Today we thought about energy eigenstates and the “time independent Schrödinger equation.” Which personally I would rather think of as “the energy eigenstate equation,” but okay. #QM1
September 9, 2025 at 12:51 AM
Today we thought about energy eigenstates and the “time independent Schrödinger equation.” Which personally I would rather think of as “the energy eigenstate equation,” but okay. #QM1
Day 2 of #QM1 in the books. Of course I am going much slower than anticipated, so it was today that we actually zoomed through some historical motivation: Blackbody radiation, photoelectric effect, Rutherford/Bohr atoms, de Broglie waves. Made a tentative step toward the Schrödinger equation.
August 27, 2025 at 2:03 PM
Day 2 of #QM1 in the books. Of course I am going much slower than anticipated, so it was today that we actually zoomed through some historical motivation: Blackbody radiation, photoelectric effect, Rutherford/Bohr atoms, de Broglie waves. Made a tentative step toward the Schrödinger equation.
Today in QM1: just a basic motivational overview. I will give a quick summary of what quantum mechanics actually is, then some (logically reconstructed) history: blackbody radiation, photons, Bohr atom, de Broglie waves.
We're using David Tong's brand new book: www.amazon.com/Quantum-Mech...
We're using David Tong's brand new book: www.amazon.com/Quantum-Mech...
Quantum Mechanics: Volume 3: Lectures on Theoretical Physics
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August 25, 2025 at 12:19 PM
Today in QM1: just a basic motivational overview. I will give a quick summary of what quantum mechanics actually is, then some (logically reconstructed) history: blackbody radiation, photons, Bohr atom, de Broglie waves.
We're using David Tong's brand new book: www.amazon.com/Quantum-Mech...
We're using David Tong's brand new book: www.amazon.com/Quantum-Mech...
Mostly done with the motivational pep talk, today in #QM1 we dug into how wave functions work. In particular, thinking of them as superpositions of possible measurement outcomes. Introduced the Dirac delta, and explained that it represents an "eigenstate of position."
September 3, 2025 at 2:05 PM
Mostly done with the motivational pep talk, today in #QM1 we dug into how wave functions work. In particular, thinking of them as superpositions of possible measurement outcomes. Introduced the Dirac delta, and explained that it represents an "eigenstate of position."
New SARS-CoV-2 QM1 Sublineage Raises Concerns with Unique Mutation Profile
www.thailandmedical.news/news/new-sar...
www.thailandmedical.news/news/new-sar...
New SARS-CoV-2 QM1 Sublineage Raises Concerns with Unique Mutation Profile - Thailand Medical News
www.thailandmedical.news
September 19, 2025 at 3:51 AM
New SARS-CoV-2 QM1 Sublineage Raises Concerns with Unique Mutation Profile
www.thailandmedical.news/news/new-sar...
www.thailandmedical.news/news/new-sar...
En el blog > El modelo QM1 de PLD Space: nace el primer Miura 5
danielmarin.naukas.com/2025/11/25/e...
danielmarin.naukas.com/2025/11/25/e...
El modelo QM1 de PLD Space: nace el primer Miura 5 - Eureka
Cuando hace cosa de una década la empresa española PLD Space presentaba sus proyectos de cohetes suborbitales y orbitales, fueron pocos los que les prestaron demasiada atención. Por entonces, la […]
danielmarin.naukas.com
November 24, 2025 at 11:56 PM
En el blog > El modelo QM1 de PLD Space: nace el primer Miura 5
danielmarin.naukas.com/2025/11/25/e...
danielmarin.naukas.com/2025/11/25/e...
Today in #QM1 we escaped position space and took a journey to momentum space! Plane waves as momentum eigenstates, Fourier transforms, momentum operator, momentum version of the Born rule. This allows us to revisit the Schrödinger equation and see it as a "quantization" of a classical Hamiltonian.
September 5, 2025 at 4:36 PM
Today in #QM1 we escaped position space and took a journey to momentum space! Plane waves as momentum eigenstates, Fourier transforms, momentum operator, momentum version of the Born rule. This allows us to revisit the Schrödinger equation and see it as a "quantization" of a classical Hamiltonian.
What's better than an hour of Dave talking about dinosaurs? How about three and a half hours? Should keep a few of you busy at least. www.youtube.com/watch?v=-Qm1...
And have I ever looked this dramatic before?
And have I ever looked this dramatic before?
Dave Hone: T-Rex, Dinosaurs, Extinction, Evolution, and Jurassic Park | Lex Fridman Podcast #480
YouTube video by Lex Fridman
www.youtube.com
September 5, 2025 at 6:40 AM
What's better than an hour of Dave talking about dinosaurs? How about three and a half hours? Should keep a few of you busy at least. www.youtube.com/watch?v=-Qm1...
And have I ever looked this dramatic before?
And have I ever looked this dramatic before?
Then we started but didn't finish the wave packet for a free particle. Start with a Gaussian in position space, take the Fourier transform to get another Gaussian in momentum space. But the width of the first goes inversely to the width of the second -- uncertainty principle in action! #qm1
September 10, 2025 at 2:48 PM
Then we started but didn't finish the wave packet for a free particle. Start with a Gaussian in position space, take the Fourier transform to get another Gaussian in momentum space. But the width of the first goes inversely to the width of the second -- uncertainty principle in action! #qm1
L’interdiction des réseaux sociaux aux moins de 15 ans est examinée aujourd’hui au Sénat.
La proposition de loi met en avant des enjeux sanitaires et éducatifs. Mais une parole reste peu entendue : celle des collégiens eux-mêmes. Écoutons-les.
➡️ https://l.franceculture.fr/QM1
La proposition de loi met en avant des enjeux sanitaires et éducatifs. Mais une parole reste peu entendue : celle des collégiens eux-mêmes. Écoutons-les.
➡️ https://l.franceculture.fr/QM1
March 31, 2026 at 7:30 AM
L’interdiction des réseaux sociaux aux moins de 15 ans est examinée aujourd’hui au Sénat.
La proposition de loi met en avant des enjeux sanitaires et éducatifs. Mais une parole reste peu entendue : celle des collégiens eux-mêmes. Écoutons-les.
➡️ https://l.franceculture.fr/QM1
La proposition de loi met en avant des enjeux sanitaires et éducatifs. Mais une parole reste peu entendue : celle des collégiens eux-mêmes. Écoutons-les.
➡️ https://l.franceculture.fr/QM1
Today in #QM1 we completed our analysis of the Hamiltonian for two coupled spins. We noticed that the eigenvectors/values seemed to group into a "triplet" and a "singlet." Those are just evocative words right now, until we eventually study how to combine angular momenta.
October 8, 2025 at 2:03 PM
Today in #QM1 we completed our analysis of the Hamiltonian for two coupled spins. We noticed that the eigenvectors/values seemed to group into a "triplet" and a "singlet." Those are just evocative words right now, until we eventually study how to combine angular momenta.
And today in #QM1 we finished off that pesky harmonic oscillator, showing that the eigenvalues of a coherent state encode the time evolution of position and momentum of an ordinary classical oscillator. I thought it was pretty cool.
November 5, 2025 at 3:13 PM
And today in #QM1 we finished off that pesky harmonic oscillator, showing that the eigenvalues of a coherent state encode the time evolution of position and momentum of an ordinary classical oscillator. I thought it was pretty cool.
Started today's #QM1 class by quickly showing that evolution of the wave function preserves the total probability. That's possible to do from the non-relativistic Schrödinger eq, but involves deriving a continuity equation etc. It's pretty trivial when you use the unitary time-evolution operator.
September 26, 2025 at 3:28 PM
Started today's #QM1 class by quickly showing that evolution of the wave function preserves the total probability. That's possible to do from the non-relativistic Schrödinger eq, but involves deriving a continuity equation etc. It's pretty trivial when you use the unitary time-evolution operator.
Today in #QM1 we revisited the Born Rule (probability equals amplitude squared) in a more general context. Given a Hermitian observable, you can make projection operators from its eigenstates and associate a probability to any particular eigenvalue you might measure.
September 24, 2025 at 2:14 PM
Today in #QM1 we revisited the Born Rule (probability equals amplitude squared) in a more general context. Given a Hermitian observable, you can make projection operators from its eigenstates and associate a probability to any particular eigenvalue you might measure.
Today in #QM1: coherent states of the simple harmonic oscillator! These are the "most classical" that SHO states can be. For one thing, they saturate the Heisenberg Uncertainty Principle bound on (Δx)(Δp). Which means they look like Gaussian wave packets in position space.
November 3, 2025 at 5:20 PM
Today in #QM1: coherent states of the simple harmonic oscillator! These are the "most classical" that SHO states can be. For one thing, they saturate the Heisenberg Uncertainty Principle bound on (Δx)(Δp). Which means they look like Gaussian wave packets in position space.
What an unusual crossover. Lex Friedman and dinosaur paleontologist Dave Home 😃
www.youtube.com/watch?v=-Qm1...
🧪 ⚒️ #Paleobio #Geology
www.youtube.com/watch?v=-Qm1...
🧪 ⚒️ #Paleobio #Geology
Dave Hone: T-Rex, Dinosaurs, Extinction, Evolution, and Jurassic Park | Lex Fridman Podcast #480
YouTube video by Lex Fridman
www.youtube.com
September 5, 2025 at 7:15 PM
What an unusual crossover. Lex Friedman and dinosaur paleontologist Dave Home 😃
www.youtube.com/watch?v=-Qm1...
🧪 ⚒️ #Paleobio #Geology
www.youtube.com/watch?v=-Qm1...
🧪 ⚒️ #Paleobio #Geology
Today in #QM1 we started on Hilbert space, Dirac notation, and the formalism of quantum mechanics more generally. We revealed that our previous formulas for the wave function in position or momentum space could be thought of different ways of summing components times appropriate basis vectors.
September 15, 2025 at 6:50 PM
Today in #QM1 we started on Hilbert space, Dirac notation, and the formalism of quantum mechanics more generally. We revealed that our previous formulas for the wave function in position or momentum space could be thought of different ways of summing components times appropriate basis vectors.
I try to make sure that most #QM1 lectures have some physical content, not just math and notation, but I didn't quite succeed today. All about dual vectors and adjoints and matrix elements.
I did explain that the components of the bra <φ| are written as φ_n^*, and not φ_n, which often confuses me.
I did explain that the components of the bra <φ| are written as φ_n^*, and not φ_n, which often confuses me.
September 17, 2025 at 2:11 PM
I try to make sure that most #QM1 lectures have some physical content, not just math and notation, but I didn't quite succeed today. All about dual vectors and adjoints and matrix elements.
I did explain that the components of the bra <φ| are written as φ_n^*, and not φ_n, which often confuses me.
I did explain that the components of the bra <φ| are written as φ_n^*, and not φ_n, which often confuses me.
Great mistakes. February 1995. Division 189. QM1 Davis.
November 14, 2024 at 4:34 AM
Great mistakes. February 1995. Division 189. QM1 Davis.
カレンダーへの招待: ♡たま子の秘密のカレンダー♡
カレンダーに参加してみんなで予定を書き込めば、グループのスケジュールをいつでもどこでも簡単に把握できます。
timetr.ee
June 2, 2025 at 12:01 PM
Today in #QM1 we went back to being like a real physics class: solving differential equations. In particular, the Schrödinger equation for the simple harmonic oscillator. Some tricks get it into a form where some heroic 19th-century mathematician surely solved it, but we're doing it ourselves.
October 24, 2025 at 3:11 PM
Today in #QM1 we went back to being like a real physics class: solving differential equations. In particular, the Schrödinger equation for the simple harmonic oscillator. Some tricks get it into a form where some heroic 19th-century mathematician surely solved it, but we're doing it ourselves.
And today in #QM1 we did scattering and tunneling with a square barrier. Defined probability flux, calculated reflection and transmission coefficients. Noted a resonance where certain waves will pass right through certain barriers. Acknowledged that this is probably really interesting to engineers.
November 14, 2025 at 5:47 PM
And today in #QM1 we did scattering and tunneling with a square barrier. Defined probability flux, calculated reflection and transmission coefficients. Noted a resonance where certain waves will pass right through certain barriers. Acknowledged that this is probably really interesting to engineers.
Today in #QM1 we thought about the simple harmonic oscillator in terms of raising/lowering operators. Wrote them down, related them to x and p, figured out the Hamiltonian in terms of them, derived commutation relations.
October 29, 2025 at 2:42 PM
Today in #QM1 we thought about the simple harmonic oscillator in terms of raising/lowering operators. Wrote them down, related them to x and p, figured out the Hamiltonian in terms of them, derived commutation relations.
Back to real work today in #QM1: the Heisenberg Uncertainty Principle. We proved it, not much to report. Other than the proof in Tong's book, which I think it pretty standard, does prove the result but is singularly unilluminating. Not a proof from The Book, as Erdös would have said.
October 22, 2025 at 2:23 PM
Back to real work today in #QM1: the Heisenberg Uncertainty Principle. We proved it, not much to report. Other than the proof in Tong's book, which I think it pretty standard, does prove the result but is singularly unilluminating. Not a proof from The Book, as Erdös would have said.