The thermodynamic argument is, in my opinion, absolutely rock solid. There is no way to extract useful work from the vacuum, basically because there is no bath into which the fluctuations can be. In general, the idea of extracting useful work from the ZPE is typically the stuff of junk science and useless patent proposals that are intellectually on a par with perpetual motion machines (see for example the commentary and related ones at Bob Parks excellent "What's New" service: http://bobpark.physics.umd.edu/WN02/wn050302.html, Item 3, or search for 'Zero Point Energy' on his website).

However there are some interesting ideas out there from exploiting ZPE (which I confess I haven't explored them seriously) that may not be wrong, and that take advantage of the change in the vacuum properties between environments. You might be interested in this paper: "Extracting electrical energy from the vacuum by cohesion of charged foliated conductors" Robert L. Forward, Physical Review B 30, 1700–1702 (1984). The reason why this does not fall foul of the thermodynamic limitations is that this is essentially a battery where you do work on the vacuum, and then that work can be later extracted (no free energy, finite efficiency etc.).

I can't tell you how useful this concept is, but a brief glance shows 19 citations, where the latest two didn't say that the concept had been refuted!

The fluctuations generally can't be used for the extraction of energy either, and in fact there are some nice treatments where these approaches are used in explorations (and even derivations) of Maxwell's daemon. Related to this are treatments of quantum versions of Maxwell's daemon and quantum ratchets.

So in short - the study of zero point fluctuations is still very active, and is being supported by beautiful experiments. There's a lot of good science still to be done and undoubtedly new applications. But I very much doubt any form of energy harvesting from the vacuum will ever be found, where my level of doubt on this topic is roughly equal to my level of doubt of faster than light travel.

The question is how do you then deal with the 2nd law of thermodynamics to extract zero-point energy ?

For energy to be recoverable or harvestable, you absolutely need a cold source - you can have all the vacuum or zero point energy you want, potentially trillions upon trillions of tetrawatts, if you do not have a cold source to transfer energy towards it won't do you any good.

Now you could try in theory to extract fluctuating energy spikes from quantum fluctuations - although I'm not sure about the engineering behind that - but how would this provide much measurable energy ?

Besides, the cold source itself would be subject to quantum fluctuations and I would think that statistically, such energy recovery would be extremely hard to achieve. I understand self-organization, but how can this be harnessed to bypass the 2nd law?

I'm interested in your answers?

Dear Cris, Your arguments I accept. The zero-point energyis the lowest possible energy that a quantum mechanical physical system may have. And as you mention in this system due to thermodynamic law is not possible to find colder body.

But what about other systems. Or as you ansvered- what about fluctuations. Casimir force is real phenomena. There are electronic measuring systems effected by zaro point fluctuations. NASA spend resources to study this phenomenon-you mentioned that this energy is too much and if we learn to harvest???

Nevertheless I continue to be sceptical, but am also interesting from research!

The thermodynamic argument is, in my opinion, absolutely rock solid. There is no way to extract useful work from the vacuum, basically because there is no bath into which the fluctuations can be. In general, the idea of extracting useful work from the ZPE is typically the stuff of junk science and useless patent proposals that are intellectually on a par with perpetual motion machines (see for example the commentary and related ones at Bob Parks excellent "What's New" service: http://bobpark.physics.umd.edu/WN02/wn050302.html, Item 3, or search for 'Zero Point Energy' on his website).

However there are some interesting ideas out there from exploiting ZPE (which I confess I haven't explored them seriously) that may not be wrong, and that take advantage of the change in the vacuum properties between environments. You might be interested in this paper: "Extracting electrical energy from the vacuum by cohesion of charged foliated conductors" Robert L. Forward, Physical Review B 30, 1700–1702 (1984). The reason why this does not fall foul of the thermodynamic limitations is that this is essentially a battery where you do work on the vacuum, and then that work can be later extracted (no free energy, finite efficiency etc.).

I can't tell you how useful this concept is, but a brief glance shows 19 citations, where the latest two didn't say that the concept had been refuted!

The fluctuations generally can't be used for the extraction of energy either, and in fact there are some nice treatments where these approaches are used in explorations (and even derivations) of Maxwell's daemon. Related to this are treatments of quantum versions of Maxwell's daemon and quantum ratchets.

So in short - the study of zero point fluctuations is still very active, and is being supported by beautiful experiments. There's a lot of good science still to be done and undoubtedly new applications. But I very much doubt any form of energy harvesting from the vacuum will ever be found, where my level of doubt on this topic is roughly equal to my level of doubt of faster than light travel.

Back in 1996, I extensively reviewed this very question:

Https://www.researchgate.net/publication/233754109_quantum_vacuum_fluctuations_zero_point_energy_and_the_question_of_observable_noise

Andy is right that you cannot get *useful* energy out of the vacuum field. You can actually get energy out of it (if you read the above paper) but it is not useful. You only get out what you put in, in the first place,

One clarification about Andy's statement that says: "fluctuations generally can't be used for the extraction of energy either...." ...this of course is only true in equilibrium. When you are out of equilibrium you can harness fluctuations. The whole science of Brownian ratchets is all about harnessing out-of-equilibrium fluctuations.

If one is to believe the Big Bang model of the universe that matter came of out empty space due to vacuum fluctuations, I guess that is an out-of-equilibrium scenario. But that model is only a hypothesis and I have concerns about it :-)

Conference Paper QUANTUM VACUUM FLUCTUATIONS, ZERO POINT ENERGY AND THE QUEST...

Dear Derek

I am very much interested in the something from nothing universe argument. You have already expressed that this scenario is an out of equillibrium one, you also mentioned you have other concerns. Could you please share those concerns with us because I find this argument ( something from nothing universe) difficult to comprehend!

The idea that the universe began due to vacuum fluctuations is one theory, and not one we are obliged to accept :-) There are obvious questions: (i) where does the asymmetry come from that starts the process?, (ii) what happens to the 2nd law?, and (iii) from an information theory point of view is information being created or destroyed? And what does it mean?

Cosmologists who believe this theory have answers to these questions, but they are answers that have not made sufficient impression on me that I have cared to retain them in my memory.

I got the message! Thank you.

Derek,

The quantum fluctuation scenario for the Big Bang is only one of several ways a Big Bang can happen, which was first championed by Trion. There are many other scenarios (brane collision, etc.), and all of them can be valid - there is no reason to believe that only one Big Bag ever happened or ever will happen.

The Trion scenario is in essence very simple, but throws off questions. The scenario is that in Heisenberg's equation, delta time (duration of existence of a virtual particle) and the mass of the object are orthogonal attributes. If for whatever reason a virtual object arising out of the quantum foam were so massive that its corresponding Heisenberg conjugate time would be shorter than the reigning quantum of time, then the mass would become real because the quantum delta time would be incompressible, and longer than the conjugate delta time: the only issue would be BANG, the mass becomes real, so that Heisenberg is not violated.

Of course, the conditions prevalent in the original quantum foam have to be analysed; also, a question arises of the statistics that govern the emergence of virtual objects within a quantum foam, i.e. statistics such as what is the frequency, and the frequency distribution, of attributes of the virtual objects (mass, etc.)

I had posted a question on this (whether there was any conceivable way of apprehending the statistics of virtual objects arising from quantum foams), which was promptly deleted by User Care who deemed the question 'unscientific'. Go figure ....

Dear all! Thank you for interesting ansvers. I must learn more and study your questions and arguments, but wish appointed the Derek argument, that important is an out of equilibrium system! Also-there not arguments against measurability of the ZP fluctuations.The sentence "Fluctuations out of equilibrium are measurable" focused my attention.

I suppose, that all fluctuations are out of equilibrium! Am I right?

@Georgi. When you say "all fluctuations are out of equilibrium," it depends what you mean. Temperature is a macroscopic concept and you can define the temperature of the chair I am sitting on. But it is difficult to assign a meaningful temperature to one atom that is fluctuating inside my chair. My chair is on average in thermal equilibrium with its surroundings, but the individual atoms are fluctuating around that equilibrium.

So when I was talking about "equilibrium fluctuations" it was shorthand for talking about the equilibrium of the macroscopic source of fluctuations.

For example, imagine a resistor is the source of our noise or fluctuations. We know the noise power coming out of that resistor is 4kTB, where T is the temperature. Any "demon" I invent to try to harness this power into useful work will never work. Why? Because of these two cases: (i) if the demon is also at the temperature T then it will also have its own noise power of 4kTB and thus there will be detailed balance on average. I might get "useful" work for one microsecond, but in the next microsecond I will have no control over which direction the work is applied. So on average over time, no useful work has been done. (ii) if I now cool the demon to a lower temperature than the resistor, I now can get useful work done! However, that is at the expense of the energy I needed to create the temperature differential in the first place. And as no "engine" is 100% efficient, I get less energy out than I put in. So I might have a "useful" engine here, but I do not have a useful generator of energy.

A car engine is a useful thing because it gives us transportation in return for burning gasoline. However, it never outputs more work than the energy content in the petrol. I mention this as an example that things are still "useful" even though they don't give net energy gain.

If you want to read more about electrical versions of Maxwell's demon, I recommend this interesting paper:

http://www.plosone.org/article/fetchObjectAttachment.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0046800&representation=PDF

Thank you Derek! I read really interesting paper.

Nevertheless I am continuing to thing about the fluctuations of physical vacuum that manifest its existence in Casimir effect, as example.

You explain us about the thermodynamic reasons to have not energy transfer between two solid samples with equal temperatures. But if we look to a gas. On the wall of pot including it have presure equal to nkT=p and this gas, due to fluctoations of the molecules could produce some work. Here 2-nd law is not applicable?

Imagine molecules of gas hitting a microscopic propeller. If this propeller is connected to a ratchet mechanism the propeller is forced to go in one direction, and so it seems you are getting useful work out of the gas. But this is not correct. The reality is that, if the ratchet itself is at the same temperature T as the propeller, the ratchet itself will fluctuate and occasionally allow the propeller to go the wrong way.

We show in this paper:

http://www.eleceng.adelaide.edu.au/personal/dabbott/conference/UPN_abbott1999a.pdf

...that, at equilibrium, the propeller will rotate equally in both directions on average, so no useful work is done. This is called detailed balance.

If you cool the ratchet you can get useful work, but the cooling is costing you energy. So you don't win again.

Notice at thermal equilibrium the wheel does turn, and so it seems you are getting some useful work temporarily but then the wheel goes the wrong way and you have no control. So on average there is no useful work. But you can imagine you are getting useful work for a very short time.

Let us imagine there are tiny creatures who's lifespans are much shorter than the timescales in which the propeller rotates. These creatures live for a time much shorter than the time it takes to propeller to rotate one way, so then the work done looks "useful." But to our timescale it is not useful.

So we may wonder if there are some processes in the universe that satisfy the Second Law on a very long timescale, but on our short human timescale looks useful to us? I suppose an example of this is the Sun. To us the Sun provides us with useful work and our lifespans are much shorter than the Sun. But on the scale of the lifetime of the universe, the creation of the Sun and then its death is a small fluctuation. But to us it was useful.

Not if we see the ZPE as random fluctuation of fields and particles, as the consequence of Heisenberg's uncertainty principle. I suppose ZPE can be harvested if we could enhance our understanding of ZPE beyond the current physics paradigm, that is founded on Einstein's speed barrier and Heisenberg's uncertainty. The new paradigm of physics must be beyond Lorentz symmetry and gauge symmetry. Quantum statistics and statistical physics in general imply that harvesting/using zpe is not possible, since this means that the entropy of ZPE can be lowered, and it already has the lowest entropy. A usable source of energy is not totally random/chaotic, it has order/structure on 'our' scale of magnitude. The key question: is ZPE truly random or does it have a pattern not yet discovered, such that its entropy can be lowered? Solar energy can be used, it has 'structure', although the sun is chaotic, its light wave output is not totally random. I believe the ZPE has a 'source' and a 'pattern', after all ;-), but be cautious with ZPE patent claims, since our understanding of ZPE is too limited.

The gaseous aether substrate has an immense pressure (some 10^36 N/m^2) and that is the source of all the energy in all the orbital systems and mass ...

As for the principles related to the "free energy", I added some rough English translation to the originally Russian booklet of Atsukovsky here

https://miteam.mi.sanu.ac.rs/asset/JyiKp5Te5RrzDcibX

Natural and/or induced aether structuring is actually (localized) decrease in Entropy, which becomes compensated from the supplies generated in high-leve structures, as galactic centers (so called "black holes", w/ Hawking radiation ... :).