Quantum Physics And Thermodynamics: Explaining The Thermodynamic Laws At Atomic And Sub-Atomic Levels

Quantum thermodynamics is a contemporary branch of science that involves the integration of concepts and laws of quantum physics and thermodynamics. Basically, what it does is to explain the thermodynamic perspectives of various systems at quantum level. Doing so will help in the development of nanoscale electronic instruments and "atom-sized machines."

Thermodynamics, the science of heat and entropy, is ages old, and textbooks still teach the laws of thermodynamics that were originally proposed in the 19th and 20th centuries. However, in these two centuries, physics has made immense progress, and physicists have made commendable efforts in understanding and implicating the basic laws of physics into practical applications. These are prominently in the field of electronic devices and nanotechnology.

Now, the question that prevails is whether the same thermodynamic laws that are applicable for large-scale systems stand true for nanoparticles or a new set of laws needs to be framed. These issues were discussed at the Fifth Quantum Thermodynamics Conference that was recently held in Oxford, U.K.

Davide Castelvecchi recently has an article published in Nature regarding on the same topic. The article highlighted that the laws of thermodynamics are many times "paradoxical," especially the second law of thermodynamics. The second law states that the total entropy of isolated systems can only increase, and the increase in entropy or the production of disorder is irreversible in nature. This contradicts the laws of mechanics, according to which, "all processes can be reversed."

Some other physicists believe the statistical mechanics model of physics helps in calculating heat and entropy of systems. However, the values obtained largely depend on the information available with the researchers and the approach followed. Furthermore, it has also been proposed that sub-atomic quantum systems reach equilibrium, and the ability of the sub-atomic particles to remain in quantum state can be harnessed for doing mechanical work.

On the other hand, the third law of  thermodynamics states that the entropy of a system at absolute zero equals zero, i.e., it is almost impossible to cool down an object to absolute zero. The Nature Communications journal published another article this month that explained quantum mechanics in relation to the third law.

The article written by Lluis Masanes and Jonathan Oppenheim from the University College London proposed that the rate of heat extraction from an object are defined by the laws of quantum mechanics. The calculations made by the authors indicated that it will take infinity for an object to reach absolute zero temperature. The article thus substantiated the third law of thermodynamics at a quantum level.

It is evident that physicists are divided on their perceptions of quantum thermodynamics and its applicability. Though full of controversies, still the field is growing at an unprecedented rate, and the real time practical applications of the same will be realized soon.