Remember
playing Super Mario Bros. 3 as a kid (okay, maybe as an adult, too) and
encountering Boos? The sneaky ghosts would only move when you weren’t watching
them.
Well,
Cornell physicists verified that, much like the fictional foes from the Mario
universe, a quantum system can’t change while you’re watching it.
Of course,
the real process is a little different, and has more to do with how we are able
(or not able) to measure the world of the very tiny.
A Watched
Pot Never Boils
This effect
was considered one of the strangest predictions of quantum theory, but the
experiments performed in the Utracold Lab of Muknud Vengalattore, associate
professor of physics, confirmed it.
Eventually,
Vengalattore established Cornell’s first program to study the physics of
materials cooled to temperatures as low as .000000001 above absolute zero;
though, Vengalattore wasn’t alone in the study. For the experiment, graduate
students Yogesh Patil and Srivatsan K. Chakram made and cooled a gas of about a
billion Rubidium atoms inside a vacuum chamber and suspended the mass between
laser beams.
Graduate
students Airlia Shaffer, Yogesh Patil and Harry Cheung work in the Ultracold
Lab of Mukund Vengalattore, assistant professor of physics. Credit: Cornell
Chronicle.
This is when
the team observed something exceptional: The atoms wouldn’t move around as long
as they were under observation. The more often the group used a laser to measure
the behavior, the less movement they saw. The only way the atoms would move was
when the researchers turned down the intensity of the laser, or turned it off
completely.
Notably,
otherwise, the atoms organized themselves freely into a lattice pattern, just
as they would if they were crystallizing.
The Future
of Atom Manipulation
It must feel
pretty cool to stop atoms just by looking at them with the lasers, but there
are much larger ramifications for this discovery. For example, it shows that
quantum cryptography should work— meaning an intruder can’t spy on your
communications without destroying the data.
“This gives us an unparalleled tool to control a quantum system, maybe even atom by atom,” said Patil, lead author of the paper. Furthermore, this work opens the door to a fundamentally new method to manipulate the quantum states of atoms and could lead to new kinds of sensors, explains the Cornell Chronicle.
Read more
about how we impact small systems by imaging them in the Oct. 2 issue of the journal Physical Review Letters.
Comments
Post a Comment