicts, but to demand that you make a real commitment to do something about them, at which point the needle drops back to normal. When there are no longer any such identifiable zones in your mind, and the needle stays in the normal zone no matter what you're asked, then I believe you are declared "clear."
By itself, this would certainly be a potentially very useful system for many people who need to get their lives straightened out, and I think that a lot of people do in fact benefit from this level of Dianetics. At the same time, the auditor is making decisions, based on training, based on other principles of Dianetics, as to what questions to ask, what conflicts to pursue, etc. This is not a value-free process.
So, if you deliberately emphasized the process by which auditing might also be used to verify commitment to the organization..... Well, then you might end up with a rich, powerful organization that knew it could trust its members.
Of course, there is that little problem that the galvanic skin response is one of the easiest things to condition. I.e., anyone with a simple biofeedback loop, which could be as simple as watching a meter (or listening for cues from an auditor?) can learn to control their galvanic skin response in no time at all. Even the polygraphs operate with a high level of mythology. People think that they are going to work, and so they respond accordingly, which accounts for a large portion of their actual success. There are numerous studies showing that polygraph operators can be easily fooled, and I met someone who claimed to have witnessed a polygraph used fraudulently. He knew the employee was telling the truth and had never stolen anything, but the polygraph guy needed to justify his salary by "catching crooks." The guy who knew he was full of it ended up quiting his job in management over the issue.
However, that doesn't mean that a "real truth machine" as described in Halperin's novel can't happen. We can watch the brain/mind in operation now in real time at a pretty fine level of detail with some of the more sophisticated scanners, and that kind of technology just gets better and cheaper, especially if driven by market demand. So, is the demand out there? Can you say "Al quieda?"