Synopsis

Reducing Vibrations in Mechanical Beams

Physics 9, s140
A vibrating beam could be cooled to its mechanical ground state by coupling its bending and stretching modes via an electronic defect placed in the beam.
K. V. Kepesidis et al., Phys. Rev. B (2016)

A standard technique for cooling atoms is hitting them with photons. The atoms’ kinetic energy—their temperature—changes with each absorbed or emitted photon, and this process can be tuned such that the atoms get colder. Now Kosmas Kepesidis, from Technische Universität Wien (Vienna) in Austria, and colleagues have proposed an analogous method for “cooling” a tiny bending beam, which uses phonons—vibrational quanta—instead of photons. If realized, this new method could significantly broaden the number of nanomechanical systems that could be cooled.

In their proposed method, the researchers consider a diamond nanobeam bending above a magnetic tip (the beam is clamped at one end and free to move at the other). Near the oscillating end they insert a lattice defect, specifically a silicon-vacancy center. As the beam bends, the defect experiences a varying magnetic field, which can flip its spin by absorbing mechanical energy from the beam’s low-frequency bending modes. If the defect is then stimulated with microwaves into an excited state, this energy is dissipated via emission of a high-frequency lattice phonon. According to the team’s predictions, the mechanical temperature of the beam—how much it bends—can then be tuned by optimizing these absorption and emission processes in the same way that the temperature of atoms can be controlled with light. The researchers propose that this method could also be used to squeeze and entangle different bending modes of the beam.

This research is published in Physical Review B.

–Katherine Wright

Katherine Wright is a Contributing Editor for Physics.


Subject Areas

Condensed Matter Physics

Related Articles

Postponing Heat Death in Periodically Driven Systems
Condensed Matter Physics

Postponing Heat Death in Periodically Driven Systems

An exponential suppression of heating has been observed in a periodically driven optical lattice, opening up an opportunity to engineer new states of matter. Read More »

Spin Current in an Antiferromagnet is Coherent
Condensed Matter Physics

Spin Current in an Antiferromagnet is Coherent

Experiments show that a spin current moves as a coherent evanescent spin wave through an antiferromagnet layer sandwiched between two ferromagnets. Read More »

Topological States in a Segmented Chain
Condensed Matter Physics

Topological States in a Segmented Chain

A segmented chain of molecules held together by van der Waals forces may host spin-polarized, topologically protected electron states. Read More »

More Articles