In the last four posts (Quantum Measurement, Wavefunction Collapse, Quantum Decoherence, and Measurement Specifics), I’ve explored the conundrum of measurement in quantum mechanics. As always, you should read those before you read this.
Those posts covered a lot of ground, so here I want to summarize and wrap things up. The bottom line is that we use objects with classical properties to observe objects with quantum properties. Our (classical) detectors are like mousetraps with hair-triggers, using stored energy to amplify a quantum interaction to classical levels.
Also, I never got around to objective collapse. Or spin experiments.
In the last three posts (Quantum Measurement, Wavefunction Collapse, and Quantum Decoherence), I’ve explored one of the key conundrums of quantum mechanics, the problem of measurement. If you haven’t read those posts, I recommend doing so now.
I’ve found that, when trying to understand something, it’s very useful to think about concrete real-world examples. Much of my puzzling over measurement involves trying to figure out specific situations and here I’d like to explore some of those.
Starting with Mr. Schrödinger’s infamous cat.
In the last two posts (Quantum Measurement and Wavefunction Collapse), I’ve been exploring the notorious problem of measurement in quantum mechanics. This post picks up where I left off, so if you missed those first two, you should go read them now.
Here I’m going to venture into what we mean by quantum coherence and the Yin to its Yang, quantum decoherence. I’ll start by trying to explain what they are and then what the latter has to do with the measurement problem.
The punchline: Not very much. (But not exactly nothing, either.)
The previous post began an exploration of a key conundrum in quantum physics, the question of measurement and the deeper mystery of the divide between quantum and classical mechanics. This post continues the journey, so if you missed that post, you should go read it now.
Last time, I introduced the notion that “measurement” of a quantum system causes “wavefunction collapse”. In this post I’ll dig more deeply into what that is and why it’s perceived as so disturbing to the theory.
Caveat lector: This post contains a tiny bit of simple geometry.
Over the last handful of years, fueled by many dozens of books, lectures, videos, and papers, I’ve been pondering one of the biggest conundrums in quantum physics: What is measurement? It’s the keystone of an even deeper quantum mystery: Why is quantum mechanics so strangely different from classical mechanics?
I’ll say up front that I don’t have an answer. No one does. The greatest minds in science have chewed on the problem for almost 100 years, and all they’ve come up with are guesses — some of them pretty wild.
This post begins an exploration of the conundrum of measurement and the deeper mystery of quantum versus classical mechanics.
Last year I kicked off the new year with a post about open and challenging questions in physics. Those remain open and challenging and probably will for some time. Some of them are very old (and very unresolved) questions; others were from modern scientific efforts and understandings. It’s possible we may never find answers for some.
At some point, for some reason, about a month ago I started making a list of things I thought were probably true; things I believe in. I say “probably” because, as with those open science questions, we don’t know the truth of these things; many are vigorously debated.
Some of what follows pertains to those science questions, some of it is more social observation on my part.
Not too long ago I wrote about an apparent issue between posts written in the Classic Editor and how the WordPress Reader sometimes displays them with no paragraph breaks. The post looks fine on the blog’s website, but the WP Reader isn’t recognizing its paragraphs. (This problem still hasn’t been fixed, and I continue to notice posts where it obviously happened.)
That post went longer than I expected because I had to explain the HTML aspects of why the problem seems to happen and how to go about trying to correct it. I meant to get into other foibles of the Reader but ran out of room.
This post adds an extra room just for the WP Reader.
It’s actually an old debate — in fact, it’s a variation on the Ship of Theseus — but modern day science fiction gives it a new spin. At root it’s a question about exactly where our identity as self-aware conscious beings actually resides. I don’t find it paradoxical so much as intriguing.
Recently Sabine Hossenfelder jumped into the discussion with a video asking whether Captain Kirk dies every time he uses the transporter. Not just him, of course, but everyone who uses it.
As with trees falling in forests, the answer depends on defining key terms. This case depends on exactly what we mean by “dies” and “Kirk” — the latter being the Ship of Theseus.
It’s a New Year, so it’s time for that Janus backward and forward State of the Blog Post. (I did plenty looking back in the previous post, so today I’m looking mostly in the other direction.)
As I’ve mentioned, I framed 2020 as a year for changes. Many of them got sidelined (or outright derailed) but the year did result in some decisions that matter here. I find I’ve gone beyond my rope when it comes to what I’m going to begin always referring to as “fantasy bullshit” (FBS).
That’s not to say fantasy bullshit is all bad (some is fun; some might even be necessary), but I am going to start calling it what it is.
At the beginning of the week, I mentioned I’m reading Our Mathematical Universe (2014), by Max Tegmark. His stance on inflation, and especially on eternal inflation, got me really thinking about it. Then all that thinking turned into a post.
It happened again last night. That strong sense of, “Yeah, but…” With this book, that’s happening a lot. I find something slightly, but fundamentally, off about Tegmark’s arguments. There seems an over-willingness to accept wild conclusions. This may all say much more about me than about Tegmark, which in this case is perfect irony.
Because what set me off this time was his chapter about human intuition.