&Bullet; physics 14, s54

An experiment with a nanoscale clock confirms that the entropy of a clock increases per tick as the clock is made more precise.

banusevim / stock.adobe.com

Entropy generally increases with every tick of time, so it is natural for a timepiece to produce an increase in entropy during operation. Building on earlier work with quantum clocks, researchers are now showing that a simple classic clock – the ticks of which are the vibrations of a heat-driven, nanometer-thick membrane – generates more entropy with increasing precision [1] . The experiments open a new line to investigate how nanomachines can convert random input into useful work.

A clock is a machine and, like all machines, obeys the laws of thermodynamics. Previous studies have looked at quantum clocks and found a linear relationship between their accuracy and the entropy they create (see Viewpoint: The Thermodynamic Costs of Timekeeping). However, whether this relationship holds true for classic watches is uncertain as it is more difficult to track the energy in and out of these larger devices.

Natalia Ares of Oxford University, UK, and colleagues designed a classic clock with adjustable precision that allowed them to measure energy flows. Their system consisted of a silicon nitride membrane that was suspended over metal electrodes and formed a tiny cavity.

The researchers applied a noisy signal to the electrodes, causing the membrane to vibrate at a resonant frequency. A circuit connected to the cavity measured the membrane vibrations and registered a “tick” for each vibration cycle. By increasing the energy or “heat” in the input signal, the team was able to increase the vibration amplitude and thereby improve the precision of the membrane measurements. They found that the entropy costs – estimated by measuring the heat loss in the probe circuit – increased linearly with accuracy in accordance with the behavior of the quantum clock.

–Michael Schirber

Michael Schirber is the corresponding editor for physics based in Lyon, France.

References

  1. A Pearson et al., “Measurement of the thermodynamic costs of time measurement” Phys. Rev. X.11021029 (2021).

Subject areas

Quantum Physics Statistical Physics

On the subject of matching items

A recipe for universal vaccines
Nonlinear Dynamics

A recipe for universal vaccines

Researchers use non-equilibrium physics statistical methods to guide the design of vaccines that are effective against many strains of the virus, a holy grail of immunology. Continue reading “

Finding light in dark atomic clouds
Make quantum dynamics exactly
Quantum physics

Make quantum dynamics exactly

Three new studies provide analytical descriptions and precise solutions for various aspects of thermodynamics in quantum many-body systems. Continue reading “

More articles

LEAVE A REPLY

Please enter your comment!
Please enter your name here