Department of Physics Welcomes New Eminent Scholar
The Ohio Eminent Scholar program entices outstanding researchers to set up shop in Ohio for a variety of reasons: the title, the prestige, the lab space. For Chris Hammel, Ohio Eminent Scholar in Experimental Physics at Ohio State, it's the students.
The students?
"I get
so much energy from teaching and from the students," Hammel said. "It's fun to
have this opportunity. I love the attitude and atmosphere at Ohio State."
Hammel
was a second-generation physicist at Los Alamos National Lab. His father worked
there also.
"Typically,
Los Alamos was a much different place [than Ohio State]," Hammel said. "It was
filled with physicists and analytical thinking. I think creativity can be more
important. I loved working with postdocs who came to Los Alamos. They were
always full of energy, so interested in learning, so willing to do whatever it
took."
Hammel's
current research includes the cutting-edge areas of high-temperature
superconductivity and ultra low-temperature physics. He worked with Bob
Richardson, who won the Nobel Prize in 1996, at Cornell University. "He worked
at temperatures below 1 milli-Kelvin." Hammel said. "In other words, really,
really cold."
It took
almost five years to build the experiment, and Richardson spent his career
making it work.
"Now,
you can buy dilution refrigerators that cool to 2 milli-Kelvin," Hammel said.
"These
were great experiments, but I always wanted to make a difference in the world."
When
high-temperature superconductivity was discovered, Hammel worked hard to
understand how it came about. These materials conduct without dissipation at
much higher temperatures, so they could make superconducting applications much
more affordable and readily usable.
"I think
we will see great savings in energy transmission and storage using these
materials, and it's possible to envision transportation using these systems at
higher temperatures," he said. "It has always been a dream to operate
high-speed, energy-efficient superconducting trains."
Hammel
is presently focusing on developing scanning magnetic resonance microscopy as a
way to better measure sub-surface properties of many materials, including
silicon and magnetic materials. The process utilizes nuclear or electronic
spins as a probe of a local environment.
"MRI
uses this same technique," he explained. "The nuclear moments at different
locations in your body produce a unique signal that gives us an image from
inside your body. We want to push this technique to get much finer imagesĀ--possibly
on the atomic scale. We have good high resolution tools for studying surfaces;
we don't have good tools to look at buried features."
This
could have a big benefit in medical situations. Hammel's research is focused on
using the spin of the electron to enhance electronic communication and
computation. Presently, electronics relies exclusively on electronic charge; by
exploiting the spin of the electron, information processing electronics could
be improved.
"Until
recently, spin was ignored," Hammel said. "Information stored using charge is
lost immediately when you turn off your computer. But we know that ferromagnets
maintain their information. If we could incorporate ferromagnetism into the
information processing elements, this could lead to computers that don't need
to be booted."
Instead
of a hard drive, billions of magnets (ferromagnets) would be incorporated into
the logic elements of the central processing unit (CPU).
Carrying
this idea to its limit suggests using an individual spin as the information
processing unit--the bit in a computer. This is the basis for one approach to
quantum computing.
"This
will be very challenging, of course," Hammel said. "This quantum information
processing requires us to overcome many barriers. The cool part is that if it
works, we could perform computations that cannot be conceived with conventional
computers. The difficulty is that it's a really fragile state and difficult to
protect and manipulate."
The
immediate goal is to detect an individual electron spin at ultra low
temperatures in very pure silicon.
"Detecting
a single spin would be like finding the Holy Grail," Hammel said.
He is in
the process of setting up his lab, hiring students and learning more about Ohio
State. Students may find they get as much energy from Hammel as he claims to
get from them.
