1
|
Jiang Z, Chen F, Kou Z, Yin J, Liu X, Guo W. Large Casimir Flipping Torque in Quantum Trap. J Phys Chem B 2024; 128:350-357. [PMID: 38151461 DOI: 10.1021/acs.jpcb.3c06922] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Casimir torque between parallel plates, a macroscopic quantum electrodynamics effect, is known to be induced by dielectric anisotropy and related to the rotational degree of freedom. We here reveal a different type of Casimir torque generated on a Au plate suspended in a quantum trap without recourse to materials anisotropy. As the Au plate deflects from the equilibrium plane with a nonzero flipping angle, the regions departing from and approaching the Teflon-coated Au substrate are subjected to attractive and repulsive Casimir forces, respectively, resulting in a restoring torque about the axis of flipping. For a quantum trap with an equilibrium separation of ∼10 nm, the stiffness per unit area of the Casimir flipping torque can be an order of magnitude larger than those of previously reported dielectric anisotropy-induced rotational torques at the same separation. The large Casimir flipping torque provides the possibility of designing a mechanical oscillator completely dominated by quantum and thermal fluctuations.
Collapse
Affiliation(s)
- Zonghuiyi Jiang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Fangyuan Chen
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Zepu Kou
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Jun Yin
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Xiaofei Liu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| |
Collapse
|
2
|
Chen L, Chang K. Chiral-Anomaly-Driven Casimir-Lifshitz Torque between Weyl Semimetals. PHYSICAL REVIEW LETTERS 2020; 125:047402. [PMID: 32794785 DOI: 10.1103/physrevlett.125.047402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We propose a new mechanism to generate the Casimir-Lifshitz torque between Weyl semimetals arising from the chiral anomaly. For short distances ranging from a nanometer to a few tens of nanometers, chiral anomaly is manifested via a Casimir-Lifshitz torque ∼sin(θ) with θ being the twisting angle. As the distance between Weyl semimetals increases from a submicrometer to a few micrometers, chiral-anomaly-driven Casimir-Lifshitz torque between Weyl semimetals is remarkably large, which is comparable with that of conventional birefringent materials.
Collapse
Affiliation(s)
- Liang Chen
- Mathematics and Physics Department, North China Electric Power University, Beijing 102206, China
| | - Kai Chang
- SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| |
Collapse
|
3
|
Antezza M, Chan HB, Guizal B, Marachevsky VN, Messina R, Wang M. Giant Casimir Torque between Rotated Gratings and the θ=0 Anomaly. PHYSICAL REVIEW LETTERS 2020; 124:013903. [PMID: 31976735 DOI: 10.1103/physrevlett.124.013903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Indexed: 06/10/2023]
Abstract
We study the Casimir torque between two metallic one-dimensional gratings rotated by an angle θ with respect to each other. We find that, for infinitely extended gratings, the Casimir energy is anomalously discontinuous at θ=0, due to a critical zero-order geometric transition between a 2D- and a 1D-periodic system. This transition is a peculiarity of the grating geometry and does not exist for intrinsically anisotropic materials. As a remarkable practical consequence, for finite-size gratings, the torque per area can reach extremely large values, increasing without bounds with the size of the system. We show that for finite gratings with only ten period repetitions, the maximum torque is already 60 times larger than the one predicted in the case of infinite gratings. These findings pave the way to the design of a contactless quantum vacuum torsional spring, with possible relevance to micro- and nanomechanical devices.
Collapse
Affiliation(s)
- Mauro Antezza
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier, France
- Institut Universitaire de France, 1 rue Descartes, F-75231 Paris Cedex 05, France
| | - H B Chan
- Department of Physics, Center for Metamaterial Research and William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Brahim Guizal
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier, France
| | - Valery N Marachevsky
- St. Petersburg State University, 7/9 Universitetskaya naberezhnaya, St. Petersburg 199034, Russia
| | - Riccardo Messina
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier, France
- Laboratoire Charles Fabry, UMR 8501, Institut d'Optique, CNRS, Université Paris-Saclay, 2 Avenue Augustin Fresnel, 91127 Palaiseau Cedex, France
| | - Mingkang Wang
- Department of Physics and William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| |
Collapse
|
4
|
Somers DAT, Garrett JL, Palm KJ, Munday JN. Measurement of the Casimir torque. Nature 2018; 564:386-389. [DOI: 10.1038/s41586-018-0777-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/25/2018] [Indexed: 11/09/2022]
|
5
|
Fiedler J, Persson C, Boström M, Buhmann SY. Orientational Dependence of the van der Waals Interactions for Finite-Sized Particles. J Phys Chem A 2018; 122:4663-4669. [PMID: 29683677 DOI: 10.1021/acs.jpca.8b01989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dispersion forces, especially van der Waals forces as interactions between neutral and polarizable particles act at small distances between two objects. Their theoretical origin lies in the electromagnetic interaction between induced dipole moments caused by the vacuum fluctuations of the ground-state electromagnetic field. The resulting theory well describes the experimental situation in the limit of the point dipole assumption. At smaller distances, where the finite size of the particles has to be taken into account, this description fails and has to be corrected by higher orders of the multipole expansion, such as quadrupole moments and so on. With respect to the complexity of the spatial properties of the particles this task requires a considerable effort. In order to describe the van der Waals interaction between such particles, we apply the established method of a spatially spread out polarizability distribution to approximate the higher orders of the multipole expansion. We thereby construct an effective theory for effects from anisotropy and finite size on the van der Waals potential.
Collapse
Affiliation(s)
- Johannes Fiedler
- Physikalisches Institut , Albert-Ludwigs-Universität Freiburg , Hermann-Herder-Strasse 3 , 79104 Freiburg , Germany.,Centre for Materials Science and Nanotechnology, Department of Physics , University of Oslo , P.O. Box 1048 Blindern, NO-0316 Oslo , Norway
| | - Clas Persson
- Centre for Materials Science and Nanotechnology, Department of Physics , University of Oslo , P.O. Box 1048 Blindern, NO-0316 Oslo , Norway
| | - Mathias Boström
- Department of Energy and Process Engineering , Norwegian University of Science and Technology , NO-7491 Trondheim , Norway
| | - Stefan Y Buhmann
- Physikalisches Institut , Albert-Ludwigs-Universität Freiburg , Hermann-Herder-Strasse 3 , 79104 Freiburg , Germany.,Freiburg Institute for Advanced Studies , Albert-Ludwigs-Universität Freiburg , Albertstrasse 19 , 79104 Freiburg , Germany
| |
Collapse
|