Can we violate the second law of thermodynamics? This question nagging for the Multivac computer in the news of Isaac Asimov The last question may have a positive response according researchers at the Weizmann Institute in Israel. It would suffice to bring the magic formulas of quantum mechanics. 

The second law of thermodynamics is one of the most solid pillars of physics. It is on it that Albert Einstein relied to prove the existence of quanta of light let through to him that Stephen Hawking discovered the radiation of black holes. This principle has an unpleasant, as was well understood one of its discoverers, Rudolf Clausius. Applied to an isolated system, as is perhaps the universe, it leads him to the dead heat, a total and irreversible decay. 

This great principle may be stated in a surprisingly simple: "The heat does not pass spontaneously from a cold body to a warm body." It is therefore a principle of evolution which establishes the meaning of the transformations of nature. It only translate a set of simple observations. Thus, an ice cube thrown into a glass of warm water not only cools and a broken cup does not glue itself. 

We know that in the quantum world nothing is happening as we suggested in our intuition. Particles sometimes behave like waves and vice versa the walls high and thick are crossed by tunneling. Nothing is completely determined, the evolution of laws concerning the probability of observing a given value of a physical quantity. 

However, the laws of quantum mechanics, which are ultimately the basis of the classical world which operates the second law of thermodynamics. It can therefore legitimately wonder if it is not an approximation, albeit prodigiously effective, but that laws of quantum mechanics can violate when they appear on the atomic level. 

So far, this crime against second principle has never been observed. But the situation could change after the publication of a theory in Nature Kurizki by Gershon, and Noam Erez Goren Gordon of the Weizmann Institute, in collaboration with Mathias Nest at the University of Potsdam, Germany. 

These researchers make a surprising contribution to quantum mechanics known as the Zeno effect. What is it? 

In quantum mechanics, the observer, whether a human being or a measuring instrument, plays a fundamental role. According to the standard interpretation of quantum theory, one can not speak of the actual existence of certain attributes of a quantum system without involving the act of measurement for the observer. In itself, a quantum particle of matter does not exist as an object located on a constant in space and in time. It is the interaction with a classical physical system in a place and time given, which may lead it to manifest itself as a classical object like a billiard ball. 

A quantum system affected by observation 

A quantum system, like a atom coupled to an electromagnetic field or an elementary particle coupled with weak interactions, can in the first case is energized to emit photons, or in the second, other particles such as muons and neutrinos she is a pawn. The coupling is a field in some way as a measure and force the system to evolve. 

The Zeno effect is a reverse effect where the repeated observation of a quantum system by a measuring block its development! In both previous examples, after watching an atom or a pawn to detect the emissions of particulates, it prevents them from doing so! 

In the case examined by four researchers, we consider a quantum system exchanging heat with a reservoir of energy. It turns out that according to their equations obeying the laws of quantum mechanics, according to the frequency of observations to determine whether there is heat, it can actually occur, but in a way violating the second principle ! More specifically, this is one possible interpretation of the consequences of these equations. 

The researchers are cautious, however. After all, at the time, Maxwell believed also to have found a way around the second principle with his demon. Deeper analysis of Leo Zsilard showed thereafter that he was not. 

It seems much safer than the process theorized by researchers should be able to control at will the very rapid exchange of heat between the atomic and molecular systems, a possibility which certainly will have applications in nanotechnology.