Entropy Wins QM Challenges

The 2nd Law of Thermodynamics
still tolerates no exceptions

 

The First and Second Laws of Thermodynamics are the best examples of laws of nature. Formulated by 19th century physicists, including James Joule and Lord Kelvin, these two laws have no exceptions even though they were formalized before the 20th century revolutions of relativity and quantum mechanics. According to the First Law, no mass-energy can be created or destroyed. The Second Law guarantees that all spontaneous processes in a closed system lose available energy: they gain entropy, a measure of disorder or randomness of a system. These laws forbid spontaneous creation and perpetual motion machines. The Second Law is called the “arrow of time” because we know by experience that tornadoes do not run backwards to build cities or airplanes.

The “law” of evolution, however, contradicts both of those laws: cosmic evolution claims the entire universe came from nothing, and biological evolution claims that organisms progress from simple to complex. Darwinians claim increasing “fitness” (whatever that is) is not a violation of the Second Law (hence 2TD) because the earth is an open system, receiving energy from the sun. Energy alone, however, cannot rescue Darwinism. As Henry Morris used to say, a bull in a china shop adds energy but does not create order, nor does pouring gasoline on top of a car and lighting a match. Energy must be converted from one form to another (e.g., chemical to kinetic) by a mechanism that is directed toward a goal (e.g., driving a car up hill with an engine). Humans can design things that do that, like cars and rockets, to reduce entropy locally. The overall entropy of the “universe” (all the energy of the system), however, always increases.

Several new articles push quantum process toward the limits of thermodynamics. Do they win?

Rethinking Carnot: Scientists overcome traditional power-efficiency trade-off (Phys.org, 31 Jan 2025). This article discusses the idealized “Carnot engine” that describes the maximum work that can be extracted from a heat engine, i.e., a system extracting work from a hot reservoir transitioning to a cold “sink” (ending state). This idealized engine model was important to engineers attempting to improve the efficiency of steam engines. The wording in this article may be unfamiliar to most readers, but it claims that the Carnot limit can be exceeded in quantum systems:

Challenging centuries-old assumptions about thermodynamics, a new study published in Physical Review Letters has shown that it is theoretically possible to design a heat engine that achieves maximum power output while approaching Carnot efficiency.

If it is designed, however, it is receiving the input of intelligent design, as in the case of rockets and cars. The article claims it is “theoretically possible” to design such a system. “The next step would be to find practical heat engines with these properties, which is a challenge,” they say. Let’s see them do it. When all the accounting is done for the energy involved, one can be confident that 2TD will not be violated. The article admits, “In reality, real heat engines are not reversible and lose energy in the form of heat.” That heat represents the entropy: energy no longer available to do work.

Of interest is their illustration of biochemical systems that exceed Carnot efficiency, like the ATP synthase motor, and protein folding processes, which operate at the quantum level. Those are prime examples in real life used by intelligent design advocates to illustrate the wisdom and power of God. Spontaneous chemicals in warm little ponds could never generate systems like that which, while not violating the law of entropy, push the limits of physical possibility to near 100% efficiency.

The paper in Physical Review Letters is behind a paywall, but the earlier preprint is available on arXiv. It appears that the authors’ model is theoretical only and not realistic to construct. Even if it were, it would not be superior to the molecular machines at work in our living cells.

Even Quantum Physics Obeys the Law of Entropy (TU Wien, 29 Jan 2025). This press release discusses the relationship between quantum mechanics (QM) and thermodynamics. Even with all its weirdness, QM obeys the law of entropy, despite claims of some to the contrary.

It is one of the most important laws of nature that we know: The famous second law of thermodynamics says that the world gets more and more disordered, when random chance is at play. Or, to put it more precisely: That entropy must increase in every closed system. Ordered structures lose their order, regular ice crystals turn into water, porcelain vases are broken up into shards. At first glance, however, quantum physics does not really seem to adhere to this rule: Mathematically speaking, entropy in quantum systems always remains the same.

A research team at TU Wien has now taken a closer look at this apparent contradiction and has been able to show: It depends on what kind of entropy you look at. If you define the concept of entropy in a way that it compatible with the basic ideas of quantum physics, then there is no longer any contradiction between quantum physics and thermodynamics. Entropy also increases in initially ordered quantum systems until it reaches a final state of disorder.

Those interested in this debate will enjoy reading how “quantum disorder increases after all” when definitions are considered and all the accounting of energy in the system is done properly.

“This shows us that the second law of thermodynamics is also true in a quantum system that is completely isolated from its environment. You just have to ask the right questions and use a suitable definition of entropy,” says Marcus Huber.

A symphony in quantum (University of Chicago, 10 Feb 2025). This press release describes a working design for a macroscopic acoustic system involving two resonators that take advantage of “entanglement”— a quantum property in which knowing the state of one body appears to “dictate” the state of another entangled body, even if the two are physically separated.

“A lot of research groups have demonstrated that they can entangle very, very small things down to the single electron. But here we can demonstrate entanglement between two massive objects,” said co-first author Ming-Han Chou, a former UChicago PME and Physics doctoral researcher now at the Amazon Web Services Center of Quantum Computing. “The second thing we demonstrate in this research is that our platform is scalable. If you can imagine building a big quantum processor, our platform would be like a unit cell within that.”

The entanglement isn’t between the molecules, atoms or any other particles that make up the resonators, but between the “phonons” that occupy the resonators. These are the nanoscale mechanical vibrations that, were there ears small enough to hear them, would be considered sound.

The scientists are optimistic that their work could lead to advances in quantum technology. As interesting as their work is, it does not bear on the question of whether QM violates 2TD.

No quantum exorcism for Maxwell’s demon (but it doesn’t need one) (Nagoya University, 10 Feb 2025). “Maxwell’s Demon” is a thought experiment conceived by Christian physicist James Clerk Maxwell in the 19th century. It was a theoretical way to violate 2TD. According to 2TD, hot particles in a warm room will always migrate to a cold room through an opening, not the other way around. But if a machine or mind (a “demon”—not Maxwell’s term) sorted the molecules passing through the opening, it could reverse the spontaneous energy flow, making the hot room hotter.

Many theoreticians have discussed this possibility and concluded it is not a violation of 2TD, because the energy used by the demon would increase the entropy of the system (21 Sept 2018). Some of our molecular machines, like those in our muscles, actually perform like this theoretical demon but they do not violate the law of entropy (see 30 Aug 2023).

Eight years ago, some physicists were holding out hope that violations of 2TD might be discovered in QM processes (22 July 2017). In this current announcement, Japanese scientists consider QM and 2TD to be independent theories. Could QM violate 2TD? They say no, even if QM can “approach” the theoretical limits:

In a groundbreaking discovery, researchers from Nagoya University in Japan and the Slovak Academy of Sciences have unveiled new insights into the interplay between quantum theory and thermodynamics. The team demonstrated that while quantum theory does not inherently forbid violations of the second law of thermodynamics, quantum processes may be implemented without actually breaching the law. This discovery, published in npj Quantum Information, highlights a harmonious coexistence between the two fields, despite their logical independence. Their findings open up new avenues for understanding the thermodynamic boundaries of quantum technologies, such as quantum computing and nanoscale engines.

The press release claims a QM exception to 2TD, but it is only theoretical and not practical.

“One thing we show in this paper is that quantum theory is really logically independent of the second law of thermodynamics. That is, it can violate the law simply because it does not ‘know’ about it at all,” Francesco Buscemi explained. “And yet—and this is just as remarkable—any quantum process can be realized without violating the second law of thermodynamics. This can be done by adding more systems until the thermodynamic balance is restored.” The implications of this study extend beyond theoretical physics.

Again, though, they are only speculating with mathematical models. Let them try to build a quantum perpetual motion machine. When all the accounting is done, 2TD will win. See also discussions about Maxwell’s Demon at Evolution News, some by CEH editor David Coppedge (8 Dec 2016, 29 April 2015).

Why even physicists still don’t understand quantum theory 100 years on (Nature, 3 Feb 2025). Don’t think that QM poses a threat to 2TD. Nature admits that even 100 years after QM theory was formulated, physicists do not understand it. This essay by Sean Carroll opens up a can of worms. What is meant by reality? And what is the role of science: to understand and explain, or just to take advantage of findings that appear useful?

Attempts to resolve this tension have proliferated, with no clear consensus in sight. Indeed, significant disagreement lingers around the most central question we can think of: is the quantum wavefunction supposed to represent reality, or is it just a tool we use to calculate the probability of experimental outcomes? This issue fundamentally divided Einstein and the Danish physicist Niels Bohr in famous debates they had over decades about the meaning of quantum mechanics. Einstein, like Schrödinger, was a thoroughgoing realist: he wanted his theories to describe something we might recognize as physical reality. Bohr, along with Heisenberg, was willing to forgo any talk about what was ‘really happening’, focusing instead on making predictions for what will happen when something is measured.

For a deeper understanding of the tension between realists and pragmatists, consider the Teaching Company course “Science Wars: What Scientists Know and How They Know It” by Dr Steven L. Goldman.

We have recommended this course before, but our readers should be aware Goldman, a colleague of Michael Behe at Lehigh University, is a critic of intelligent design and creation. Nevertheless, he has a knack for debunking the myth of scientists’ ability to explain things. With critical thinking skills intact, listeners will come away with a nuanced understanding of the oversold pretensions of scientists representing themselves as the supreme knowers of our culture.