The strive to reach absolute zero or zero degrees on the Kelvin scale has been going on for decades. This is equal to negative 273.15 degrees on the Celsius scale. Physicists at the University of Basel have managed to set a new record for the lowest temperature achieved and have been successful in cooling a nanoelectronic chip to a temperature of less than 3 milliKelvins.
Researchers from the Department of Physics and the Swiss Nanoscience Institute in collaboration with scientists from Germany and Finland used magnetic fields to eliminate heat from the electrical connections as well as the chip itself. The reason everyone wants to achieve absolute zero is that it provides the perfect conditions for quantum experiments and allows new physical phenomenon to be studied.
Professor Dominik Zumbühl is the physicist from Basel leading the team of scientists. They used magnetic cooling to achieve such low temperatures. The phenomenon works when a magnetic field is ramped down while at the same time avoiding external heat.
The scientists used the magnetic field to cool the chip and surroundings to 150 Kelvins. Then, they used a separate magnetic field to cool down the Coulomb blockade thermometer because even that heat would cause a hindrance in reaching their goal. “The combination of cooling systems allowed us to cool our chip down to below 3 milliKelvins, and we are optimistic that we can use the same method to reach the magic 1 millikelvin limit,” says Zumbühl.
The chip was able to maintain this cold temperature for seven hours and this seven-hour time period will allow the scientists to conduct their experiments in a condition where there almost no particle motion. These experiments at near almost zero temperatures will be very helpful for quantum physics and we will see that this will open many new avenues for research.
We will have to wait and see if anyone is able to reach a temperature even lower than 3 milliKelvins.