TY - JOUR
T1 - Trace expressions and associated limits for nonequilibrium Casimir torque
AU - Strekha, Benjamin
AU - Molesky, Sean
AU - Chao, Pengning
AU - Krüger, Matthias
AU - Rodriguez, Alejandro W.
N1 - Funding Information:
This work was supported by the National Science Foundation under the Emerging Frontiers in Research and Innovation (EFRI) program, EFMA-1640986, the Cornell Center for Materials Research (MRSEC) through award DMR-1719875, the Defense Advanced Research Projects Agency (DARPA) under agreements HR00112090011, HR00111820046, and HR0011047197, and the Canada First Research Excellence Fund via the Institut de Valorisation des Données (IVADO) collaboration. The views, opinions, and findings expressed herein are those of the authors and should not be interpreted as representing the official views or policies of any institution.
Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/10
Y1 - 2022/10
N2 - We exploit fluctuational electrodynamics to present trace expressions for the torque experienced by arbitrary objects in a passive, nonabsorbing, rotationally invariant background environment. Specializing to a single object, this formalism, together with recently developed techniques for calculating bounds via Lagrange duality, is then used to derive limits on the maximum Casimir torque that a single object with an isotropic electric susceptibility can experience when out of equilibrium with its surrounding environment. The maximum torque achievable at any wavelength is shown to scale in proportion to body volumes in both subwavelength (quasistatics) and macroscopic (ray optics) settings, and come within an order of magnitude of achievable torques on topology optimized bodies. Finally, we discuss how to extend the formalism to multiple bodies, deriving expressions for the torque experienced by two subwavelength particles in proximity to one another.
AB - We exploit fluctuational electrodynamics to present trace expressions for the torque experienced by arbitrary objects in a passive, nonabsorbing, rotationally invariant background environment. Specializing to a single object, this formalism, together with recently developed techniques for calculating bounds via Lagrange duality, is then used to derive limits on the maximum Casimir torque that a single object with an isotropic electric susceptibility can experience when out of equilibrium with its surrounding environment. The maximum torque achievable at any wavelength is shown to scale in proportion to body volumes in both subwavelength (quasistatics) and macroscopic (ray optics) settings, and come within an order of magnitude of achievable torques on topology optimized bodies. Finally, we discuss how to extend the formalism to multiple bodies, deriving expressions for the torque experienced by two subwavelength particles in proximity to one another.
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U2 - 10.1103/PhysRevA.106.042222
DO - 10.1103/PhysRevA.106.042222
M3 - Article
AN - SCOPUS:85141619878
SN - 2469-9926
VL - 106
JO - Physical Review A
JF - Physical Review A
IS - 4
M1 - 042222
ER -