A group of scientists from the RIKEN Center for Emergent Matter Science in Japan has succeeded in taking repeated measurements of the spin of an electron in a silicon quantum dot (QD) without changing its spin in the process. This type of “non-demolition” measurement is important for creating quantum computers that are fault-tolerant. Quantum computers would make it easier to perform certain classes of calculations such as many-body problems, which are extremely difficult and time-consuming for conventional computers. Essentially, the involve measuring a quantum value that is never in a single state like a conventional transistor, but instead exists as a “superimposed state”—in the same way that Schrodinger’s famous cat cannot be said to be alive or dead until it is observed. Using such systems, it is possible to conduct calculations with a qubit that is a superimposition of two values, and then determine statistically what the correct result is. Quantum computers that use single electron spins in silicon QDs are seen as attractive due to their potential scalability and because silicon is already widely used in electronics technology.
Click here for original story, Scientists measure electron spin qubit without demolishing it
Source: Phys.org