New discovery helps close the gap towards optically-controlled quantum computation


Scientists have discovered a light-induced switching mechanism in a Dirac semimetal.

Scientists at Ames Laboratory, Brookhaven National Laboratory, and the University of Alabama Birmingham have discovered a light-induced switching mechanism in a Dirac semimetal. The mechanism establishes a new way to control the topological material, driven by back-and-forth motion of atoms and electrons, which will enable topological transistor and quantum computation using light waves.

Just like today's transistors and photodiodes replaced vacuum tubes over half a century ago, scientists are searching for a similar leap forward in design principles and novel materials in order to achieve quantum computing capabilities. Current computation capacity faces tremendous challenges in terms of complexity, power consumption, and speed; to exceed the physical limits reached as electronics and chips become hotter and faster, bigger advances are needed. Particularly at small scales, such issues have become major obstacles to improving performance.

"Light wave topological engineering seeks to overcome all of these challenges by driving quantum periodic motion to guide electrons and atoms via new degrees of freedom, i.e., topology, and induce transitions without heating at unprecedented terahertz frequencies, defined as one trillion cycles per second, clock rates," said Jigang Wang, a senior scientist at Ames Laboratory and professor of physics at Iowa State University. "This new coherent control principle is in stark contrast to any equilibrium tuning methods used so far, such as electric, magnetic and strain fields, which have much slower speeds and higher energy losses."

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