Happy #QuantumDay to all who celebrate!
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Happy #QuantumDay to all who celebrate!
Max Planck presented work on blackbody radiation to the German Physical Society #OTD in 1900.
His novel “quantum hypothesis” suggested that matter should be treated as it it emits and absorbs light with frequency f only in discrete chunks of energy E=hf.
Image: AIP
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Happy #QuantumDay to all who celebrate!
Max Planck presented work on blackbody radiation to the German Physical Society #OTD in 1900.
His novel “quantum hypothesis” suggested that matter should be treated as it it emits and absorbs light with frequency f only in discrete chunks of energy E=hf.
Image: AIP
Planck’s quantum hypothesis would revolutionize physics, but he initially thought it wasn’t real.
He suspected that the interaction of matter and radiation was tremendously complicated but still governed by the physics known at the time — what we now call “classical physics.”
Invoking quanta of radiation to derive the blackbody emission spectrum was, it seemed to Planck, just a mathematical trick that somehow encapsulated all that complication.
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Planck’s quantum hypothesis would revolutionize physics, but he initially thought it wasn’t real.
He suspected that the interaction of matter and radiation was tremendously complicated but still governed by the physics known at the time — what we now call “classical physics.”
Invoking quanta of radiation to derive the blackbody emission spectrum was, it seemed to Planck, just a mathematical trick that somehow encapsulated all that complication.
If so, it was a trick that *worked*.
Previous efforts to derive the blackbody emission spectrum using classical physics gave nonsensical results at high frequencies. Replace continuous emission with discrete quanta and things work out perfectly.
Evidence for the reality of quanta began with Einstein’s explanation of the photoelectric effect in 1905. The proposal that radiation of frequency f exists only in discrete chunks of energy E=hf was the first result of Einstein’s “Miracle Year.”
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If so, it was a trick that *worked*.
Previous efforts to derive the blackbody emission spectrum using classical physics gave nonsensical results at high frequencies. Replace continuous emission with discrete quanta and things work out perfectly.
Evidence for the reality of quanta began with Einstein’s explanation of the photoelectric effect in 1905. The proposal that radiation of frequency f exists only in discrete chunks of energy E=hf was the first result of Einstein’s “Miracle Year.”
Many physicists remained skeptical. But Arthur Compton’s 1923 explanation of X-rays scattering off electrons was near-incontrovertible evidence that quanta were real.
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Many physicists remained skeptical. But Arthur Compton’s 1923 explanation of X-rays scattering off electrons was near-incontrovertible evidence that quanta were real.
Here's a great APS Landmarks entry where you can read more about Compton Scattering and the reality of photons.
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Here's a great APS Landmarks entry where you can read more about Compton Scattering and the reality of photons.
This sequence of events was a not uncommon narrative in the transformative years of late 19th and early 20th century physics. It would go something like this:
1. An experimental result doesn’t make sense
2. A physicist proposes a radical solution.
3. The solution seems too weird to be real. Everyone assumes it must be a convenient "trick."
4. Eventually, everyone realizes it wasn't a trick, and reality is in fact weirder than they expected.
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This sequence of events was a not uncommon narrative in the transformative years of late 19th and early 20th century physics. It would go something like this:
1. An experimental result doesn’t make sense
2. A physicist proposes a radical solution.
3. The solution seems too weird to be real. Everyone assumes it must be a convenient "trick."
4. Eventually, everyone realizes it wasn't a trick, and reality is in fact weirder than they expected.
Planck’s hypothesis was in fact a deep statement about the nature of Nature. Electromagnetic adiation of frequency f comes in discrete chunks of energy E=hf. It's not an artifact of a complicated interaction with matter.
Nowadays we refer to the proportionality constant h as "Planck's constant." In the SI system it takes the value h=6.626 x 10⁻³⁴ kg*m²/s, or 4.136 x 10⁻¹⁵ eV*s.
As far as we can tell, h is a fundamental constant that is hardwired into our Universe.
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Planck’s hypothesis was in fact a deep statement about the nature of Nature. Electromagnetic adiation of frequency f comes in discrete chunks of energy E=hf. It's not an artifact of a complicated interaction with matter.
Nowadays we refer to the proportionality constant h as "Planck's constant." In the SI system it takes the value h=6.626 x 10⁻³⁴ kg*m²/s, or 4.136 x 10⁻¹⁵ eV*s.
As far as we can tell, h is a fundamental constant that is hardwired into our Universe.
The results of Planck’s December 14th lecture were submitted to Annalen der Physik a few weeks later, on January 7th, and published not long after that.
You can see the original (in German) here:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/andp.19013090310An English translation of Planck’s paper, taken from Dirk ter Haar’s “The Old Quantum Theory,” is available here:
https://web.archive.org/web/20230529024105/http://hermes.ffn.ub.es/luisnavarro/nuevo_maletin/Planck%20(1900),%20Distribution%20Law.pdf -
The results of Planck’s December 14th lecture were submitted to Annalen der Physik a few weeks later, on January 7th, and published not long after that.
You can see the original (in German) here:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/andp.19013090310An English translation of Planck’s paper, taken from Dirk ter Haar’s “The Old Quantum Theory,” is available here:
https://web.archive.org/web/20230529024105/http://hermes.ffn.ub.es/luisnavarro/nuevo_maletin/Planck%20(1900),%20Distribution%20Law.pdfSomething that isn’t as widely known is that “h” is not the only fundamental constant that was introduced during Planck’s presentation to the German Physical Society #OTD in 1900!
Planck was investigating emission and absorption by blackbodies, so he needed a way to relate energies and temperatures. Thus, he had to introduce what we now refer to as “Boltzmann’s constant.”
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Something that isn’t as widely known is that “h” is not the only fundamental constant that was introduced during Planck’s presentation to the German Physical Society #OTD in 1900!
Planck was investigating emission and absorption by blackbodies, so he needed a way to relate energies and temperatures. Thus, he had to introduce what we now refer to as “Boltzmann’s constant.”
That’s right, the factor of “k” that appears in the formula “S = k log W” — the formula engraved on Boltzmann’s memorial! — was actually introduced by Max Planck. Boltzmann expressed his results in terms of the ideal gas constant R.
Image: user Daderot on Wikipedia
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That’s right, the factor of “k” that appears in the formula “S = k log W” — the formula engraved on Boltzmann’s memorial! — was actually introduced by Max Planck. Boltzmann expressed his results in terms of the ideal gas constant R.
Image: user Daderot on Wikipedia
The transition from classical to quantum physics went about as smoothly as you would expect. Happy #QuantumDay!
(Unfortunately, I have no idea who made this classic physics meme. It has been around forever. If you know, please tell me!)
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undefined oblomov@sociale.network shared this topic
Gli ultimi otto messaggi ricevuti dalla Federazione
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@Yaku
Ho cominciato a cercare ma ci sono solo plugin per disabilitare l'editor a blocchi, non quello tradizionale. Continuo a cercare
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"By comparison, at least, the way the Chinese government speaks about AI is more modest. Yes, China’s economic leadership views AI as a priority and has boldly claimed it seeks to lead the world by 2030. Yet the rhetoric lacks the eschatological tone common in Silicon Valley. Chinese economic planners appear more interested in AI as a tool for industrial processes than as a means of creating a superintelligence that will reach the singularity. The State Council’s 2025 “AI+” initiative is focused entirely on efficiency-enhancing applications rather than intelligence explosions.
There is another important difference. China is banking far more heavily on simpler, lower-cost open-source AI models. In the US, most of the leading “frontier” AI models are secret and proprietary, in part as a business model and in part due to the apocryphal fears that the wrong actors could trigger human extinction. The smaller, lower-cost Chinese models may be seeking, in that sense, to be the more nimble 1970s Toyota rivals to the giant American cars produced by General Motors.
More importantly, China is hedging its bets by investing heavily in a wide range of other technologies that might reasonably be described as “the future”. In 2024, the country invested an estimated $940bn in clean-energy capex, broadly defined as renewables, electricity grids and energy storage (batteries), dwarfing its AI investments. In these sectors, AI is meant to be a complement — the glue rather than the structure.
While China’s overall economy remains weaker than it was in the 2010s, elements of this broader strategy seem to be bearing fruit."
https://www.ft.com/content/12581344-6e37-45a0-a9d5-e3d6a9f8d9ba
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@kepeken now you have two bad things
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@evadm
Perchè ci sono degli spostati mentali che casualmente si trovano al governo di nazioni, con desideri imperialisti.Quindi so che sarebbe meglio costruire scuole e ospedali con i soldi delle armi, ma se poi vengono bombardati son soldi spesi male... Un aeroplanino in questo mondo è investimento necessario.
Come dire che sarebbe bello se potessimo spendere invece che stipendi per poliziotti, in insegnanti.
Ma della polizia c'è bisogno.
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ho l'età per cui da femmina niente leva. Ma ho sempre ritenuto la leva come un posto infelice, inutile se non dannosa per alcuni. Io propongo come già fatto da altri in questo toot un periodo di servizio civile per tutti. Magari breve, tipo 6 mesi, lo troverei formativo e utile per lo sviluppo della persona e per la collettività. Non concordo con il "armati in nome della pace". I militari siano i professionisti che abbracciano questa carriera.
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A13
<< ... [la sovranità digitale dell'Europa]
senza la capacità di lettura critica di intenzioni di sviluppo "globali"
lascia i "territori" impotenti di fronte al rischio di assistere al ripetersi di
errori di strategia
inevitabili in passato
che "oggi"
richiedono la consapevolezza di cosa non fu possibile iniziare a raggiungere
"allora"
[ricerca e mantenimento di autonomia digitale]
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I miei ieri hanno fatto 51 anni di matrimonio. Secondo mia madre la base di questa riuscita e passare il tempo a far sentire in colpa mio padre. E mio padre ci casca da 50 anni e mezzo, Le do di bonus 6 mesi a mia madre ma sono ottimista. Visto il risultato chi sono io per contestare il metodo.
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@DigiDavidex per associazione di idee, beccati questa:
(c'è nebbia anche in pianura)
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47 years ago todayRoad to Ruin is the fourth studio album by American punk rock band the Ramones, released on this day in 1978, and the first Ramones album to feature new drummer Marky Ramone.
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