This hot investing theme is unlikely to cool anytime soon.Artificial intelligence (AI) may be the hottest investment theme on the planet right now -- and for good reason. Companies involved in this potentially game-changing technology have led the S&P 500 to a winning performance over the past two years and have propelled the index higher so far this year, too. I'm talking about stocks like Nvidia, Alphabet, and Meta Platforms -- each heading for an annual increase of more than 30%.These players all make gr ...