This reminds me a lot of the observation that the double-slit experiment still produces interference patterns when you send particles instead of waves, and them even when you send those particles one-by-one in order to exclude the possibility of inter-particle interference.
The dark side of light: negative frequency photons
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Re: The dark side of light: negative frequency photons
#22The interesting bit is that solving the equations gives you a solution with a negative frequency. Generally those negative frequencies are ignored because for most people a negative light frequency doesn't make sense. But if you extend the analysis further you get a positive frequency light out of interactions with that negative frequency light. And the paper talks a bit about observing those second order effects: "H…
At the turn of the 19th century, physicists were quite sure that they had a complete model of the universe, with just two minor unsolved problems: The aberration of light / michelson-morley experiment (which required the theory of relativity to explain), black body radiation (which was eventually explained by quantum mechanics). Actually solving these unsolved problems turned physics on its head. Negative frequency l…
Those examples were deviations of reality from prediction/model. This is sort of the opposite -- the model predicts negative frequency light but we ignore this because it doesn't match what we thought reality was doing. Now we see that there is some tangible real-ness to these solutions. It may have interesting applications, but it wouldn't require us to change the theory (since the theory already predicts it correctly).
Re: The dark side of light: negative frequency photons
#23I still don't get what a negative frequency is. The frequency is the number of times something happens in a given amount of time. Would a negative frequency be the number of events that were expected to happen but didn't? If so, how could this be differentiated from an error in our expectations.
Physics often uses the sign of a frequency to indicate the direction of travel with regard to a reference frame. E.g. 2 Hz is a wave oscillating two times per second and travelling to the right, -2 Hz is the same travelling to the left. In some cases direction isn't really meaningful (standing waves, or the height or pressure of a medium as seen by a stationary observer). In others, the direction of propagation can b…
For me, this is easiest to see through the equation Velocity = Frequency x Wavelength. Negative frequency is algebraically equivalent to negative wave velocity (which already means opposite direction), or negative wavelength (which already means opposite direction). There are several different ways that you could try to interpret "negative frequency," but by shuffling the negative sign around it becomes clear it must be equivalent to a wave of the same absolute frequency, where the wavelengths point the other way.
Re: The dark side of light: negative frequency photons
#24does this open the door to possibly traveling back in time?
Re: The dark side of light: negative frequency photons
#25Earlier quoted context omitted.
Not quite. A wave going left forward in time is equivalent to a wave 'going right' but backwards in time. Since it is further right in the past than now, it is actually going left. There's a lot of similar effects in Physics, especially with time and/or antimatter.
Save me the trouble an learn some basic physics. Read Jackson's Classical Electrodynamics, Chapter 7. If it's too complicated for you, read about waves. See how they propagate in time and space, and pay special attention to what happens to the equation when you change the sign of t. If it's too difficult to imagine, try plotting using a program. And anti-matter is not matter travelling backwards in time. See my post…
Could you be more condescending?
More seriously, explain to me how making the wave travel backwards isn't the same as changing the sign of t. Wave movement is linearly based on t.
Re: The dark side of light: negative frequency photons
#26Earlier quoted context omitted.
Not quite. A wave going left forward in time is equivalent to a wave 'going right' but backwards in time. Since it is further right in the past than now, it is actually going left. There's a lot of similar effects in Physics, especially with time and/or antimatter.
Save me the trouble an learn some basic physics. Read Jackson's Classical Electrodynamics, Chapter 7. If it's too complicated for you, read about waves. See how they propagate in time and space, and pay special attention to what happens to the equation when you change the sign of t. If it's too difficult to imagine, try plotting using a program. And anti-matter is not matter travelling backwards in time. See my post…
From just the book title, I'd like to point out that we have something known as Quantum Mechanics nowadays.
Re: The dark side of light: negative frequency photons
#27Earlier quoted context omitted.
Save me the trouble an learn some basic physics. Read Jackson's Classical Electrodynamics, Chapter 7. If it's too complicated for you, read about waves. See how they propagate in time and space, and pay special attention to what happens to the equation when you change the sign of t. If it's too difficult to imagine, try plotting using a program. And anti-matter is not matter travelling backwards in time. See my post…
Could you be more condescending? More seriously, explain to me how making the wave travel backwards isn't the same as changing the sign of t. Wave movement is linearly based on t.
Are we talking about the same thing?
I'm talking about particle waves, or wave functions of particles, not a function which satisfies the wave equation (a photon happens to satisfy the wave function, but I'm trying to be general here) and with frequency, I mean energy. Try changing the sign of t in Schrodinger equation and see if it simply amounts to changing the sign of your momentum vector or not.
Re: The dark side of light: negative frequency photons
#28Earlier quoted context omitted.
Save me the trouble an learn some basic physics. Read Jackson's Classical Electrodynamics, Chapter 7. If it's too complicated for you, read about waves. See how they propagate in time and space, and pay special attention to what happens to the equation when you change the sign of t. If it's too difficult to imagine, try plotting using a program. And anti-matter is not matter travelling backwards in time. See my post…
From just the book title, I'd like to point out that we have something known as Quantum Mechanics nowadays.
...which unfortunately doesn't cover a photon.
I think you meant quantum electrodynamics or quantum field theory.
Re: The dark side of light: negative frequency photons
#29How exactly would light at "negative green" frequency be perceived by an eye/camera, when mixed with an equal amount of regular green? Would it cancel out, would the negative light have no effect, or would the powers add constructively?
The article doesn't indicate what the physical manifestation of negative-frequency wave would be. It only reports the observation of a positive-frequency wave that seems to require the transient existence of a negative-frequency intermediate.
This is similar to how particles like the Higgs boson are not directly detected in particle accelerators, but are inferred from the directly-observable particles that they produce. The difference is that physicists are (I think) pretty sure that the Higgs actually physically exists, if only for a short time, while the same is not clear for the negative-frequency intermediate wave described here.
Re: The dark side of light: negative frequency photons
#30I still don't get what a negative frequency is. The frequency is the number of times something happens in a given amount of time. Would a negative frequency be the number of events that were expected to happen but didn't? If so, how could this be differentiated from an error in our expectations.
Physics often uses the sign of a frequency to indicate the direction of travel with regard to a reference frame. E.g. 2 Hz is a wave oscillating two times per second and travelling to the right, -2 Hz is the same travelling to the left. In some cases direction isn't really meaningful (standing waves, or the height or pressure of a medium as seen by a stationary observer). In others, the direction of propagation can b…
So is this saying that a portion of the waves of energy are reflected back towards the source, that this energy has a negative frequency, and that it has an effect that has been elusive because it has little chance to interact with the positive frequency waves? I'm curious what some of the implications might be.