(LR): John Clark, Michelle H. Dover and John M. Martinis.
Credit: Niklas Elmehed/Nobel Pread Outreach
From subatomic to macro -branded
Clark, Devoret and Martini were the first to demonstrate that quantum effects, such as quantum tunneling and quantification of energy, can work on a macroscopic scale, and not on one particle at a time.
Having received a doctoral degree at the university, Clark came to the University of California in Berkeley, as a post -house, ultimately joining the teachers in 1969. By the mid-1980s, Devoret and Martinis joined the Clark laboratory as a post-house and graduate student, respectively. The trio decided to find evidence of a macroscopic quantum tunneling using a specialized scheme called Josephson’s connection – a macroscopic device that uses the advantages of a tunnel effect, which is currently widely used in quantum calculations, quantum sounding and cryptography.
Josephson Junction, called the British physicist Brian Josephson, who won the 1973 Nobel Prize in physics, is mainly two semiconductor works, separated by an insulating barrier. Despite this small gap between the two conductors, the electrons can still a tunnel through the insulator and create current. This occurs at fairly low temperatures, when the connection becomes superconducting, when the electrons form the so -called “Cooper of a couple. “
The team created a generator based on an electrical circuit on a microchip, about one centimeter-to the essence, a quantum version of a classic pendulum. Their biggest problem was to find out how to reduce the noise in their experimental apparatus. For their experiments, they first submitted a weak current to the connection and measured the voltage – during the entire zero. Then they increased the current and measured how much time it would be required for the system to leave the tunnel from a closed state to get voltage.
Credit: Johan Yarlnestad/Royal Swedish Academy of Sciences
They took a lot of measurements and found that the average current increased as the device temperature drops, as expected. But at some point, the temperature has become so low that the device has become superconducting, and the average current became independent of the temperature of the device – the control signature of macroscopic quantum tunneling.
