Researchers report reversal of current flow in a quantum system

Energy against the current on a quantum scale, without contradicting the laws of physics
Artist's impression of the role of a quantum observer: depending on where the observer is positioned, and what part of the figure is seen, the water will be seen to flow differently. Credit: © K. Aranburu

In a classical thermodynamic system, heat current flows from the hotter body to the colder one, or electricity from the higher voltage to the lower one. The same thing happens in quantum systems, but this state can be changed, and the flow of energy and particles can be reversed if a quantum observer is inserted into the system.

This is the main result obtained by the group led by Professor Ángel Rubio of the UPV/EHU and of the Max Planck Institute PMSD, together with collaborators at the BCCMS centre in Bremen. Their study has been published in npj Quantum Materials.

In macroscopic objects such as a current of water, observing the current does not affect the flow of the water and, in accordance with the laws of classical thermodynamics, this flow would take place from the upper to the lower part of the system. However, in , "the process of observation changes the state of the system, and this makes it more likely that the current will be made to flow in one or another," says Ángel Rubio, a professor with the Hamburg-based Max Planck Institute for the Structure and Dynamics of Matter.

Rubio says this does not constitute "an infringement of any fundamental theorem of physics nor is energy created out of nothing. What happens is that inserting an observer into the system acts as an obstacle, as if you were to close off the channel in a pipeline through which the water is flowing. Obviously, if the load starts to build up, it would end up going in the opposite direction. In other words, the observer projects the state of the system onto a state that transmits the current or energy in opposite directions."

Rubio remembers his surprise when discovering that inserting the observer caused the directions of the current and the transfer of energy to change: "Initially, we thought it was an error. We expected to come across changes and we thought it would be possible to halt the transport, but we didn't expect there was going to be a complete change of flow. These changes in the direction of the current can also be made in a controlled way. Depending on where the observer is inserted, the can be changed, but there are specific areas in the device in which, despite looking, the direction does not change," he says.

Difficulties for experimental design

Controlling the heat and current of particles in this way could open up the door to various strategies for designing quantum transport devices with directionality control of the injection of currents for applications in thermoelectrics, spintronics, phononics and detection, among others. But Ángel Rubio believes these applications are a long way off, because he sees limitations in the design of the observers: "We have proposed a simple model, and the theory can be easily verified because all the and entropy flows are preserved. Carrying out this process experimentally would be another matter. Although the type of device that would need to be designed exists, and producing it would be feasible, right now, there is no possibility of doing this in a controlled way."

Thus, the research group is now exploring other, similar ideas. "We're look for other mechanisms as an alternative to quantum observers that would allow similar effects to be achieved and which would be more realistic when it comes to implementing them experimentally," Rubio says.

Explore further

Controlling heat and particle currents in nanodevices by quantum observation

More information: Robert Biele et al, Controlling heat and particle currents in nanodevices by quantum observation, npj Quantum Materials (2017). DOI: 10.1038/s41535-017-0043-6
Citation: Researchers report reversal of current flow in a quantum system (2017, October 9) retrieved 23 October 2019 from
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User comments

Oct 09, 2017
Start searching all the 'over unity' claims out there.

A VERY large number of them will include data on device COOLING, not heating as it normally should, is expected.

Not so crazy anymore, is it?


As for over unity itself, yes the governments and corporations of the world also research it and openly spend billions on it, all the time. It's called Fusion. No different.

The thing about fusion research, is that it allows for centralized control of the population to remain..... keeping the population under the thumb of oligarchy. Fusion it is!!! Nice profit margin too!

Kill off the researchers and ridicule all those reams and reams of published over unity research. Human freedom might accidentally erupt.....

Oct 09, 2017
Fascinating. Another study showing something amazing that we will never hear of again. And it has the word quantum in it too. Now if only there was some way to make quantum effects manifest at the macro level. I know, let's ask Deepak Chopra.

Oct 09, 2017
if a law must persist to satisfy a belief

considering "a system cannot know itself" paradigm

the laws of quantum physics probably may result in
no laws yet possibility


(entropy is as i understand it the basis of the second law of thermodynamics)

= linear perception

as we understand the laws of entropy are simply reversed for negentropy (-time+)

control of the flow information is the thermodynamics of language i.e. topology

then you need to reconsider the speed of light as a resonance of space time density

and work on reverse feedback loops for quantum information dispersal

for example a "negative time crystal" is a battery and a light at the same time
(everlasting memory device i read it was described as)

a "quantum paradox" is a misnomer

Oct 12, 2017
I have an idea/theory based on expanded version of general relativity that explains negative entropy (aka dark matter), the key feature of it is it moves backwards in time - i.e. light travels along the temporal plane (what gravity pushes down on in relativity), dark matter pushes up on it (negative gravity) and mass down on it. So what we might have here is actually a way to measure (and possibly collect) dark matter - which would be a really cool find if true.

Question is...
Would light travel back in time if moving faster than C...
And would it xpress itself as mass, yet unseen...?

Oct 13, 2017
Would light travel back in time if moving faster than C

Light travels at c.
Note that c is not the speed of light but the speed of causality. It is the limit at which something without mass can travel. Since light has no mass that's the speed it's stuck at. It cannot 'speed up' (you can slow it down in a medium - but there other effects come into play)

Nov 01, 2017
er no supposedly "lost" in the Maxwell equations was an aspect of the em field know in obscure references as scalar. scalar is known to physicists in a different but possibly equivocal meaning (this is were I get mixed up due to my laziness and effect of paranoia)... but what ever the truth i.e. a human intervention or a Gaia effect of sorts it seems that when electrical lights started being manufactured this component of the electromagnetic field got "lost" this "lost component" is equivalent to chi and piranha. basically look at a medical symbol this might help you understand wether you took the hypocritical oath or not this symbol carries a lot of information and is older than some languages . it gets stranger many accounts of meditators fixing there sight on a star and becoming enlightened . anyway there are many rabbit holes in the world , if you can handle paradigm shifts then you're a ok

Nov 01, 2017
I meant to write prana not piranha yum yum

Nov 01, 2017
Hippocratic Oath sorry another type'o

Nov 01, 2017
re regarding article in which the comments are closed

phys org news 2017 07 particle currents nanodevices quantum

I'm getting fed up of thought experiments all they do is put a professor on a pedestal

there was a man in Rome who lived on a pedestal he tried to make point too

I'm not going to learn calculus because newton did it on the sidelines when working on alchemy whilst a lapdog for the royal scientific blah :) .

I want to learn what makes sense . if quantum physics has to use doodles to explain itself then in my opinion enough said.

if a teacher does not understand don't listen to his confusion of a thought experiment for it will entangle your mind like him

the 20th century was and our economy presently is based on heat engines. rockets petrol oil fine yes but there is a limit too this madness. stop understanding teachers and overstand them . surely that is a point of a teacher . zen paradoxes are for goldfish. shrodinger and his cat . please!

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