Professor Dennis Krause says the truth about our universe—particularly at the atomic level of many of today’s important scientific breakthroughs—really is stranger than fiction.
He knows this better than most.
A voracious reader and short story writer, Krause is also a theoretical physicist whose research looks at quantum mechanics, unstable particles, and the search for new dimensions.
Last Friday during a passionate, personal, and inspiring 36th Charles D. LaFollette Lecture in the Humanities, he delivered the wonders of that “fantastic and wonderfully different” quantum world to the doorstep of his fellow professors in theology, philosophy, literature, art, classics, music, and theater.
And for 50 minutes during a presentation that was as much about telling stories as it was about science, those colleagues joined Krause in the very work suggested by his lecture’s title—"Grappling with the Quantum: Trying to Understand the Fundamental Rules Governing Our World."
Pacing the Salter Hall stage with an excitement sparked when he was a Minnesota farm boy reading Isaac Asimov’s description of neutrinos, the first physicist honored with an invitation to present the College’s most prestigious lecture began with what the humanities and science have in common.
“While the painter, photographer, and poet are each trying to capture some aspect of the physical world on canvas, digital media, or paper, I’m trying to capture some element of the universe with mathematical equations,” Krause said. “These are all the result of human minds trying to express thoughts and feelings about our world.
“There is, however, a big difference between what I do and what these artists do. As a professional physicist, I am not free to do whatever I want. Richard Feynman referred to it as ‘imagination in a terrible strait-jacket.’”
For example, Krause said, “When I’m practicing my hobby of short story writing, I’m free to imagine a small town in northern Minnesota where the townspeople must drape the body of a freshly killed victim over an ancient oak tree to ward off an unspeakable horror. But as a physicist, I can’t tell any story I want.
“It doesn’t matter how beautiful and elegant the equations may be, if they fail to describe the world, they must be discarded. In physics, theories must work.”
That doesn’t make physics “cold and impersonal” or “antithetical to the humanities,” Krause insisted. “Nothing can be further from the truth. I do what I do not just because it (hopefully) provides insight about the world—I also do it because it is fun!”
He quoted Nobel laureate physicist Steven Weinberg: “We learn how to do science not by making rules about how to do science, but from the experience of doing science, driven by desire for the pleasure we get when our methods succeed in explaining something… We develop an aesthetic sense that gives us clues to what theories will work, and that adds to our pleasure when they do work. Our understandings accumulate. It is all unplanned and unpredictable, but it leads to reliable knowledge, and gives us joy along the way.”
Introducing Krause’s talk, last year’s LaFollette Lecturer and English Professor Agata Szczeszak-Brewer quoted theoretical physicist Carlo Rovelli and his defense of “the marriage between science and the humanities: Science is about constructing visions of the world…a process in which we keep exploring new ways of thinking and keep changing…our vision of the world, to find new visions that work a little better.”
Krause spent much of his 50 minutes illuminating that vision at the quantum level for his Salter Hall audience.
After a brief primer on classical physics—“the rules governing the objects of our everyday world”—he explained why those same rules had failed to describe an accurate model of the universe at the atomic level.
“Then, in the 1920s, completely new ideas emerged which solved the problem. But not in a way that anyone would have expected. Werner Heisenberg, Louis De Broglie, Erwin Schrödinger, Paul Dirac, Max Born and others needed to develop an entirely new mechanics to explain atoms—quantum mechanics.”
This quantum world is so different, Krause said, “that the best way we have to understand the atomic world viewed through the quantum lens is through mathematics.”
Krause described quantum mechanics as “mathematical rules that provide us with measurement outcomes where results come in discrete quantities.”
“The energies of an atom are ‘quantized’ in the same way that the discrete musical notes of a guitar string or the flute arise.”
Quantum mechanics is also “a theory of probabilities. Unlike classical mechanics, it doesn’t tell us what will happen, but what may happen.”
But it’s not that simple.
“While nearly all physicists agree on the mathematical formalism of quantum mechanics and how to use it, there is no universal interpretation of what is happening or even what the quantum state vector Ψ really means. There are four physicists in the Wabash Physics Department, and it is very likely we all have somewhat different views on the meaning of quantum mechanics.”
And while physicists agree on how to use quantum mechanics to calculate what will be observed in an experiment, they do not agree on the interpretation of what goes on.
That’s because the nature of quantum mechanics does not allow us to tell a complete story, Krause said. Physicists can measure outcomes, but not how they happen. Like the beginning and end of a story with no plot in between, the behavior of particles at the quantum level seems like an amazing machine that disappears every time you look at it. And observer is entangled in and affects the equation.
In a visual highlight of the talk, Krause projected on screen an optical illusion—the Necker Cube—to provide an analogy for the different ways of looking at the single path an atomic particle may take.
“There have been many attempts to explain this weirdness,” Krause said. “Some do this by introducing alternate universes. Others try to envision the atom simultaneously taking both paths simultaneously. In other interpretations, the atom is guided by a mysterious quantum potential which is determined by the experimental configuration.
“My own feeling is that the situation is more complicated than this. The picture of atoms as particles is encouraged by the way they are detected, but all of these quantum systems are probably better described by quantum fields which combine wave and particle aspects. Even then, it is not clear to me that this will allow one to complete the narrative of what is actually going on. “
In an intriguing sequence that underlined the importance of scientific research in liberal arts institutions, Krause described a series of problems and ideas he worked on with students Zach Rohrbach ’12, Inbum Lee ’16 and his own mentor, Purdue University Professor of Physics Ephraim Fischbach, his frequent collaborator in his more than 50 published research papers.
“Nature seems to be preventing us from telling a story of what is happening in the quantum realm,” Krause said. “When information of what is going on leaks out, the very thing we’re trying to understand disappears. The funny thing is that these strange goings on, behind a cloak of secrecy, are vital to our world around us and are becoming part of our everyday technology like LEDs, lasers, and computers.
“We are living in a quantum world, but the machinery (if there even is machinery!) is hidden away.”
During a reception following the talk, international literacy advocate and Wabash Trustee Emeritus Robert Wedgeworth ’59 called Krause’s talk “the finest” he could recall in decades attending these lectures. LaFollette Professor of the Humanities Emeritus Raymond Williams ’68 noted how Krause’s talk of “a mysterious quantum potential” and “nature preventing us from seeing what is happening” brought the talk to the margins of theology. Art Professor Matt Weedman was caught up in a conversation of his own with Krause about the implications of the lecture for his discipline.
Commenting on how much he had enjoyed the lecture, Gary LaFollette said he uncertainty and mystery of the talk reminded him of a quote he’d often heard his father, Charles D. LaFollette, recite—written by Robert Louis Stevenson and sometimes attributed to the Buddha: “It is better to travel hopefully than to arrive.”