3rd Law of Thermodynamics Unveiled: Revolutionary Quantum Formulation

Attaining the lowest possible temperature and erasing the data perfectly and completely, these two things might appear to not have any correlation and may seem unrelated, but they share a very strong connection. The quantum formulation for the 3rd law of thermodynamics has been discovered by researchers at TU Wien.

The lowest temperature that can be attained is called the temperature of absolute zero, which has a value of -273.15 degree Celsius. Unfortunately, however, this temperature is impossible to attain as objects can only get close to the value of absolute zero. This concept is widely known as the third law of thermodynamics.

The compatibility between the third law of thermodynamics with the principles of Quantum Physics has been recently explored by a group of researchers at TU Wien (Vienna). They were successful in devising a ‘Quantum Version’ of the third law of thermodynamics, which implies that attaining the temperature of Absolute Zero is possible theoretically. 

3rd Law of Thermodynamics: What it says?

However, it says that any viable method to achieve absolute zero requires three components: energy, time, and complexity. If any one of these components is available in infinite supply then the temperature of Absolute Zero can be achieved.

When Quantum Particles reach the temperature of absolute zero, their state is precisely known. They are guaranteed to be in the state with the lowest energy that is possible to achieve by them. When this happens the particles lose information about the state they were in before. Everything that has happened to the particle before it reached absolute zero is completely erased. Cooling and deleting information from particles, from a Quantum Physics point of view is closely related.

At this junction, two very important theories meet, i.e the information theory and thermodynamics. But they appear to be contradicting each other. Prof. Marcus Huber from the Atomic Institute of TU Wien explains that from information theory, we know the so-called Landauer Principle, which says that a very specific minimum amount of energy is required by the system to delete or erase one bit of information. 

Thermodynamics, however, says that to cool anything down to exactly the temperature of absolute zero an infinite amount of energy is needed. But if cooling and deleting information appear to be the same thing- how does that fit together?

The root of the problem lies in the fact that thermodynamics was formulated for classical objects in the 19th century, for steam engines, refrigerators, etc. At that time, people had no idea or knowledge about Quantum Physics. If we want to understand the thermodynamics of individual quantum particles then we have to first try to understand and analyze how quantum physics and thermodynamics interact and influence each other. This is what Marcus Huber and his team have done.

Marcus Huber said that they had quickly realized that it’s not necessary to use an infinite amount of energy to attain a temperature of absolute zero. He says it is also possible with finite energy but then you will need an infinite amount of time to attain absolute zero. Up to this point, the consideration to attain the temperature of absolute zero is still compatible with classical thermodynamics. But then the team came across an additional piece of information of crucial importance. Also Check: NASA to conduct 2 Super Pressure Balloon Tests

Marcus Huber says that they found quantum systems can be defined that allow absolute ground systems to be reached and attained even with finite time and finite energy and none of them had expected that. He says that these quantum systems have another very important property, which is that they are infinitely complex. 

This means that it requires infinitely precise control over infinitely many details of the Quantum System, then it would be possible to attain the temperature of absolute zero by a quantum particle with just finite time and finite energy. In practice, practically this is just as unattainable as achieving to provide infinite energy and infinite time.

Marcus Huber said that if you want to perfectly and completely erase information from a quantum computer and in the process of doing this transfer and send a QUBIT to a perfectly pure ground state, He says, then theoretically it would require an infinitely complex quantum computer that can control an infinite no of particles. 

In practice, perfection to such an extent is not easy, no machine is ever that perfect. It is enough for a Quantum Computer to perform its operations fairly well. So the new results are not an obstruction in principle to the development of Quantum Computers. 

Temperature plays an important and key role in the practical application of Quantum Computers, the higher the temperature is the easier it is for Quantum States to show errors, break, and be unusable for any technical use. 

Marcus Huber said that this is precisely why it is so important to better understand the connection and the compatibility between Thermodynamics and Quantum Theory. He adds that there has been a lot of progress in this area at the moment and it is slowly becoming possible to see how these two important parts and fields of physics intertwine.