Empty space is not truly empty. Even a vacuum contains restless quantum fluctuations, and researchers have now shown for the first time that these normally subtle effects can be engineered to strengthen superconductivity.
The work, led by Changgan Zeng and Guanghui Cheng of the University of Science and Technology of China of the Chinese Academy of Sciences, with Qingdong Jiang of Shanghai Jiao Tong University, Frank Wilczek of the Massachusetts Institute of Technology, and other collaborators, was published in Nature.
In quantum electrodynamics, the Heisenberg uncertainty principle means that even the lowest energy state retains unavoidable activity as virtual particles continually appear and disappear. These quantum fluctuations fill what might otherwise seem like empty space. Their existence is supported experimentally by well-known effects including the Lamb shift, spontaneous emission, and the Casimir effect.
Zeng and Cheng have spent recent years investigating how these vacuum fluctuations affect condensed matter systems. In an earlier study, their team directly controlled vacuum fluctuations by using a magnetic field to reversibly switch the Casimir force from attraction to repulsion. That result raised a larger question: Could vacuum fluctuations also be used to manipulate macroscopic quantum states?
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