323 | Jacob Barandes on Indivisible Stochastic Quantum Mechanics

Hello, everyone. Welcome to the Mindscape podcast. I'm your host, Sean Carroll. Quantum mechanics, one of our favorite topics here at Mindscape, continues to be in this weird situation where it's a wonderful theory that fits all the data. We can do spectacularly good calculations, compare them against experiment, achieve agreement to many significant figures, and yet it is very, very easy to ask questions about quantum mechanics that we don't know the answer to, not just what would happen questions, but what does the theory say questions. And so we have the whole sub discipline of foundations of quantum mechanics, trying to figure out what the true theory is behind the successful quantum mechanical predictions. And as many of you know, there are different approaches here. Ordinarily, in quantum mechanics, you have a wave function, and then the first question you ask is, does the wave function represent reality or is it merely epistemic? Is it merely something about our ability to make predictions about things? But then if you do think that the wave function represents reality, then you still have choices. Is it the sole representative of reality, or are there hidden variables or something like that? And if it is the sole representative of reality, does it always obey the famous Schrodinger equation, in which case you get the many worlds theory, Or does it sometimes change stochastically, at different moments depending on what model you have? Then you have objective collapse models of various sorts. And all of these theories are truly different theories. They're not different interpretations of quantum mechanics. They potentially have different experimental consequences. In some cases, we know clearly what those different experimental predictions are. In other cases, we're less sure. But still, we don't have a consensus that one of these approaches is on the right track, and therefore, it's useful, very, very important, in fact, I would say, to develop entirely new alternatives to these famous models of quantum mechanics because who knows? Maybe we just need to be shaken out of our dogmatic slumbers, and then we'll find the right answer. Today's guest, Jacob Barandas, is a physicist and philosopher at Harvard University, and he has a proposal for a brand new way of thinking about quantum mechanics. When I say brand new, it's, you know, brand new is always a questionable thing in science or academia because everyone always has predecessors. So great. Jacob's idea of quantum mechanics lives in a tradition of what is called stochastic models of quantum mechanics. There have been some stochastic models of quantum mechanics, but he has a different one. Okay? So his particular approach is distinct from anything that's been tried before. And I'll tell you the basic idea of it now because, spoiler alert, this podcast is very long. It takes us a while to get to what Jacob is actually proposing in his new theory because we spent a lot of time preparing groundwork for understanding the issues …