Physicists and mathematicians have at times toyed with the idea — trying to figure out whether it is allowable at all under current scientific theories, or what changes would have to be made for it to be allowable. The results to my knowledge have never even been remotely encouraging. Even the "positive" results (possible situations in which it might be allowable) require the postulation of physically unrealistic things, like infinite cylinders.

That being said, the US government has at times put money into fringe theories before, including ESP, remote sensing, mind control, anti-gravity, and faster-than-light travel. It's not impossible that they gave a little money to someone who was thinking about these topics, as a way of hedging their bets. But I've never heard anything credible about a "serious investment" in this topic, and I doubt it ever occurred.