Laws of Thermodynamics? More like suggestions!
This news feature, posted on Nature's website recently, discusses how various forms energy (heat, electricity, magnetism and light particularly) behave differently at the atomic scale. The laws of thermodynamics might not be breakable, but they can be bent! The following quote from the news feature demonstrates an example of how the standard laws of thermodynamics may, under special conditions, break down at the atomic scale.
Experiments are starting to pin down that quantum–classical boundary. Last year, for example, Schaetz and his colleagues showed that, under certain conditions, strings of five or fewer magnesium ions in a crystal do not reach and remain in thermal equilibrium with their surroundings like larger systems do.
In their test, each ion started in a high-energy state and its spin oscillated between two states corresponding to the direction of its magnetism — 'up' and 'down'. Standard thermodynamics predicts that such spin oscillations should die down as the ions cool by interacting with the other atoms in the crystal around them, just as hot coffee cools when its molecules collide with molecules in the colder surrounding air.
Such collisions transfer energy from the coffee molecules to the air molecules. A similar cooling mechanism is at play in the crystal, where quantized vibrations in the lattice called phonons carry heat away from the oscillating spins. Schaetz and his colleagues found that their small ion systems did stop oscillating, suggesting that they had cooled. But after a few milliseconds, the ions began oscillating vigorously again. This resurgence has a quantum origin, says Schaetz. Rather than dissipating away entirely, the phonons rebounded at the edges of the crystal and returned, in phase, to their source ions, reinstating the original spin oscillations.
So what impact does this have on technological developments? It demonstrates some of the ways in which as we try to miniaturize computer components further and further, the systems tend to no longer behave as expected. Instead of the thermal energy dissipating and staying away (as your coffee would eventually reach room temperature), these effects mean that the heat may be trapped, and eventually cause burn-out of the electronic components. However, the effect may also be used to process quantum information at higher temperatures - a major present hurdle to the realization of practical quantum computers.
Having been a theoretical discussion piece for the better part of 30 years, quantum effects on the laws of thermodynamics have lacked from experimental results, demonstrating such effects. The news feature discussed here showcases some recent experimental results which do just that.
Having been a theoretical discussion piece for the better part of 30 years, quantum effects on the laws of thermodynamics have lacked from experimental results, demonstrating such effects. The news feature discussed here showcases some recent experimental results which do just that.
Photo credit: https://www.nature.com/news/the-new-thermodynamics-how-quantum-physics-is-bending-the-rules-1.22937
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