Due to quantum effects, it's possible to build a quantum computer that computes without running—or as the scientists explain, "the result of a computation may be learned without actually running the computer." So far, however, the efficiency of this process, which is called counterfactual computation (CFC), has had an upper limit of 50%, limiting its practical applications.
Now in a new paper, scientists have experimentally demonstrated a slightly different version called a "generalized CFC" that has an efficiency of 85% with the potential to reach 100%. This improvement opens the doors to realizing a much greater variety of applications, such as low-light medical X-rays and the imaging of delicate biological cells and proteins—in certain cases, using only a single photon.
The researchers, led by Prof. Jiangfeng Du at the University of Science and Technology of China and Prof. Liang Jiang at Yale University in the US, have published a paper on the high-efficiency counterfactual computing method in a recent issue of Physical Review Letters.To read more, click here.