Researchers validate several fluctuation theorems for first time

February 23, 2018 by Kayla Zacharias, Purdue University
Researchers experimentally tested the differential fluctuation theorem using an optically levitated nanosphere which can be trapped in air continuously for 65 weeks, acquiring large sets of data. Credit: Tongcang Li

Researchers at Purdue University have performed the first experimental tests of several fundamental theorems in thermodynamics, verifying the relationship between them and providing a better understanding of how nanoparticles behave under fluctuation.

As a system gets smaller, fluctuations away from equilibrium begin to dominate its behavior. This makes the data from experiments in small systems, such as biological molecular motors and , messy and difficult to make sense of. Fluctuation theorems help researchers make sense of the fluctuations in these systems.

Fluctuation theorems are refinements of the second law of thermodynamics, which states that all kinds of energy in the material world disperses if it is not hindered from doing so.

A team of researchers from Purdue and Peking University, led by Tongcang Li, assistant professor of physics and astronomy at Purdue, tested the differential fluctuation theorem for work production and several other theorems. They levitated a nanoparticle in a vacuum chamber with a laser, using a tiny optical tweezer to measure instantaneous position and velocity. This mechanism allows them to trap the nanoparticle in air continuously for weeks or months and acquire large sets of data.

The research was published in Physical Review Letters.

Explore further: Physicists extend stochastic thermodynamics deeper into quantum territory

More information: Thai M. Hoang et al. Experimental Test of the Differential Fluctuation Theorem and a Generalized Jarzynski Equality for Arbitrary Initial States, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.120.080602

Related Stories

Fluctuation X-ray scattering

March 26, 2015

In biology, materials science and the energy sciences, structural information provides important insights into the understanding of matter. The link between a structure and its properties can suggest new avenues for designed ...

Recommended for you

Pond dwellers called Euglena swim in polygons to avoid light

September 25, 2018

In any seemingly quiet pond the still waters actually teem with tiny pond dwellers called Euglena gracilis. Unseen to the naked eye, the single-celled organism spirals through the water, pulled along a relatively straight ...

Explainer: The US push to boost 'quantum computing'

September 24, 2018

A race by U.S. tech companies to build a new generation of powerful "quantum computers" could get a $1.3 billion boost from Congress, fueled in part by lawmakers' fear of growing competition from China.

A new way to count qubits

September 24, 2018

Researchers at Syracuse University, working with collaborators at the University of Wisconsin (UW)-Madison, have developed a new technique for measuring the state of quantum bits, or qubits, in a quantum computer.

5 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

KBK
1 / 5 (4) Feb 24, 2018
Fluids and gasses, plasma sheets, charge sheets, microwaves, radio waves, ionic clouds, and so on....

suddenly dominated, in your understanding..FINALLY (jebus, what took you so long!!!!)....dominated by..quantum fluctuations in the thermodynamic aspects. Quantum spooky, dimensional, not obeying Newtonian rules. Thermodynamics can go backward and violates the 'laws of physics' - which are Newtonian in nature.

Quantum has no such rules. And now, you finally understand, that thermodynamics are quantum in nature in those mentioned systems.

When you look at all the stories of multidimensional systems, over unity systems, anti-gravity systems, FTL systems, it all makes sense. Perfect sense.

EG, SHT 'Solar Hydrogen Trends' bought by the military. Their energy conversion system, has a minimum 700% efficiency. Go find photos on the net, from a military trade show.

One of hundreds you will find, if you start looking. It's the next silicon valley, but far bigger. ~100x bigger.
Da Schneib
4 / 5 (4) Feb 24, 2018
I don't think simple levitation can not compensate for these forces. Since the physicists performed their experiments on a single bead over a period of time, one would expect to see these biases in the data.
I didn't follow this. Why would there be Coriolis forces in the experiments?
torbjorn_b_g_larsson
3 / 5 (2) Feb 25, 2018
I note that generic fluctuation theorems, who are important for thermodynamics of biomolecular systems, have been verified in such systems before [ https://en.wikipe..._theorem ].

@jd: "the Differential Fluctuation Theorem is a generalization of Onsager's theory on reciprocal relations ... does not apply when Coriolis forces are present".

First, Onsager's theory is a small fluctuation linearization of macroscale systems [ https://en.wikipe...elations ], while the fluctuation theorems are properties of general fluctuations in microscale systems. Jarzynski's paper on the DFT [ https://arxiv.org...8286.pdf ] mentions that these are arguably properties of spacetime histories.

And as such these properties rely on nothing more than detailed balance of microscale processes. Coriolis effects are macroscale of rotating systems, not microscale of collisions and statistical fluctuations.

[tbctd]
torbjorn_b_g_larsson
3 / 5 (2) Feb 25, 2018
[ctd] Second, the lab system is not subject to Coriolis forces at all; it is rotating with Earth.

@KBK: "quantum fluctuations".

*All* statistical fluctuations. Most biochemical processes are classical on the scale of chemical processes.

@mackita: "It's all about the the fact, that quantum mechanics violates 2nd thermodynamic law."

The fluctuation theorems are all about the exact opposite fact, based on and thus - successfully according to the article - testing that entropy is increasing. And the other article you point to is also all about the fact that quantities like entropy - and its increase - are found in quantum systems. Are you not reading your so called "references"?

Also, no one denies that fluctuations, whether classical or quantum, leads to microscale violations of macroscale entropy. They are, to use a meme, the exceedingly rare (as seen on macroscale) exceptions that proves the rule.
Da Schneib
not rated yet Feb 25, 2018
You didn't tell us what effect you think Coriolis forces have, @jd. I'm assuming you can't justify it. Which would make you the idiot who knows nothing about physics.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.