⚛️🧪Is Superposition Really an "OR"? If a quantum system is in a superposition state "A+B", does it mean that "A AND B" are true, or that "A OR B " is true, or something else? An example of why ordinary language is not easily applied to #quantum physics. profmattstrassler.com/2025/04/14/i...

⚛️🧪In the #quantum double slit experiment, the famous #interference pattern disappears if we measure which slit the particle went through. Why does it disappear? It's often described in vague, mystical terms, but in fact it's conceptually straightforward: profmattstrassler.com/2025/04/03/d...

⚛️The interference of water waves happens somewhere -- wherever the waves are, obviously. But #quantum interference happens... nowhere. If you try to say exactly where two #entangled particles interfere, you will find yourself lost in space. profmattstrassler.com/2025/03/31/q...

⚛️🧪If particles are #entangled, observing #quantum interference effects can be subtle, often requiring measuring multiple particles. As a result, quantum interference cannot generally be located in a specific place, unlike interference of e.g. water waves. profmattstrassler.com/2025/03/31/q...

⚛️🧪In the #quantum double-slit experiment, it's natural to ask, "where does the interference occur?" But it's a dicey question: an answer is only possible in special situations, as when the particles are independent (i.e. their behavior is "uncorrelated".) profmattstrassler.com/2025/03/28/q...

⚛️🧪The #quantum double-slit experiment shows an interference pattern; but what is interfering with what? Today I explore examples that show how seemingly minor changes can eliminate interference, and why locating the interference in space is ... problematic. profmattstrassler.com/2025/03/26/q...

"Nobody really knows what the elementary laws of nature are like yet; there are still too many unknowns." Still, @mattstrassler.bsky.social's astounding book Waves in an Impossible Sea is for me a refuge from the constant barrage of chaos and danger surrounding us right now.

⚛️🧪Here are 10 examples of simple one- or two-particle systems in #quantum superpositions. Some show quantum interference (like double-slit), others don't. Do you see the pattern that distinguishes the two groups? Why & when does interference happen (...or not)? profmattstrassler.com/2025/03/20/q...

⚛️🧪In yesterday's post, I showed a simple example where one particle can give the same #quantum interference as in the double-slit experiment. Then I posed a puzzle about two particles, which has generated a debate in the comments. Can you solve the riddle? profmattstrassler.com/blog/

⚛️🧪A super-simple example of #quantum #interference, in which an interference pattern emerges #particle by particle (as in the double slit expt). It frames a question clearly: is the particle interfering with itself, or is it not? Answer to follow. profmattstrassler.com/2025/03/18/q...

⚛️🧪I've been interviewed on the Blackbird #Physics YouTube channel by UMich. grad student & LHC physicist Ibrahim Chahrour. The interview, aimed largely at physics undergrad & grad students, covers mass, fields, #particles & the #Higgs boson. www.youtube.com/watch?v=ly15...

I was curious about this so I corrected the scale.

🔭 The eclipsed Moon from Earth, and the eclipsing Earth from the Moon spaceweathergallery2.com/indiv_upload...

⚛️🧪To make sense of the #quantum double slit experiment, one must first learn this strange lesson: in 1920s quantum physics, the interference arises *neither* from particles moving through both slits *nor* from a wave function moving through both slits. profmattstrassler.com/2025/03/13/d...

This is another one that is a "must read" to entertain myself this gloomy/cloudy afternoon... ❤️

⚛️🧪Do wave functions describing #quantum objects actually "collapse" (i.e., suddenly change shape and lose pieces) when those objects are measured? Here's how to think about the issue clearly, without getting mired in illogical conundrums and bad arguments profmattstrassler.com/2025/03/10/d...

⚛️🧪A #quantum superposition, in which a wave function contains 2 possibilities simultaneously, does not mean that both possibilities occur. It means that one *or* the other may occur; e.g. a quantum particle cannot be observed to go in 2 directions at once. profmattstrassler.com/2025/03/06/c...

#quantum #physics: In measurements of ultra-microscopic objects, the resulting measurement evidence is fragile & easily lost. How do experimental physicists preserve the evidence quickly, before it's too late? profmattstrassler.com/2025/03/03/m...

⚛️🧪What is a measurement? A tricky question, especially in our #quantum world. As a first step, here's a way to think about it: a sketch of a simple measurement device in a simple quantum setting, one that we can use in future in more complex situations. profmattstrassler.com/2025/02/27/w...

⚛️🧪A grasp of the "space of possibilities" [a.k.a. "configuration space"], and how to convert from it to the physical space we live in, is crucial in #physics, especially #quantum physics. I've added an article to help readers develop more intuition for it. profmattstrassler.com/articles-and...

⚛️🧪#Wave functions in #quantum field theory are hard to visualize, & thus hard to understand. Today I address that problem, partially depicting the wave function for a field's vacuum state (no "particles") & comparing it to that of a state with 1 "particle". profmattstrassler.com/2025/02/25/t...

⚛️🧪A #particle in 1920s #quantum #physics is a different beast from a "particle" in modern quantum field theory. This important distinction is inherently confusing. My aim this week is to bring a new level of pedagogical clarity to this tricky issue. profmattstrassler.com/2025/02/24/t...

⚛️🧪From this example one can see (even more so in the 2-dimensional versions) that in 1920s quantum physics the double-slit interference pattern arises from interfering *possibilities*. [But caution: quantum field theory changes the perspective!] profmattstrassler.com/2025/02/20/c...

⚛️🧪Yesterday I posted an animation of a #quantum wave function & asked readers to try to interpret it. Most people thought it shows 2 particles passing/colliding. In fact it shows just one particle in the midst of a disguised double-slit experiment! profmattstrassler.com/2025/02/21/i...

⚛️Most people -- even #physics students -- mistakenly think this #quantum wave function shows two #particles approaching each other and interfering with one another. But no. What, in fact, is it?

⚛️🧪A brain teaser for blog readers: here's an interesting #quantum #wave function evolving over time, shown 3 ways. Can you interpret what this wave function describes? Note the interference effects... what do they represent? Answers tomorrow. profmattstrassler.com/2025/02/20/c...

⚛️🧪What is a wave function in #quantum #physics? It's not a thing; it sits outside the physical system it describes. Its origin dates to the 1830s, not the 1920s; the word "#wave" in its name often isn't appropriate; and one needn't even use it. profmattstrassler.com/2025/02/19/s...

⚛️🧪Actor & science communication expert Alan Alda has a #podcast "Clear & Vivid" which often covers topics in #science and science communication. I was delighted to be on the podcast; our conversation about waves of the cosmos & my recent book is now posted clear-vivid-with-alan-alda.simplecast.com

Tomorrow is PODCAST DAY! Alan Alda speaks with with @mattstrassler.bsky.social . What Are You Made Of? The answer, regrettably, is unbelievable... Available tomorrow 👉 bit.ly/3Q0rUMV After production costs, all proceeds of #ClearAndVivid go to @AldaCenter . 🗣️💙

⚛️🧪How should you visualize a Schroedinger wavefunction in #quantum #physics? Here are a few methods that are useful in simple cases. In more complicated situations, one or another of these methods may still work, so it's good to be familiar with them all. profmattstrassler.com/2025/02/17/h...

More BlueSky in Europe, which needs as much as it can get

⚛️🧪Spikes in images from the Large Hadron Collider are reminiscent of those seen in recording studios; indeed, the universe resembles a #musical instrument. But it's out of tune, and we don't know how it got its specific "notes". #ParticlePhysics #HiggsField profmattstrassler.com/2025/02/13/a...

⚛️🧪From Pioneer Works, my new article on their "Picture This" series. "Our universe is out of tune. For PW Broadcast, theoretical physicist Matt Strassler reveals how cosmic frequencies arise from the Higgs field." pioneerworks.org/broadcast/pi...

⚛️🧪Today I'll show you why #particles of infinitesimal size are incompatible with #quantum #physics of the 1920s: defining such objects requires the inclusion of #Einstein's #relativity, but doing so breaks apart the whole conceptual/mathematical structure. profmattstrassler.com/2025/02/11/e...

⚛️Do elementary #particles, in the sense of infinitesimally small objects, actually exist? Arguably no. And certainly not in "quantum mechanics", the #quantum #physics of the 1920s. (1st of 2 posts: on the quantum symmetry between position and motion) profmattstrassler.com/2025/02/10/e...

Just so you're keeping score: the judicial branch no longer has a role to play, according to the executive branch.

Bluesky, out across the great ocean to a special port

From Robert Reich: "According to the best source I’ve found on this (Nathan Tankus’s Crises Notes), Musk and his rats have now gained unrestricted access to your Social Security number, your confidential bank information, your confidential medical information, and much more."

🧪As expected, the Musk/Trump govt has attacked the US #university system. As of Monday, apparently, overhead on National Institute of Health grants is capped at 15%, with massive impact on every #research university. Other govt agencies will surely follow. profmattstrassler.com/2025/02/09/a...

⚛️🧪What's an electron? The answer changed dramatically from 1900 to 1925 to 1950. The 1920s view, that of Heisenberg and Schrodinger, is best known, but is out of date and rather misleading. The modern view comes from #quantum field theory of the 1950s. profmattstrassler.com/2025/02/06/w...

The sky may be blue. But these are bad, bad lands, with no obvious safe passage, and the heat is insufferable. The only good news is that these mountains are much smaller than they appear.

🔭⚛️🧪I had a great conversation about #physics, #humans & the #universe with @dylan_curious (YouTube channel with a focus on #AI) covering everything from electrons to aliens to the universe-as-a-simulation (complete with glitches[?!]) I'm sure you'll enjoy it! www.youtube.com/watch?v=L46t...

100 years of Quantum Mechanics: George Uhlenbeck and Samuel Goudsmit postulated in 1925 the idea of intrinsic angular moment of the electron, which we now call spin. Three years later it would be incorporated into Dirac’s relativistically covariant theory of fermions (the “Dirac equation”).

At the #LHC, ordinary jets (sprays of particles) are common, and not easy to distinguish from "jets-of-jets" caused by new particles subject to a new strong force. Recently, using a simple, elegant method, the ATLAS experiment searched for jets-of-jets. profmattstrassler.com/2025/01/29/a...

⚛️ #Quantum #Physics; so strange, subtle, & hard to make sense of. In 2025, a quantum centenary, I'll take on some of its difficult questions on my blog. To start: the (in)famous double-slit experiment, examined with the extreme care that it requires: profmattstrassler.com/2025/01/16/d...

The sky is still blue somewhere. In Japan, for instance. Autumn is a time for wistful melancholy, savoring the last days of warmth before a brutal winter..

Somewhere, far from here, the sky is still blue

The best thing about the inauguration being indoors is that the size of the attending crowd can't so easily be overestimated.

Despite the cold and gloom, there are always photos of Bluesky

Just finished @mattstrassler.bsky.social 's waves in an impossible sea. A masterpiece of decoding jargon and false analogies. Instead of the molasses analogy, the Higgs field is seen as a stiffening agent for wavicle fields. Right; he replaces a lot of the confusing jargon too.