Stable Casimir equilibria and quantum trapping

Rongkuo Zhao; Lin Li; Sui Yang; Wei Bao; Yang Xia; Paul Ashby; Yuan Wang; Xiang Zhang

doi:10.1126/science.aax0916

Stable Casimir equilibria and quantum trapping

Science. 2019 Jun 7;364(6444):984-987. doi: 10.1126/science.aax0916.

Authors

Rongkuo Zhao^#¹, Lin Li^#¹, Sui Yang^#¹, Wei Bao^#¹, Yang Xia¹, Paul Ashby², Yuan Wang¹, Xiang Zhang^{3

4}

Affiliations

¹ Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California at Berkeley, Berkeley, CA 94720, USA.
² Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
³ Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California at Berkeley, Berkeley, CA 94720, USA. xiang@berkeley.edu.
⁴ Faculties of Sciences and Engineering, University of Hong Kong, Hong Kong, China.

^# Contributed equally.

PMID: 31171696
DOI: 10.1126/science.aax0916

Abstract

The Casimir interaction between two parallel metal plates in close proximity is usually thought of as an attractive interaction. By coating one object with a low-refractive index thin film, we show that the Casimir interaction between two objects of the same material can be reversed at short distances and preserved at long distances so that two objects can remain without contact at a specific distance. With such a stable Casimir equilibrium, we experimentally demonstrate passive Casimir trapping of an object in the vicinity of another at the nanometer scale, without requiring any external energy input. This stable Casimir equilibrium and quantum trapping can be used as a platform for a variety of applications such as contact-free nanomachines, ultrasensitive force sensors, and nanoscale manipulations.