Physicist Robert B. Hallock Wins Top Physics Award
Content
Robert B. Hallock, Distinguished Professor Emeritus of physics at UMass Amherst in working with superfluid and solid helium, was recently awarded the top international honor in low-temperature physics: the Fritz London Memorial Prize.
In order to change from its gaseous state, helium needs to be cooled to less that -452° Fahrenheit. Hallock, who received his BS from UMass Amherst in 1965 and taught at his alma mater from 1970 until his retirement in 2020, was recognized by the prize committee for his “many innovative achievements in the physics of liquid helium films and his pioneering work on supertransport in solid helium-4, which includes the paradigm-changing discovery of giant isochoric compressibility.”
“I grew up as a curious kid,” says Hallock, “and the curiosity has never gone away. I’ve always loved asking questions of nature, and then inventing the ways to seek by experimentation and then to understand the answers.”
Helium, it turns out, is just as curious as Hallock. On Earth, it’s nearly always a gas, and it only turns to liquid at -452° F. “But go just a little bit colder,” says Hallock, “down to about -456° F, and something quite remarkable happens.”
It’s commonly known that water phase changes from a gas to liquid to solid as it cools, as does most matter, but helium is extraordinary. It has a fourth phase—neither gas nor liquid nor solid, but a phase known as the “superfluid state,” which has remarkable properties. And it doesn’t really want to become solid, either. To force it into a solid state, not only does it have to be supercooled, but it also has to be subjected to extremely high pressure.
“I’ve spent a good bit of my career exploring the mysteries of helium’s superfluid state and more recently trying to understand what happens when helium becomes a solid,” says Hallock. For instance, he and his student discovered that if you create solid helium, say in a copper box, it is possible to pass helium atoms through the solid and, in the process, the solid will gain density. “Solid helium supports supertransport and is compressible,” he says. “That was a totally unexpected discovery.”
But to make that discovery, Hallock had to first invent the device—the somewhat complicated “copper box,” which, in actuality, is a solid helium experimental cell.
“Bob Hallock is the rare faculty member who excels in all areas of academia—an insightful and curious scholar, a dedicated and committed educator, and a thoughtful and supportive academic leader,” says Michael Fox, dean of the College of Natural Sciences at UMass Amherst. “It is wonderful to see that his talents and impactful discoveries are being recognized with one of the most prestigious international awards in physics. In the College of Natural Sciences, we are truly honored to call Hallock a colleague and are proud of his amazing achievements.”
“I was very lucky to spend my career at UMass Amherst,” says Hallock. “Unless you have interesting, smart, and creative colleagues with whom to bat ideas around, you aren’t likely to get very far. We have a great sense of community.”
But it’s not just the colleagues. “One does not walk a path like this alone,” Hallock continues. “My students and postdocs were with me every step of the way.” “And,” he adds, “my very understanding family and especially my tolerant spouse, Norma, have always been supportive.”
Not only did they help Hallock with his inventions and discoveries, they gave him other gifts that have marked his life. “My very first graduate student loved music and asked if he could bring his record player and collection into the lab—he transformed my understanding of and appreciation for music.”
And then there was the photographer who introduced Hallock to the beauty of the large-format camera. “Photography has changed my life, and that student left me with a lifelong gift.” Indeed, Hallock is a passionate amateur who has shown his photos at shows throughout the Pioneer Valley.
Hallock has served as head of the Department of Physics and Astronomy, and interim dean of the College of Natural Sciences. He is a Fellow of the American Physical Society and has held AFOSR-NRC, A. P. Sloan, and Distinguished University Faculty Fellowships. In 1992 he was designated as a J.S. Guggenheim Fellow and in the same year was awarded the Chancellor’s Medal for Research at UMass Amherst. In 1998 he was designated a University Distinguished Teacher of the Year. He was awarded the Distinguished Faculty Award by the UMass Alumni Association in 2008.
“Hallock’s outstanding science, his collaborative nature and his contagious enthusiasm have been a foundation of our longstanding high profile in research on quantum fluids and solids,” says Anthony Dinsmore, professor and department head of physics at UMass Amherst. “He is a great teacher and an exceptionally supportive colleague.”
Behind a lifetime of achievement, whether in the lab, classroom or behind a camera, lies unquenched curiosity: “for me, it’s all about the excitement of asking questions, searching for answers and the thrill of discovery,” he says.
This story was originally published by the UMass News Office.