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Resurrected theory solved: 50 year old physics conundrum buried


How glass mittens sound: researchers from the Constance College clear up a physics thriller by rediscovering a discarded concept.

Typically the knowledge is already there, simply misplaced. For almost fifty years, the peculiar vibrational habits of glass at low temperatures have puzzled physicists. Glass carries sound waves and vibrations in a different way than utterly completely different solids – it vibrates in a different way. Anyway, why?

And the way can the propagation of sound in glass be calculated appropriately? Two physicists from Constance, Matthias Fuchs and Florian Vogel, have now found the reply: They took an outdated mannequin, which was created round 20 years in the past and was rejected by the specialists on the time, and reworked it. His new method to outdated pondering has now been revealed in Physique Analysis Letters.

dampened vibrations

Those that transmit sound waves by way of glass and measure them very exactly might discover a vibration damping that’s absent in lots of solids. It has far-reaching penalties for the thermal properties of glass, equal to alternating warmth and warmth capabilities. The impression is well-known in physics, however till now there was no theoretical mannequin that might adequately describe it and supply the framework for tougher calculations of sound propagation in glass.

The glasses are messy strong. Not like crystalline solids, the particles that make up glass do not need to be endlessly organized. In most solids, the particles are virtually utterly aligned, like constructing blocks organized in an precise lattice. When a wave-like vibration is generated in such crystalline solids at low temperatures, the particles move by way of the vibration within the course of their undamped neighbors. The vibration flows in a uniform wave with out loss, similar to a wave in a stadium.

Dispersion impression on glass

In distinction, the glass particles shouldn’t be organized in a typical sample, however ought to have random positions with out strict order. The approaching oscillation waves needn’t proceed in a uniform sample. As an alternative, the vibrations arrive at random particle places and are carried in a corresponding random sample. The result’s that the uniform wave is damaged up and dispersed into quite a few smaller waves. This dispersion of the footprint causes damping. Physicist Lord Rayleigh used this mechanism of scattering daylight by irregularities within the environment to make clear the blue tint of the sky, which is why this impression is known as Rayleigh damping.

Rediscovery of a discarded mannequin

About 20 years in the past, physicists Marc Mezard, Giorgio Parisi (Nobel Prize in Physics 2021), Anthony Zee and their colleagues described these glass anomalies utilizing a dummy of oscillations in random positions known as the Euclidean Random Matrix (ERM) method. . A easy mannequin that was principally the reply, says Matthias Fuchs, a professor of maudlin pondering on condensed matter on the College of Konstanz. Nevertheless, the model nonetheless had some inconsistencies and because of this it was rejected by specialists and fell into oblivion.

Matthias Fuchs and his colleague Florian Vogel have as soon as once more taken up the outdated mannequin. They discovered selections for the open-ended questions that the science crew could not reply on the time, and reviewed the revised mannequin by glancing at its Feynman diagrams. These helpful graphs have been launched by Richard Feynman as a part of the concept of ​​quantum self-discipline and have revealed regularities inside scattered wave patterns.

The outcomes of Matthias Fuchs and Florian Vogel offered exact calculations of the sound propagation and damping impression inside the glass. “Mezard, Parisi and Zee have been simply of their insightful mannequin: harmonic oscillations in a messy sharpening make glass anomalies at low temperatures clear,” explains Fuchs.

The discovered dummy, nonetheless, is much from the excessive level of historical past: for us it’s the beginning line: we now have now discovered the proper dummy which we are going to now use for extra calculations, particularly for quantum mechanical outcomes, Matthias . says Fuchs.


The mysteries of glass and its distinctive low-temperature vibrational habits have lengthy intrigued scientists. Nevertheless, researchers from the Costanza College have gone one step additional by rediscovering and revising an outdated and discarded mannequin. They discovered that the cup dampens sound waves and vibrations in one other means from completely different solids attributable to its messy combination of particles. This damping impression, known as Rayleigh damping, happens as a result of the uniform wave of vibrations is dispersed into smaller waves. By reworking the out of date dummy and inspecting it by way of Feynman diagrams, the scientists have been in a position to precisely calculate the propagation of sound in glass and make clear its anomalies at low temperatures. This discovery is just the start, as researchers can now uncover additional computations, significantly related to the extremities of quantum mechanics in glass.

Questions commonly requested

What are the distinctive vibrational habits of glass at low temperatures?

Glass carries sound waves and vibrations in a different way than utterly completely different solids. It displays vibration damping that’s absent in different choices.

Why was it troublesome to calculate the propagation of sound in glass at low temperatures?

Glass is a messy fort with randomly organized particles, not like crystalline solids with incessantly organized particles. The random affiliation of the glass particles causes the approaching oscillation waves to disperse into smaller waves, which happens inside the damping impression. Till now, there was no theoretical mannequin that precisely describes this phenomenon and permits for sophistication calculations.

What’s Rayleigh Damping?

Rayleigh damping is the phenomenon by which a uniform wave of vibration breaks up and disperses into quite a few smaller waves because of an uneven combination of particles. This impression is called after the physicist Lord Rayleigh, who used an analogous mechanism to make clear the blue tint of the sky.

What’s the which means of the rediscovered mannequin?

The discovered phantom, initially discarded, affords applicable calculations of sound propagation and damping impression on glass. It serves as a place to begin for additional evaluations, significantly exploring the outcomes of quantum mechanics in glass.


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