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Researchers shed new light on the atomic "wave function"



  The JQI researchers shed new light on the atomic wave function
The team uses laser light and optics to construct an image of atomic wave function (shown in purple). The graph is an artistic description of this microscopic process, trained on atoms (spheres) hung in an optical grid (high white waves). The team's technique reveals information about an atomic wave function with unprecedented details. Yours sincerely: E. Edwards / Joint Quantum Institute
Physicists have demonstrated a new way of obtaining the essential details that describe an isolated quantum system, such as atom gas, by direct observation. The new method gives information about the probability of finding atoms at certain locations in the system with unprecedented spatial resolution. With this technique, scientists can get details on a scale of dozens of nanometers – less than the width of the virus.


Experiments conducted at the Joint Quantum Institute (JQI), a research partnership between the National Institute of Standards and Technology (NIST) and the University of Maryland, use an optical grid – a network of laser light that stops thousands of atoms – the probability of an atom being in a given location. Since each individual atom in the grid behaves like all the others, the measurement of the entire group of atoms reveals the probability that a single atom will be at a certain point in space

Physical Review X The JQI technique (and similar technique , published simultaneously by a group of the University of Chicago) may lead to the probability that the atomic sites are well below the wavelength of light used to illuminate the atoms – 50 times better than

"This is a demonstration of our ability to observe cable-stayed mechanics, "said Trey Porto from JQI, one of the physicists behind the research. "This is not done with atoms that are close to this precision."

To understand the quantum system, physicists often talk about its "wave function." This is not just an important detail; that's the whole story. It contains all the information you need to describe the system.

"This is the description of the system," said JQI physicist Steve Rollston, another author of the report. "If you have information about the wave function, you can calculate everything else for it – such as the magnetism of the object, its conductivity, and the likelihood of you radiating or absorbing light." While the wave function is a mathematical expression rather than a physical object, the team's method can reveal the behavior that describes the wave function: the probability that the quantum system will behave in a way to another. In the world of quantum mechanics, the probability is everything.

Among the many strange principles of quantum mechanics is the idea that before we measure their positions, objects may not have a specific place. The electrons surrounding the nucleus of the atom, for example, do not travel in ordinary planetary orbits, contrary to the image of some of us in school. Instead, they act like waves, so the electron itself can not be said to have a specific location. On the contrary, electrons reside in fuzzy areas of space.

All objects can have such wavy behavior, but for anything big enough to see the unarmed eyes, the effect is inconspicuous and the rules of classical physics are in place. Notice buildings, buckets or breadcrumbs that spread like waves. But isolate a small object as an atom and the situation is different because the atom exists in the sphere of magnitude where the influence of quantum mechanics is supreme. It is not possible to say for sure where it is, but it will be found somewhere. The wave function provides a set of probabilities that the atom will be found in any given location. the first principles without having to respect it. Very interesting systems, however, are complex.

"There are quantum systems that can not be calculated because they are too difficult," said Rollston, as molecules made by several large atoms. "This approach can help us understand these situations."

Since the wave function only describes a set of probabilities, how do physicists get a full picture of its effects in a short order? The team approach involves measuring a large number of identical quantum systems simultaneously and combining the results into a single picture. This is like moving 100,000 pairs of dice at the same time – each roller gives one result, and contributes one point to the probability curve showing the values ​​of all the dice. Approximately 100,000 atoms of the yterbium optical grid are suspended in their lasers. The Iterbium atoms are isolated from their neighbors and are confined to moving back and forth along a one-dimensional line. To get a high-resolution picture, the team found a way to monitor the narrow cuts of these segments, and how often each atom appears in the appropriate part. After observing a region, the team has measured another until it has received the whole picture. has directly seen something central to the quantum research that fascinates him.

"It's not quite obvious where it will be used, but it's a new technique that offers new opportunities," he said. "We've been using an optical grid to capture atoms for years, and now it's becoming a new kind of measuring tool."
Extremely accurate measurements of atomic states for quantum computation


More Information:
S. Subhankar et al., Nanoscale Atomic Density Microscopy, Physical Review X (2019). DOI: 10.1103 / PhysRevX.9.021002

Provided by
National Institute of Standards and Technology

References :
Researchers shed new light on the atomic "wave function" (2019, May 16)
drawn up on 16 May 2019
from https://phys.org/news/2019-05-atomic-function.html

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