I sure hope they start rolling the recording devices well before any collisions at the particle accelerators - so they can catch any high energy particles zooming off before the collision.
> “When you see a transmitted photon, you can’t know which of these occurred,” Steinberg says, adding that because photons are quantum particles in the quantum realm, the two outcomes can be in superposition—both things can happen at the same time. “The measuring device ends up in a superposition of measuring zero and measuring some small positive value.” But correspondingly, Steinberg notes, that also means that sometimes “the measuring device ends up in a state that looks not like ‘zero’ plus ‘something positive’ but like ‘zero’ minus ‘something positive,’ resulting in what looks like the wrong sign, a negative value, for this excitation time.”
While I am fascinated the ideas like those ( negative time, negative mass, and so on ), is it not possible that we are simply not able to measure those appropriately?
The trick is that we don't really have deeper understanding of "mass" and "time" so all we can talk about is the (classical) measurements we make. Paraphrasing Feynman:
Physicist's definition of time: "it is what is measured by a clock"
Philosopher's definition of time: "it is the thing that passes by when you wait!"
(Or even all the way back to Saint Augustine: when you're living day-to-day, time is as natural and obvious as could be; when you're trying to explain time in words, it's a morass of tautologies and contradictions.)
For non-relativistic classical mechanics these concepts plainly coincide. General relativity leads to unintuitive consequences but doesn't come into friction with "what passes when you wait" since humans are subject to GR. But humans are not meaningfully quantum-mechanical, and the philosopher's definition of time is meaningless for a photon. For QM, all we have is the physicists's definition; the negative time measurement observed in the lab is the only time it makes sense to talk about.
When you say "not able to measure time appropriately" I think you mean more precisely something like "not able to phrase a subatomic theory of time which aligns with our classical intuition" - e.g. a quantum theory of causality itself where classical time "falls out," kind of like how some physicists are looking for information-theoretic approaches to gravitation where mass "falls out." But it's a much bigger problem than measurement of time - if we come up with such a theory the measurements of "second" would be the same up to a minor correction, but supplemented by additional measurements of physical properties we don't understand yet.
> Physicist's definition of time: "it is what is measured by a clock"
I hate this quote, because it makes people think there is something unique about time. There is, but not because of this. We could similarly say "a meter is what a ruler measures" (defined by how far light moves in 1/299792458th of a second; a second is defined as 9192631770 Hz, or the transition of 2 hyperfine levels of a CS-133 atoms).
We can do this with any SI unit! What is an Ampere? You gotta define charge and frequency (time). What is a kilogram? You gotta define Planck's constant, the speed of light, and... frequency. Kelvin? Planck's constant, frequency, and kilo. Candela? Also depends on frequency. Mol? Well... actually this one is unique.
Truth is that these are not as "well defined" as one might think. They're kinda made up and arbitrary, and that's perfectly okay. In particle physics you often set hbar = 2pi = c = 1 (or if you're Mills, you include i). If we meet aliens, they would very likely have a different set of units, but their physics would look identical (they'd be isomorphic, i.e. we could translate between them).
So what is time? Distance? Mass? Energy? These are still very open questions at a base fundamental level. We treat them like axioms but even math still questions axioms and would love to remove them (and just like math, axioms are typically developed in hindsight). Someone might give you some definition for these things and you might be satisfied, but that doesn't mean there is a question one level deeper that's unknown. Beware this trick, as you'll fool yourself into thinking you know more than you do (it's quite common, and we all do it. I'm not trying to stand on a pedestal, every human does this and in abundance. Sweep things under the rug, but don't forget that you've done this).
(also, this quote is usually attributed to Einstein, not Feynman)
A lot of physics experiments are very indirect, and you're not actually measuring the 'thing' you're looking for. As an example, in particle collision experiments, you're often looking at how the resulting collisions behave, and then applying our current understanding and models to reason about why the resulting collisions behave the way they do. Basically, it's like saying, 'This particle X had Y behavior, which is explained by our current model that says there must be a Z interacting with X to produce Y.' This is, of course, an extreme simplification, but it illustrates why we can claim with a high level of confidence that certain 'unmeasurable' things must exist.
> A lot of physics experiments are very indirect, and you're not actually measuring the 'thing' you're looking for.
This is actually true for any experiment. Just at a macro scale the proxy is often less complicated. A simple example of this might be measuring how big a piece of paper is. You get a ruler and measure it, right? Your measurement is an approximation of the ruler's measurement, which is an approximation based on the standard meter. I have a bunch of rulers and I can tell you that none of them measure exactly the same. Usually it doesn't matter though because the difference is much smaller than the level of uncertainty and we're usually measuring with enough accuracy that we don't care.
What physicists do is a generalization of this same thing. Usually much more accurately than your paper experiment. But yes, in high energy physics (HEP) you're usually measuring very indirectly and based on theory. This is a big part of the Von Neumann's Elephant thing. Fitting data is easy, explaining it isn't. The casual nature is the critical aspect
An important way to think about this is what actually happens when you do an experiment: i.e. the measurement is ultimately happening at your eye-ball, and is a chain of linked effects we believe we understand all the way down to the item under test (which is part of the reason metrology itself is fascinating).
I keep being reminded about how our understanding of the world changes ( with some rather dramatic examples in our own history ). Still, in cases like these I like to quote Pratchett:D
“A thousand years ago we thought the world was a bowl,” he said. “Five hundred years ago we knew it was a globe. Today we know it is flat and round and carried through space on the back of a turtle.” He turned and gave the High Priest another smile. “Don’t you wonder what shape it will turn out to be tomorrow?”
I am not suggesting parent is right, but who knows what the future holds.
New scientific models tend to look very much like the older models in some relevant limit, even when they are fundamentally very different. Einstein's relativity looks a whole lot like Newton's relativity at low speeds. Large collections of quantum-mechanical particles tend to behave classically. This is not an accident of history—the old models worked in some domain, which is why they became accepted models. I will counter your Pratchett quote with one from Asimov:
"When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."
This has been the winning strategy so far, as using the map (theoretical model) leads to excellent agreement with experiment, while the territory (ground level reality) steadfastly defies common sense interpretation.
Well let me know when someone reproduces someone else's time traveling experiment. Until then I'm going to bet that the plethora of (untested, often philosophical) exotic QM interpretations are based on an incomplete model and are as misguided as they seem.
The problem with QM isn't that it isn't predictive, but that people in the field often seem incredibly sure of fundamental nuances of reality that have never been experimentally tested.
I sure hope they start rolling the recording devices well before any collisions at the particle accelerators - so they can catch any high energy particles zooming off before the collision.
Sensational discovery requires extraordinary evidence. I’ll wait until other scientists in the field can review it. Or even better replicate it.
Or something happen in additional dimension(s).
https://archive.is/WaiOv
> “When you see a transmitted photon, you can’t know which of these occurred,” Steinberg says, adding that because photons are quantum particles in the quantum realm, the two outcomes can be in superposition—both things can happen at the same time. “The measuring device ends up in a superposition of measuring zero and measuring some small positive value.” But correspondingly, Steinberg notes, that also means that sometimes “the measuring device ends up in a state that looks not like ‘zero’ plus ‘something positive’ but like ‘zero’ minus ‘something positive,’ resulting in what looks like the wrong sign, a negative value, for this excitation time.”
While I am fascinated the ideas like those ( negative time, negative mass, and so on ), is it not possible that we are simply not able to measure those appropriately?
The trick is that we don't really have deeper understanding of "mass" and "time" so all we can talk about is the (classical) measurements we make. Paraphrasing Feynman:
Physicist's definition of time: "it is what is measured by a clock"
Philosopher's definition of time: "it is the thing that passes by when you wait!"
(Or even all the way back to Saint Augustine: when you're living day-to-day, time is as natural and obvious as could be; when you're trying to explain time in words, it's a morass of tautologies and contradictions.)
For non-relativistic classical mechanics these concepts plainly coincide. General relativity leads to unintuitive consequences but doesn't come into friction with "what passes when you wait" since humans are subject to GR. But humans are not meaningfully quantum-mechanical, and the philosopher's definition of time is meaningless for a photon. For QM, all we have is the physicists's definition; the negative time measurement observed in the lab is the only time it makes sense to talk about.
When you say "not able to measure time appropriately" I think you mean more precisely something like "not able to phrase a subatomic theory of time which aligns with our classical intuition" - e.g. a quantum theory of causality itself where classical time "falls out," kind of like how some physicists are looking for information-theoretic approaches to gravitation where mass "falls out." But it's a much bigger problem than measurement of time - if we come up with such a theory the measurements of "second" would be the same up to a minor correction, but supplemented by additional measurements of physical properties we don't understand yet.
We can do this with any SI unit! What is an Ampere? You gotta define charge and frequency (time). What is a kilogram? You gotta define Planck's constant, the speed of light, and... frequency. Kelvin? Planck's constant, frequency, and kilo. Candela? Also depends on frequency. Mol? Well... actually this one is unique.
Truth is that these are not as "well defined" as one might think. They're kinda made up and arbitrary, and that's perfectly okay. In particle physics you often set hbar = 2pi = c = 1 (or if you're Mills, you include i). If we meet aliens, they would very likely have a different set of units, but their physics would look identical (they'd be isomorphic, i.e. we could translate between them).
So what is time? Distance? Mass? Energy? These are still very open questions at a base fundamental level. We treat them like axioms but even math still questions axioms and would love to remove them (and just like math, axioms are typically developed in hindsight). Someone might give you some definition for these things and you might be satisfied, but that doesn't mean there is a question one level deeper that's unknown. Beware this trick, as you'll fool yourself into thinking you know more than you do (it's quite common, and we all do it. I'm not trying to stand on a pedestal, every human does this and in abundance. Sweep things under the rug, but don't forget that you've done this).
(also, this quote is usually attributed to Einstein, not Feynman)
For info on SI units: https://www.bipm.org/en/si-base-units/mole
A lot of physics experiments are very indirect, and you're not actually measuring the 'thing' you're looking for. As an example, in particle collision experiments, you're often looking at how the resulting collisions behave, and then applying our current understanding and models to reason about why the resulting collisions behave the way they do. Basically, it's like saying, 'This particle X had Y behavior, which is explained by our current model that says there must be a Z interacting with X to produce Y.' This is, of course, an extreme simplification, but it illustrates why we can claim with a high level of confidence that certain 'unmeasurable' things must exist.
What physicists do is a generalization of this same thing. Usually much more accurately than your paper experiment. But yes, in high energy physics (HEP) you're usually measuring very indirectly and based on theory. This is a big part of the Von Neumann's Elephant thing. Fitting data is easy, explaining it isn't. The casual nature is the critical aspect
An important way to think about this is what actually happens when you do an experiment: i.e. the measurement is ultimately happening at your eye-ball, and is a chain of linked effects we believe we understand all the way down to the item under test (which is part of the reason metrology itself is fascinating).
the nice thing about particle physics though is that usually the existing theory predicts the numbers to ~18 decimal places.
Quantum mechanics seems intent on declaring that their particular map is the territory.
Isn't it more like "Nobody has found a better way of describing the territory than quantum mechanics"
"And if they think they did they're batshit crazy obviously"
Merely the best yet representation of the world around us. The nerve!
I keep being reminded about how our understanding of the world changes ( with some rather dramatic examples in our own history ). Still, in cases like these I like to quote Pratchett:D
“A thousand years ago we thought the world was a bowl,” he said. “Five hundred years ago we knew it was a globe. Today we know it is flat and round and carried through space on the back of a turtle.” He turned and gave the High Priest another smile. “Don’t you wonder what shape it will turn out to be tomorrow?”
I am not suggesting parent is right, but who knows what the future holds.
New scientific models tend to look very much like the older models in some relevant limit, even when they are fundamentally very different. Einstein's relativity looks a whole lot like Newton's relativity at low speeds. Large collections of quantum-mechanical particles tend to behave classically. This is not an accident of history—the old models worked in some domain, which is why they became accepted models. I will counter your Pratchett quote with one from Asimov:
"When people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."
This response actually convinces me as more accurate. Thank you.
I think there will be some light Asimov (re)reading in my future; as a kid you focus on different things.
This has been the winning strategy so far, as using the map (theoretical model) leads to excellent agreement with experiment, while the territory (ground level reality) steadfastly defies common sense interpretation.
Well let me know when someone reproduces someone else's time traveling experiment. Until then I'm going to bet that the plethora of (untested, often philosophical) exotic QM interpretations are based on an incomplete model and are as misguided as they seem.
The problem with QM isn't that it isn't predictive, but that people in the field often seem incredibly sure of fundamental nuances of reality that have never been experimentally tested.
More likely "Evidence of Miscalibrated Instruments Found in Quantum Physics Lab"