Absolute zero and complex systems
Complex systems can emerge from interactions between many quantum particles. And because of this complexity, it is theoretically possible to attain absolute zero.
Although they may seem unrelated, perfect data erasure and reaching the lowest temperature have a lot in common. The third rule of thermodynamics has a quantum version, according to researchers at TU Wien.
The lowest temperature imaginable, absolute zero, has a temperature of -273.15 degrees Celsius. However, since things can only approach this temperature, it is not possible to attain it. The third law of thermodynamics is the term used to describe this idea.
Recently, a team of scientists from TU Wien, looked into whether the third rule of thermodynamics and the fundamentals of quantum physics are comparable.
They were able to create a “quantum version” of this rule, which asserts that it is theoretically feasible to attain absolute zero. But any practical approach to accomplishing this needs three things: complexity, energy, and time.
Only if one of these elements is infinitely abundant can absolute zero be reached.
https://www.eurekalert.org/news-releases/984985
The precise state of a quantum particle at absolute zero is known: it is always the one with the lowest energy. The information about their previous condition is therefore lost from the particles.
The particle has completely forgotten everything that could have occurred to it in the past. Thus, from the perspective of quantum physics, cooling and information deletion are strongly connected.
At this time, thermodynamics and information theory – two significant physical theories- intersect. But the two seem to be at odds with one another. We are aware of the so called Landauer principle thanks to information theory.
Prof. Marcus Huber from the Atomic Institute at TU Wien explains that it states that a very particular minimum quantity of energy is needed to erase one piece of information.
However, according to thermodynamics, nothing can be cooled all the way down to absolute zero without requiring an unlimited supply of energy. But how can it work if erasing data and reaching absolute zero are the same thing?
Complexity, time and energy
Since thermodynamics was developed in the 19th century for classical devices like steam engines, freezers, and blazing coal, this issue has its roots in that age.
People were unaware of quantum theory at the time. Marcus Huber and his colleagues examined the interactions between thermodynamics and quantum physics in order to better understand the thermodynamics of specific particles.
Marcus Huber explains, “We rapidly realised that you don’t always need to utilise infinite energy to get absolute zero. With limited energy, it is still conceivable, but it would take an indefinite amount of time.
The concerns are still consistent with classical thermodynamic as we know it from textbooks up to this point. But later, the group discovered a further, very significant detail:
No one had anticipated it, but we discovered that quantum systems may be constructed that allow the absolute ground state to be attained even at finite energy and infinite time.
The fact that these unique quantum systems are indefinitely complex is another significant characteristic. Then you could chill a quantum item to absolute zero infinite time with finite energy, but you would require infinitely precise control over infinitely many features of the quantum system.
Naturally, in reality, this is as impossible to achieve as indefinitely high energy or endlessly long time.
Deleting information from a quantum computer
According to Marcus Huber, in theory, you would need an indefinitely sophisticated quantum computer that can flawlessly manage an unlimited number of particles if you wanted to precisely delete quantum information in a quantum computer and move a qubit to a perfectly pure ground state in the process.
However as no machine is ever flawless, perfection is not essential in practice. It suffices for a quantum computer to function quite well. Therefore, the new findings do not in theory, pose a barrier to the creation of quantum computers.
Since quantum states are more easily broken and rendered useless for any technological purpose at higher temperatures, temperature is a crucial factor in today’s practical uses of quantum technology.
Marcus Huber argues that this is the very reason it is crucial to comprehend how quantum theory and thermodynamics are related. There has been a lot of fascinating development lately in this field. It is becoming clear how these two significant physics components interact.
Source: eurekalert
