In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir energy.The Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic vacuum.Pre...In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir energy.The Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic vacuum.Previous experiments have used nano-or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two surfaces.In this new set of experiments,we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates,one of which is a superconductor.A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature(T_(c))because of the interaction between it and the superconducting condensation energy.In our experiment,we take a superconducting film,carefully measure its transition temperature,bring a conducting plate close to the film,create a Casimir cavity,and then measure the transition temperature again.The expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures,so using a NEMS resonator in situ is the only practical way to obtain accurate,reproducible data.Using a thin Pb film and opposing Au surface,we observe no shift in T_(c)>12µK down to a minimum spacing of~70 nm at zero applied magnetic field.展开更多
基金This work is supported in part by the Cooperative Research Agreement between the University of Maryland and the National Institute of Standards and Technology Center for Nanoscale Science and Technology,Award 70NANB10H193,through the University of MarylandAdditional support of this work is provided by the National Science Foundation under Grants EEC-1647837,ECCS-1708283,EEC-0812056,a SONY Faculty Innovation Award,and DARPA/AFRL through award FA8650-15-C-7545。
文摘In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir energy.The Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic vacuum.Previous experiments have used nano-or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two surfaces.In this new set of experiments,we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates,one of which is a superconductor.A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature(T_(c))because of the interaction between it and the superconducting condensation energy.In our experiment,we take a superconducting film,carefully measure its transition temperature,bring a conducting plate close to the film,create a Casimir cavity,and then measure the transition temperature again.The expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures,so using a NEMS resonator in situ is the only practical way to obtain accurate,reproducible data.Using a thin Pb film and opposing Au surface,we observe no shift in T_(c)>12µK down to a minimum spacing of~70 nm at zero applied magnetic field.
