The team used laser light and optics to construct an image of the atomic wave function (shown as violet). Graphics are an artistic representation of this process, which demonstrates an optical microscope trained on atoms (domains) suspended in an optical grid (high white waves). The team's technique reveals information about the atomic wave function unprecedented. Credit: E. Edwards / A Unified Quantum Institute
Physicists have demonstrated a new way of obtaining basic details that describe an isolated quantum system, such as atomic gas, by direct observation. The new method gives information about the probability of finding atoms in certain places in a system with an unprecedented spatial resolution. With this technique, scientists can get details on scales from tens of nanometers – less than the width of the virus.
Experiments conducted at the Institute of the Unified Quantum (JQI), a research partnership between the National Institute of Standards and Technology (NIST) and the University of Maryland, use an optical grid – a laser light network that pauses thousands of individual atoms – to determine the probability that that the atom can be in any particular place. Since each individual atom in the lattice behaves in the same way as all others, then measurements across the entire group of atoms show that the probability that a single atom is at a certain point in space.
A JQI technique (and a similar technique published simultaneously by a group at the University of Chicago) in the journal Physical Review X may give the possibility that the arrangement of atoms will be much lower than the wavelength of light used to illuminate the atoms – 50 times better The limit that optical microscopy can normally solve.
"This is a demonstration of our ability to observe quantum mechanics," said Trey Porto, one of the physicists behind the research. "It was not done with atoms with any near this accuracy."
To understand the quantum system, physicists often talk about its "wave function". This is not just an important detail; this is the whole story. It contains all the information needed to describe the system.
"This is a description of the system," said JQI physicist Steve Rolston, another author of the article. "If you have information about the wave function, you can calculate everything else about it – for example, the object's magnetism, its conductivity, and the probability of radiation or light absorption."
Although the wave function is a mathematical expression, and not a physical object, the team method can disclose the behavior described by the wave function: the probability that a quantum system will behave in one direction against another. In the world of quantum mechanics, the probability is all.
Among the many strange principles of quantum mechanics is the idea that before we measure our positions, the objects may not have the exact location. The electrons surrounding the nucleus of an atom, for example, do not travel in regular planetary orbits, contrary to the image of some of us who were studying at the school. On the contrary, they act as pulsating waves, so that the electron itself can not have a definite location. Most likely, the electrons are in the fuzzy areas of space.
All things may have such a wave-like behavior, but for any eye-sight that is not third-sighted, the effect is unobtrusive, and the rules of classical physics are valid-mark buildings, buckets or crackers that are spread like waves. But isolate a tiny object such as an atom, and the situation is different, because the atom exists in the area where quantum mechanics affects. It is impossible to say with certainty where he is located, only that he will be found somewhere. The wave function provides a set of probabilities that the atom will be found in any place
Quantum mechanics is quite well understood – physicists, one way or another – for a simple system, experts can calculate the wave function from the first principles without having to adhere to it. However, many interesting systems are complicated.
"There are quantum systems that can not be calculated because they are too complex," Rolston said, for example, of molecules of several large atoms. "This approach can help us understand these situations."
Since the wave function describes only a set of probabilities, how can physicists get a complete picture of its effects in short terms? The team approach involves the simultaneous measurement of a large number of identical quantum systems and the aggregation of results into one common picture. This is similar to how to simultaneously pump 100,000 pairs of bones – each role gives one result, and inserts one point on the probability curve, indicating the values of all bones.
Approximately 100,000 atoms of yerbium are suspended in their lasers by an optical grating. Atmospheric yttrium is isolated from its neighbors and is limited to moving forward and backward in a one-dimensional segment. To get a high-resolution shot, the team found a way to observe the narrow fragments of these line segments and how often each atom was in the appropriate slice. After observing one region, the team measured another until she had the whole picture.
Rolston said that while he had not yet thought about a "kill program" that would take advantage of the technique, the fact that the team directly portrayed something central to quantum research.
"It's not entirely obvious where it will be used, but it is a new technology that offers new opportunities," he said. "We are using an optical grid to capture atoms for many years, and now it has become a new measure of measurement."
Extremely accurate measurements of atom states for quantum computing
S. Subhankar et al., Nanoscale Atomic Density Microscopy, Physical Review X (2019). DOI: 10.1103 / PhysRevX.9.021002
National Institute of Standards and Technology
Researchers shed light on the atomic "wave function" (2019, May 16)
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