Atom laser creates reflective patterns similar to light

Date:
December 10, 2021
Source:
Washington State University
Summary:
Cooled to almost absolute zero, atoms not only move in waves
like light but also can be focused into shapes called caustics,
similar to the reflecting or refracting patterns light makes on
the bottom of a swimming pool or through a curved wine glass. In
experiments, scientists have developed a technique to see these
matter wave caustics by placing attractive or repulsive obstacles
in the path of a cold atom laser. The results are curving cusps or
folds, upward or downward 'V' shapes. These caustics have potential
applications for highly precise measurement or timing devices such
as interferometers and atomic clocks.



FULL STORY ========================================================================== Cooled to almost absolute zero, atoms not only move in waves like
light but also can be focused into shapes called caustics, similar to
the reflecting or refracting patterns light makes on the bottom of a
swimming pool or through a curved wine glass.


==========================================================================
In experiments at Washington State University, scientists have developed
a technique to see these matter wave caustics by placing attractive
or repulsive obstacles in the path of a cold atom laser. The results
are curving cusps or folds, upward or downward "V" shapes, which the researchers describe in a paper for Nature Communications.

While it is foundational research, these caustics have potential
applications for highly precise measurement or timing devices such as interferometers and atomic clocks.

"It's a beautiful demonstration of how we can manipulate matter waves
in a way that is very similar to how one would manipulate light," said
Peter Engels, WSU Yount distinguished professor and the paper's senior
author. "An atom is accelerated by gravity, so therefore, we can mimic
effects that would be very difficult to see with light. Also, since atoms respond to many different things, we can potentially exploit this for new
types of sensors that are particularly good at detecting magnetic fields, gradients in electric fields or in gravity." To achieve these effects,
first the scientists had to create one of the coldest places on Earth,
which they were able to accomplish in the Fundamental Quantum Physics lab
at WSU. Engels and his colleagues used optical lasers to take energy out
of an atomic cloud trapped inside a vacuum chamber, cooling it very close
to absolute zero (?273.15 degrees Celsius or ?459.67 degrees Fahrenheit).

This extreme cold makes atoms behave quantum mechanically in ways very different from the familiar laws of nature. In these conditions, instead
of behaving like particles of matter, the atoms move like waves. Clouds
formed of such atoms are known as Bose-Einstein condensates, named
after the theorists whose work first predicted this state of matter,
Albert Einstein and Satyendra Nath Bose.



==========================================================================
In the process of exploring these condensates, the researchers at WSU
created a cold atom laser, meaning the wave-like atoms started lining
up in a column and moving together.

"A light laser is a collimated, coherent stream of photons, and we're essentially doing that with atoms," said Maren Mossman, the paper's
first author who worked on the project as a WSU post-doctoral fellow
and is now the Clare Boothe Luce assistant professor of physics at the University of San Diego. "The atoms sort of walk together and behave as
one object. So then, we decided to see what happens if we poked this."
For this study, the researchers 'poked' at the atom laser by putting
optical obstacles in its path, essentially shining specific wavelengths
of laser lights onto the accelerating stream of atoms. One obstacle
type repelled the atoms and made caustics in downward fold shapes;
another attracted them making caustics in upward cusp shapes.

The system is also very tunable, the researchers said, meaning they can
change how fast the atoms accelerate.

"Caustics in atom lasers have never really been studied with this
flexibility," said Engels.

In addition to Engels and Mossman, the co-authors include Michael Forbes,
WSU associate professor in the Department of Physics and Astronomy and
Thomas Bersano, a former WSU post-doctoral fellow now at Los Alamos
National Laboratory.

This study was supported by grants from the National Science Foundation.

========================================================================== Story Source: Materials provided by Washington_State_University. Original written by Sara Zaske. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. M. E. Mossman, T. M. Bersano, Michael McNeil Forbes, P. Engels.

Gravitational caustics in an atom laser. Nature Communications,
2021; 12 (1) DOI: 10.1038/s41467-021-27555-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211210093025.htm

--- up 6 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)