I don't get the distinction between "a wave that has particle like properties and particles that have wave like properties." Defining something that has both wave and particle properties as either a wave or particle seems meaningless and ambiguous in the context of quantum mechanics.
This was my hang-up as well, but Tim's point about mass may be the key here. Would it be technically, formally correct to say that wave-particle duality ascribes wave-like properties to particles, but not necessarily vice-versa? I think we may be conflating it to mean "all things are both waves and particles", which is too broad. The particle-like behavior of waves (i.e. photons from light) is established by the observations of quantized energy, right?
Light is massless and "is" a wave. It can behave as a particle, called the photon, which is also massless.
An electron has mass and "is" a particle. It can behave as a wave, but it's really a probability function that describes the possible locations of the particle, because a wave can't have mass.
What you're saying is basically that the electron is giving the illusion of acting as a wave. I don't agree. When an electron acts like a wave it acts like a wave in the same way a wave acts like a wave. Distinguishing between the two behaviors is wrong.
I would say that the problem with the actual particle waving is that inertia is still a thing.
Also, the probability waves in two dimensions as it propagates forward. Essentially, for a free particle, the probability wave is a plane that corkscrews as it travels through space.
For me in my modern class, the idea that it is the probability that waves and not the actual particle took me over a month to "get."
This is just wrong. The entire point of wave-particle duality is that for quantum-mechanical entities neither a wave-like nor particle-like description is entirely correct. There are no "particles that are sometimes wave-like" or "waves that are sometimes particle-like"; both electrons and photons are quantum-mechanical entities that in some situations can be observed to have properties that would classically be associated with waves, and sometimes display can be observed to have properties that would classically be associated with particles. For both photons and electrons, the situations wherein they are wave-like and wherein they are particle-like are the same.
The probability-amplitude that determines where the "particle" is likely to be observed is wave-like for any "particle" and can self-interfere. Fundamentally, wave mechanics underlies the behaviour of the observable "particle".
There is no distinction. You are correct to see this as ambiguous, because the distinction is based on misconception.
I was merely pointing out that for light, its the electric and magnetic fields that are waving and for particles it is the probability that is waving. That is a distinction between them. A way to imagine it is that light is made up of what it is that is propagating whereas for a particle, it doesn't make sense to say that the electron is made up of probability.
In quantum field theory, which is the more fundamental form of quantum mechanics (for lack of a better word), particles are defined differently, so the idea of wave-particle duality is kinda of discarded.
VERY qualitatively, there're only fields, but because these fields are quantum, they cannot have any intensity. Instead it must always be a multiple of a certain quantity called the quantum of the field. A particle is simply a ripple (or "local excitation") of the field that has that minimum value of intensity and it kinda looks like a classical particle, but not quite. So the photon is a ripple in the photon field (also called electromagnetic field), the electron is a ripple in the electron field, the Higgs is a ripple in the Higgs fields, the graviton should be a ripple in the gravitational field (but damn you gravity!), and so on for all elementary particles. With this plus math you get the behaviour associated with wave-particle duality and more.
Now we are getting into something that I have yet to study, maybe this year, but quick research on wikipedia on photons...
Nevertheless, the photon is not a point-like particle whose trajectory is shaped probabilistically by the electromagnetic field, as conceived by Einstein and others; that hypothesis was also refuted by the photon-correlation experiments cited above. According to our present understanding, the electromagnetic field itself is produced by photons, which in turn result from a local gauge symmetry and the laws of quantum field theory (see the Second quantization and Gauge boson sections below).
The only problem is that it isn't cited but generally physics pages are kept quite up to date by bored grad students.
This was my hang-up as well, but Tim's point about mass may be the key here. Would it be technically, formally correct to say that wave-particle duality ascribes wave-like properties to particles, but not necessarily vice-versa? I think we may be conflating it to mean "all things are both waves and particles", which is too broad. The particle-like behavior of waves (i.e. photons from light) is established by the observations of quantized energy, right?
Light is massless and "is" a wave. It can behave as a particle, called the photon, which is also massless.
An electron has mass and "is" a particle. It can behave as a wave, but it's really a probability function that describes the possible locations of the particle, because a wave can't have mass.
Does that seem accurate?
Is nonsense, and I should have gone to bed rather than post it, yes?
In quantum field theory, which is the more fundamental form of quantum mechanics (for lack of a better word), particles are defined differently, so the idea of wave-particle duality is kinda of discarded.
VERY qualitatively, there're only fields, but because these fields are quantum, they cannot have any intensity. Instead it must always be a multiple of a certain quantity called the quantum of the field. A particle is simply a ripple (or "local excitation") of the field that has that minimum value of intensity and it kinda looks like a classical particle, but not quite. So the photon is a ripple in the photon field (also called electromagnetic field), the electron is a ripple in the electron field, the Higgs is a ripple in the Higgs fields, the graviton should be a ripple in the gravitational field (but damn you gravity!), and so on for all elementary particles. With this plus math you get the behaviour associated with wave-particle duality and more.
From an "intuition" standpoint (as much as intuition can mean anything here) that sounds about as reasonable as anything else in quantum mechanics.
The behavior is the empirically observed behavior.
The most useful math to predict what we observe is the math we use.
Why should any phenomena or "events" that occur on a scale far below what we normally experience follow any kind of analogy to anything we know well?
Why should a particle behave in any way "like a pingpong ball" or move in a "straight lines"? What does "straight line" mean anyway? It's at least as vision/human perception bound a concept as point particle, and may have no analog in reality. Heck what straight OR curved "line" occurs in the universe?
Does the concept of "continuous" (which is required for the concept of "line" ) even really mean anything other than a kind of estimation or way we parse information into a neat, single concept? Isn't everything composed of vast numbers of "discrete" things?
Images on an LCD TV screen are composed of discrete pixels that just have distinct values for their color. Concepts like lines & shapes don't really exist on that meta-universe of the TV. Must lines and the concepts of shape underly any meta-universe including ours?
It's strange. We acknowledge a billiard ball (or any solid thing) is not continuous, not round, but really composed of vast numbers of "particles" interacting with each others... Yet why do we insist on thinking of those "particles" as acting a little like our old concept of billiard balls? Especially when just 2 seconds ago, we already did away with the concept of a billiard ball as meaningless.
So the whole universe might be a bunch of fields and particles are just manifestations of those fields and act nothing like billiard balls? Cool.
I'm actually quite shocked at how many people posted. For now I'm just going to take a look at some of the links posted. I haven't seen any nearby and cheap community colleges that offer the class just yet.
I'm actually looking to get into the mathematics of quantum mechanics rather than word-based conceptual explanations of the quantum level--which is why I've been starting with Lagrangian mechanics.
So far I've been trying to read through this text on path integrals. At this point I can say I have a reasonable understanding up to page 7 after a month. LOL
My other deduction is that this field is populated by people far smarter than I. In anycase, the above text is far too dense for me because i don't have the background with Lagrangian mechanics. Right now I'm trying to figure out the Euler-Lagrange equation.
Does anyone have any thoughts/critiques on how to continue from here? Or if I'm even starting in the right place?
btw: a huge thanks to everyone for their suggestions. In particular to 1drop. That link looks like a great place to start hacking away.
So to be clear (since it seems that Galaxia, toto, and Tim are now all on the same page), this...
Is nonsense, and I should have gone to bed rather than post it, yes?
Yes
Light is a classical wave, but it really is composed of millions of excitations of the quantum photon field. If you decrease the intensity of a light beam so that there're only a couple of photons, you stop being able to describe light as a classical wave and start being able to describe it as a bunch of billiard balls. Ok, quantum billiard balls, but still.
Why can't millions of excitations of the electron field add up to form a "classical electron wave", like light? Because electrons are fermions and photons are bosons, which is a fancy way of saying "Pauli says they can't". Fermions hate being close to each other, while bosons love it.
And mass plays no role. Having mass doesn't make something less wavy and more particly.
@dcartist
Turns out that quantum particles, the excitations of quantum fields, really do behave a LOT like "pingpong balls" (not completely, obviously). I kid you not, they travel in straight lines, occupy a very small region of space, bounce off of surfaces, can collide with each other, etc...
Light is a classical wave, but it really is composed of millions of excitations of the quantum photon field. If you decrease the intensity of a light beam so that there're only a couple of photons, you stop being able to describe light as a classical wave and start being able to describe it as a bunch of billiard balls. Ok, quantum billiard balls, but still.
Why can't millions of excitations of the electron field add up to form a "classical electron wave", like light? Because electrons are fermions and photons are bosons, which is a fancy way of saying "Pauli says they can't". Fermions hate being close to each other, while bosons love it.
And mass plays no role. Having mass doesn't make something less wavy and more particly.
@dcartist
Turns out that quantum particles, the excitations of quantum fields, really do behave a LOT like "pingpong balls" (not completely, obviously). I kid you not, they travel in straight lines, occupy a very small region of space, bounce off of surfaces, can collide with each other, etc...
Thanks for the more thorough edited reply. Nice simplified description of fermions vs. bosons! Now I just need to sit tight and wait until someone wants to learn molecular toxicology or bioanalytical chemistry...
Thanks for the more thorough edited reply. Nice simplified description of fermions vs. bosons! Now I just need to sit tight and wait until someone wants to learn molecular toxicology or bioanalytical chemistry...
Haha! Despite studying physics, I think our society and the media have a somewhat unhealthy infatuation with the "sexyness" of physics, giving less attention to other much more complex sciences like chemistry and biology. I mean, I think that an educated layman is aware that the two major areas of physics are quantum mechanics and general relativity, yet I don't know exactly the major areas of chemistry or important fields of research. Ditto with biology or even math. Just look at The Big Bang Theory: all the main characters and most jokes are associated with physics.
@I actually forgot the original subject of the thread.
TomCat26, the reason you're finding that a lot of writers are smarter than you is that in math and physics, some writers feel the need not to teach you, but to show they're smarter than you. If you want to study QM using advanced math, I don't know exactly what to recommend you, sorry. But if you know nothing of quantum physics, Feynman's lectures are (always) a safe bet to give you some solid ground before studying further.
Haha! Despite studying physics, I think our society and the media have a somewhat unhealthy infatuation with the "sexyness" of physics, giving less attention to other much more complex sciences like chemistry and biology. I mean, I think that an educated layman is aware that the two major areas of physics are quantum mechanics and general relativity, yet I don't know exactly the major areas of chemistry or important fields of research. Ditto with biology or even math. Just look at The Big Bang Theory: all the main characters and most jokes are associated with physics.
The major areas of physics are generally considered the following: Relativity, Condensed Matter, Particle/High Energy, Nuclear (not to be confused with things like Nuclear power plants), Optics, Biophysics, and Cosmology.
Thanks for the more thorough edited reply. Nice simplified description of fermions vs. bosons! Now I just need to sit tight and wait until someone wants to learn molecular toxicology or bioanalytical chemistry...
And someday when I choose a specialty I can lie in wait to answer those questions...
The major areas of physics are generally considered the following: Relativity, Condensed Matter, Particle/High Energy, Nuclear (not to be confused with things like Nuclear power plants), Optics, Biophysics, and Cosmology.
Sorry, should've been clearer. These are mostly areas of research, I agree. However, I meant "areas of physics" in the sense that quantum mechanics (should've written the Standard Model, actually) covers the electromagnetic, weak and strong interactions while General Relativity covers gravity. There're some little things missing (neutrinos and dark matter..), but the Standard Model and General Relativity are the two grand fundamental divisions of physics.
My favorite video of Feynman is where the interviewer asks Feynman to explain magnetism to him (reporter), Feynman responded how it wouldn't be possible because the reporter had nowhere near the level of an education to be able to do it. How even an undergraduate education in physics lets you only begin to understand it.
Makes me feel a little bit more important studying physics. Now I just want to know why people with undergraduate degrees in business can end up making more than people with doctorates in physics...where is our priorities?
I just started reading Physics of the Impossible by Michio Kaku, I don't have a deep understanding of science but I was able to understand what he was saying. There's also a documentary called "What the Bleep Do We Know Anyway?" which is pretty cool too.
I just started reading Physics of the Impossible by Michio Kaku, I don't have a deep understanding of science but I was able to understand what he was saying. There's also a documentary called "What the Bleep Do We Know Anyway?" which is pretty cool too.
"What The Bleep" is pretty infamous for its use of fringe and pseudoscience, but I still found it enjoyable. Just make sure you take it all with a large grain of salt, as most of the conclusions they draw aren't supported by mainstream science.
Kaku is a fantastic writer who has a great gift for bringing difficult concepts down to an understandable level. His book Hyperspace, while now fairly outdated, was a fascinating introduction to string theory. Visions was also very good, with a similar feel to Physics of the Impossible.
"What The Bleep" is pretty infamous for its use of fringe and pseudoscience, but I still found it enjoyable. Just make sure you take it all with a large grain of salt, as most of the conclusions they draw aren't supported by mainstream science.
Kaku is a fantastic writer who has a great gift for bringing difficult concepts down to an understandable level. His book Hyperspace, while now fairly outdated, was a fascinating introduction to string theory. Visions was also very good, with a similar feel to Physics of the Impossible.
Thanks, I'll check out those books after I'm done with Physics of the Impossible.
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This was my hang-up as well, but Tim's point about mass may be the key here. Would it be technically, formally correct to say that wave-particle duality ascribes wave-like properties to particles, but not necessarily vice-versa? I think we may be conflating it to mean "all things are both waves and particles", which is too broad. The particle-like behavior of waves (i.e. photons from light) is established by the observations of quantized energy, right?
Light is massless and "is" a wave. It can behave as a particle, called the photon, which is also massless.
An electron has mass and "is" a particle. It can behave as a wave, but it's really a probability function that describes the possible locations of the particle, because a wave can't have mass.
Does that seem accurate?
Also, the probability waves in two dimensions as it propagates forward. Essentially, for a free particle, the probability wave is a plane that corkscrews as it travels through space.
For me in my modern class, the idea that it is the probability that waves and not the actual particle took me over a month to "get."
I think you are falling into the trap of thinking about this in a classical sense. Is inertia really an issue here? I really don't know.
I was merely pointing out that for light, its the electric and magnetic fields that are waving and for particles it is the probability that is waving. That is a distinction between them. A way to imagine it is that light is made up of what it is that is propagating whereas for a particle, it doesn't make sense to say that the electron is made up of probability.
VERY qualitatively, there're only fields, but because these fields are quantum, they cannot have any intensity. Instead it must always be a multiple of a certain quantity called the quantum of the field. A particle is simply a ripple (or "local excitation") of the field that has that minimum value of intensity and it kinda looks like a classical particle, but not quite. So the photon is a ripple in the photon field (also called electromagnetic field), the electron is a ripple in the electron field, the Higgs is a ripple in the Higgs fields, the graviton should be a ripple in the gravitational field (but damn you gravity!), and so on for all elementary particles. With this plus math you get the behaviour associated with wave-particle duality and more.
The only problem is that it isn't cited but generally physics pages are kept quite up to date by bored grad students.
Is nonsense, and I should have gone to bed rather than post it, yes?
From an "intuition" standpoint (as much as intuition can mean anything here) that sounds about as reasonable as anything else in quantum mechanics.
The behavior is the empirically observed behavior.
The most useful math to predict what we observe is the math we use.
Why should any phenomena or "events" that occur on a scale far below what we normally experience follow any kind of analogy to anything we know well?
Why should a particle behave in any way "like a pingpong ball" or move in a "straight lines"? What does "straight line" mean anyway? It's at least as vision/human perception bound a concept as point particle, and may have no analog in reality. Heck what straight OR curved "line" occurs in the universe?
Does the concept of "continuous" (which is required for the concept of "line" ) even really mean anything other than a kind of estimation or way we parse information into a neat, single concept? Isn't everything composed of vast numbers of "discrete" things?
Images on an LCD TV screen are composed of discrete pixels that just have distinct values for their color. Concepts like lines & shapes don't really exist on that meta-universe of the TV. Must lines and the concepts of shape underly any meta-universe including ours?
It's strange. We acknowledge a billiard ball (or any solid thing) is not continuous, not round, but really composed of vast numbers of "particles" interacting with each others... Yet why do we insist on thinking of those "particles" as acting a little like our old concept of billiard balls? Especially when just 2 seconds ago, we already did away with the concept of a billiard ball as meaningless.
So the whole universe might be a bunch of fields and particles are just manifestations of those fields and act nothing like billiard balls? Cool.
I'm actually quite shocked at how many people posted. For now I'm just going to take a look at some of the links posted. I haven't seen any nearby and cheap community colleges that offer the class just yet.
I'm actually looking to get into the mathematics of quantum mechanics rather than word-based conceptual explanations of the quantum level--which is why I've been starting with Lagrangian mechanics.
So far I've been trying to read through this text on path integrals. At this point I can say I have a reasonable understanding up to page 7 after a month. LOL
My other deduction is that this field is populated by people far smarter than I. In anycase, the above text is far too dense for me because i don't have the background with Lagrangian mechanics. Right now I'm trying to figure out the Euler-Lagrange equation.
Does anyone have any thoughts/critiques on how to continue from here? Or if I'm even starting in the right place?
btw: a huge thanks to everyone for their suggestions. In particular to 1drop. That link looks like a great place to start hacking away.
Yes
Light is a classical wave, but it really is composed of millions of excitations of the quantum photon field. If you decrease the intensity of a light beam so that there're only a couple of photons, you stop being able to describe light as a classical wave and start being able to describe it as a bunch of billiard balls. Ok, quantum billiard balls, but still.
Why can't millions of excitations of the electron field add up to form a "classical electron wave", like light? Because electrons are fermions and photons are bosons, which is a fancy way of saying "Pauli says they can't". Fermions hate being close to each other, while bosons love it.
And mass plays no role. Having mass doesn't make something less wavy and more particly.
@dcartist
Turns out that quantum particles, the excitations of quantum fields, really do behave a LOT like "pingpong balls" (not completely, obviously). I kid you not, they travel in straight lines, occupy a very small region of space, bounce off of surfaces, can collide with each other, etc...
Haha! Despite studying physics, I think our society and the media have a somewhat unhealthy infatuation with the "sexyness" of physics, giving less attention to other much more complex sciences like chemistry and biology. I mean, I think that an educated layman is aware that the two major areas of physics are quantum mechanics and general relativity, yet I don't know exactly the major areas of chemistry or important fields of research. Ditto with biology or even math. Just look at The Big Bang Theory: all the main characters and most jokes are associated with physics.
@I actually forgot the original subject of the thread.
TomCat26, the reason you're finding that a lot of writers are smarter than you is that in math and physics, some writers feel the need not to teach you, but to show they're smarter than you. If you want to study QM using advanced math, I don't know exactly what to recommend you, sorry. But if you know nothing of quantum physics, Feynman's lectures are (always) a safe bet to give you some solid ground before studying further.
The major areas of physics are generally considered the following: Relativity, Condensed Matter, Particle/High Energy, Nuclear (not to be confused with things like Nuclear power plants), Optics, Biophysics, and Cosmology.
And someday when I choose a specialty I can lie in wait to answer those questions...
Sorry, should've been clearer. These are mostly areas of research, I agree. However, I meant "areas of physics" in the sense that quantum mechanics (should've written the Standard Model, actually) covers the electromagnetic, weak and strong interactions while General Relativity covers gravity. There're some little things missing (neutrinos and dark matter..), but the Standard Model and General Relativity are the two grand fundamental divisions of physics.
Makes me feel a little bit more important studying physics. Now I just want to know why people with undergraduate degrees in business can end up making more than people with doctorates in physics...where is our priorities?
"What The Bleep" is pretty infamous for its use of fringe and pseudoscience, but I still found it enjoyable. Just make sure you take it all with a large grain of salt, as most of the conclusions they draw aren't supported by mainstream science.
Kaku is a fantastic writer who has a great gift for bringing difficult concepts down to an understandable level. His book Hyperspace, while now fairly outdated, was a fascinating introduction to string theory. Visions was also very good, with a similar feel to Physics of the Impossible.
Thanks, I'll check out those books after I'm done with Physics of the Impossible.