The neutrons in the double slit experiment actually take both paths individually

An important principle of quantum mechanics was confirmed by a variety of thought experiments proposed by Einstein, made possible by technological progress. The researchers provided evidence for quantum superposition using individual particles, rather than statistical techniques.

A team of scientists performed Double slit experiment Using neutrons, adding spin measurement equipment to examine the path each neutron takes with the accuracy of previous generations only physicists imagined. in the magazine Physical Review Research The authors reported a result consistent with the neutron splitting itself, with a portion of it passing through each slit.

Dr. Stefan Spooner From the Atomic Institute at TU Wien and co-authors used a standard beam splitter so that neutrons can travel along two possible paths. They applied a magnetic field to just one path, and then measured the effect on the spin of each neutron.

“The results show that individual particles encounter a specific portion of the applied magnetic field in one of the paths, indicating that a portion or multiple of the particle is present in the path before the overlap of the two paths is recorded,” the paper claims. “Having a path obtained […] It’s not a statistical average but it applies to each individual neutron.”

Schematic of the experiment. A standard two-pronged experiment but with neutrons, not protons, and a magnetic field in one path to alter the neutron’s spin. Image Credit: Lemmel et al./Physical Review Research

The work confirms a claim that physicists have been making for nearly a century, but through a method many considered impossible.

An introduction to quantum physics courses usually involves a two-slit experiment, in which two narrow gaps are highlighted in a chip before hitting the screen behind it. In the world familiar to us, water passing through two slits like this creates an interference pattern where the two waves interact. Meanwhile, solid objects, such as base balls, pass through one slit or another and do not interfere with each other afterwards.

Light, or subatomic particles, combine the two. Spoonar said in statement. “The particles move as a wave through the two slits at the same time, and then the two partial waves interfere with each other. In some places they strengthen each other, in other places they cancel each other out.”

This is a demonstration of how things, at the level of very small things, can be particles and waves.

Physicists have demonstrated this effect for decades, reducing the light emitted from the source to such a low level that only one photon reaches the chip at a time. When this happens, the photon interferes with itself as if there were several photons, some going through a slit and some through the other, proving its dual nature. The passage of a photon through both slits simultaneously is an example of quantum superposition, where an object exists in two places simultaneously.

However, just as students decide that these quantum objects are not as hard to understand as they are told, they are hit with a curve kick. Measurement of the passage of a photon And the overlay will be lost, (at least if The measurement is reliable). The act of observing changes the outcome. To avoid this and detect the superposition in action, it was necessary to use statistical analysis of where multiple photons land on the screen.

Here, the team replaced the photon with a neutron. However, they claimed to have measured the neutron without the measurement destroying the superposition. The authors’ advanced equipment was able to quantify the change in the spin of each neutron by the magnetic field without distorting the results.

“When measuring a single particle, our experiment shows that it must have traveled two paths at the same time and unambiguously determines the relevant ratios,” Spoonar He said. The experiment, if confirmed, would terminate posterior protection attempts to explain the results of previous double-slit experiments without resorting to superposition.