Nanoparticles found to violate second law of thermodynamics


April 3, 2014

A rendering of a nanoparticle trapped in a laser and in thermal non-equilibrium (Image: Iñaki Gonzalez and Jan Gieseler)

A rendering of a nanoparticle trapped in a laser and in thermal non-equilibrium (Image: Iñaki Gonzalez and Jan Gieseler)

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It may be a little late for April Fool’s, but some skepticism is nonetheless warranted when reading that researchers have shown nanoparticles to disobey a fundamental law of physics which dictates the flow of entropy and heat in, it was believed, any situation. Specifically, researchers from three universities theoretically proposed then demonstrated that a nanoparticle in a state of thermal non-equilibrium does not always behave as larger particles might under the same conditions, with implications for various fields of research.

The second law of thermodynamics is the one that makes perpetual motion machines impossible. It states that the entropy – the measure for the disorder of a system – of any isolated system cannot decrease spontaneously, with the system evolving towards the state of maximum entropy (favoring disorder). The team has shown that a nanoparticle trapped with laser light temporarily violates this law. This seeming violation of universal law is transient, something that the researchers first derived as a mathematical model of fluctuations expected at the nanoscale.

To test their theorem, scientists at the University of Vienna, the Institute of Photonic Sciences in Barcelona and the Swiss Federal Institute of Technology in Zürich trapped a nanosized silica sphere with a radius of less than 75 nm in a laser "trap." Not only was the particle held in place, but could be precisely measured in three different directions, important when your particle is so small that 10,000 of them could line the width of a pinhead.

The nano-sphere was cooled lower than the temperature of the surrounding gas, creating a state of nonequilibrium. At a macro scale, a state of thermal non-equilibrium is what dictates that a snowman melts in a suddenly warming environment by absorbing heat from its surroundings, rather than growing more frozen by losing heat. A blindingly obvious example, yet at the nanoscale, such real-life observations are not without exception.

Indeed, by measuring the oscillations in the particle, the researchers were able to determine that the nanoparticle would, at times, effectively release heat to its warming surroundings rather than absorb heat.

Nanoparticles could range from natural parts within cells to man-made devices being developed in medicine and electronics. All of these particles experience random conditions due to their tiny scale. Both this experimental setup and the fluctuation theorem represent new ways to assess how nanoscale technology might fare when exposed to random environmental buffetings. Further studies are planned to further explore this phenomenon.

The research was originally published in Nature Nanotechnology.

Source: University of Vienna

About the Author
Heidi Hoopes Heidi measures her life with the motley things she's done in the name of scientific exploration. While formally educated in biology and chemistry, informally she learns from adventures and hobbies with her family. Her simple pleasures in life are finding turtles while jogging and obsessively winnowing through her genetic data. All articles by Heidi Hoopes

Hmmm, havent techies been using laser cooling for decades now?, especially in creating bose einstein condensates. I think that they might have re invented this wheel.

It occurs when a longer wave length laser excites a shorter wave length resonance. the particle is triggered to emit more energy than it received. it still doesnt violate any of the thermo laws.


A simpler to understand version of the second law of thermodynamics is "You can't win, you can't break even, and you can't get out of the game."

@ Alzie

If it is laser cooling it is a safe bet that the cooling was not consistent with previous experiences with laser cooling.


I have a fabric here that defies the laws of thermo dynamics too

It's ordinary old ripstop nylon used in sails

When its' hot it shrinks and gets as tight as a drum when it's cold it expands and goes all wrinkly

Go figure!

Philip Morgan

Is this bumping up against Heisenberg's uncertainty as the size approaches quantum scales? Or maybe it's an instrumentation issue like the faster than light neutrinos in Italy. These more than just good ideas, these are laws that constitute the recipe for a universe.


@ Philip Morgan That is not thermodynamics. The gridiron pendulum keeps the weight at the same distance from the pivot point despite every piece getting longer with heat by balancing the the pieces that lift the weight when they expand against the pieces that lower the weight when they expand except the nylon's internal structure in out of balance so that the lifting effect is greater than the lowering force.


Perpetual motion machines are impossible by the First Law of Thermodynamics too. it says you can neither create nor destroy energy. A perpetual motion machine would have to create energy to overcome frictional losses (which might be low but still there).


@ warren52nz It is conceptually possible to make a perpetual motion machine that does not create energy merely gathers the energy from around it in the reverse of entropy.


"In this house we obey the laws of thermodynamics! "

Homer simpson.

Stephen Hall

Not the first time that the laws appear to be broken, The Casimir effect also breaks those laws.

I await ever-lasting batteries!!


How is this a closed system?

Theotherone Or
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