Spend some time in Aspen and you may well encounter the Aspen Center for Physics, nestled up against the Klein Music Tent and the Aspen Institute. In fact, I hope you’ll visit the center and attend some of its public lectures — events delivered by passionate experts from around the globe who’ll take you by the hand and share their joy as they guide you to the very edge of humankind’s understanding of the workings of the natural world. But what I want to do in these few lines is take you on a different guided tour and offer you a glimpse of what it’s really like to be one of the 500 or so theoretical physicists who spend a handful of weeks at the center in any given summer.
What is it that we actually do when we’re in Aspen? Why is it so invigorating to us as individuals who already have physics swirling through our thoughts and dreams all year round (even when we’re putting our children to bed or phoning our parents, I’ll confess)? Let’s begin a typical day. We’re walking or biking (or taking the shuttle bus) from our lodgings to the physics center, uplifted by the beautiful mountain views but also seeing — in our mind’s eye — galaxies and black holes or quarks and gluons at play in the universe. At the forefront of our minds there’s a tantalizing, inchoate picture that we’ve been grasping for, perhaps for some weeks — like a potter at the wheel beginning to shape their clay.
Perhaps we’re thinking about a liquid so cold that its atoms are acting like a single giant quantum-mechanical molecule. We’re imagining rotating the liquid’s container and changing the container’s shape all at the same time. What happens? Does the fluid flow, remain still or warm up? Could this be tried in the laboratory? Might something like this already be happening inside stars? Are there uses, say as a space gyroscope? Now we’re at the center, pen or tablet stylus in hand, with a jolt of espresso, a fresh pad of paper and our embryonic story: Can we grab hold of it, pin it down and fashion the lump of clay into a graceful vase? Or will it morph into a plain old bowl or, worse still, slip away as we gradually realize there wasn’t anything worth pursuing there? Often, we’ll grab a colleague, playfully prodding one another at the blackboard, spurring one another to find a promising path.
You may be saying to yourself: This is physics. You’re a physicist. You know the equations.
Get on with it. Just solve ’em? But real physics research isn’t like that. First, you need to craft the right question.
For example: What would happen if I tried to bounce an electron off a superconductor? Crafting the question is just as much a part of the process as answering it. There’s no committee of wise elders out there, augustly handing down questions like homework. So, we struggle to develop a worthy question, drawing on our creativity and knowledge of what’s been done before, hoping we’ll arrive at a story that’s rich and illuminating enough to be worthwhile, but still manageable and new.
And then we struggle to answer it. But what does answering it mean? For many of us, the next step is akin to storyboarding, like for the movies — another board, another step in the story. Here’s where we draw on a blend of physical intuition and familiarity with the story’s characters to sketch out the sequence of ideas that, if fleshed out, should carry us from question to understanding.
Here’s where a hidden skill comes in: the art of making what we call “back of the envelope” estimates. To be interesting, roughly how cold would the liquid need to be? Roughly how fast would it need to rotate? Roughly how large a sample would it be good to have to do something we hope for? Estimates like these rarely call for mathematics any fancier than simple algebra, but they do require familiarity with the landscape. Try asking yourself how many bricks there are in the Wheeler Opera House or, as Enrico Fermi famously asked, “How many piano tuners are there in the city of Chicago?” It’s only after we’ve sensed that there’s a worthwhile story to tell that we bring in the heavy machinery, the powerful mathematical equations of theoretical physics.
And even then, to find our way we typically have to simplify them. But ultimately the aim of theoretical physics is to develop not just mathematical formulas but also robust understanding, so that if the question is tweaked, we have a sense of how the answer would change. Think of a bicycle: Make its wheels a bit bigger and you still understand how it works.
What is it about Aspen and the physics center that adds so much to our way of seeking progress? For me, it’s that all options are on the table. I can choose to focus quietly, uninterrupted by faculty meetings or conference talks. I can choose to air nascent ideas or seek technical help on a hike or over lunch under the trees with a group of colleagues who can get up to speed in seconds and provide expert feedback in real time.
And we can come back a few days later, after chewing on the ideas and letting them percolate in our minds. In fact, on any one day I can choose all of the above — no advance planning needed. All this makes the Aspen experience enormously invigorating, inspiring and productive.
By now, you may well be asking: But where’s the joy? For many of us, it lies in the psychological rush of having new thoughts, of finding new understanding and of your mind’s eye turning to vistas that you haven’t seen before (and, when things go well, no one else has, either). Only the few — such as Newton, Einstein and Heisenberg — have seen new oceans. But even to see a new pond every now and then brings joy and satisfaction as well as starting points for the next explorations.
As history has repeatedly taught us, this kind of exploration, driven by human curiosity and creativity, brings us all valuable, new capabilities for harnessing the natural world, ideally for the good of humankind. Think of the latest iPhone. On board it has some 19 billion transistors, brought to you by the physicists who a century ago dreamed up quantum mechanics and in 1947 realized the world’s first ever transistor, thus launching the silicon revolution.
Now you’re possibly reading this on your cellphone or laptop!.
