One of the greatest scientific research of our time is the hunt for dark matter. Physicists believe that this substance fills the universe and think you can see evidence of this in how to spin the galaxy. The fact that galaxies rotate so fast that they had to break apart, but apparently (or invisibility), there is some hidden mass, which has sufficient gravitational force to hold them together.
This has forced physicists to search for dark matter on Earth. They built dozens of observatories, most of which are in underground caves far beneath the surface, where the background noise is low. At stake is scientific glory, and those who find dark matter will be richly rewarded.
Why dark matter can’t find?
Yet physicists didn’t find anything. If dark matter exists, it is extremely well hidden. One possibility is that dark matter particles are too small to be found in the ongoing experiments. Physicists desperately want to find a more sensitive way to search for such substances.
Yonit Hochberg of the Hebrew University of Jerusalem in Israel and his colleagues have developed a promising new sensor-based tiny superconducting wires. The prototype team is already showing the potential of this approach.
The new device is a simple principle. Cool certain metals below a critical temperature and they will conduct electricity without resistance. But as soon as their temperature rises above this threshold, the superconducting behavior disappears.
Physicists know what dark matter particles can not strongly interact with visible matter; otherwise, they would have seen them. But dark matter particles can collide with regular particles.
This collision occur rarely, because the matter is a mostly empty space and dark matter particles can pass right through it. But when they encounter an atomic nucleus or electron in the lattice, for example, a collision causes vibrations in the lattice, thereby increasing its temperature.
This temperature rise is well identified superconducting nanowires. The heat causes a small portion of the wires ceases to be superconducting, and this, in turn, creates a voltage pulse that is easily measured. Moreover, such a device produces few false positives, if at all.
Hochberg and colleagues tested their idea by creating a prototype. This device consists of a set of silicide nanowires of tungsten with a width of 140 nanometers (for comparison, the width of a human hair is 100,000 nanometers) and a length of 400 micrometers. The whole apparatus is only a few Milli-degrees above absolute zero, so that wires of tungsten silicide become superconductors.
The team then watched the voltage pulses, which could detect the collision of dark matter. With proper screening, they found no pulse in 10,000 seconds of measurements.
This imposes important restrictions on the type of dark matter that could exist, and its density. It also imposes restrictions on other types of particles, as suggested by physics, can exist.
One of these types — the “dark photon”, essentially the equivalent of a normal photon from dark matter. If any, the new detector has not detected any. “The results obtained with this device has already been set meaningful boundaries for the interaction between dark matter and electrons, including the most powerful of earth’s boundaries to absorb such photons at less than eV,” says Hochberg.
The work is impressive, given that the mass of the nanowires is only a few nanograms. The next step will be producing them in larger scale. Hochberg and colleagues say that the technology is relatively Mature, so it can be tested in a short time. According to their estimates, the science lab will be able to produce a thousand 200-nm detectors with a total mass of 1.3 grams in just one year. So pound the detector may be feasible in the near future.
Maybe one day, a superconducting nanowires detect dark matter if it exists. What do you think exists? Tell us in our chat in Telegram.