The interference pattern from a double slit is (essentially) the Fourier transform of the spatial pattern of the slits (integrating over a complex exponential in space), so it would make sense that it would be true in time as well. But I also am coming at this from an electrical engineering perspective where we love to apply the Fourier transform.
I was thinking the same thing. You don't need to invoke quantum mechanics to understand this, you can get the same result from classical electromagnetism and Fourier transform theory.
Maybe the situation can be explained easier. What is important - and when thinking about it, should wonder more people - is the question why light is actually bending at the two splits in the classical experiment. Because this makes the result clearer. The reason why a laser beam can behave like a ray until it hits the split and afterwards like a wave, is the Heisenberg uncertainty principle. The moment you define the location with high precision, the more you mess up the impulse. Thus, with the light passing a very tiny (certain) split, you create an impulse pretty random (uncertain). That is why suddenly the light can change the direction and move to the "side" instead of continuing its former trajectory. It is then when it can interact with another wave (even with its own) and get "diverted" (simplified speaking). With the temporal splits, it is the same. The shorter the impulse of the photon is, the more specific its location is defined. However, that gives a more random impulse. This is already well documented for single impulses. A "pure" red light (or laser of a single wavelength) in super short impulses (e.g. photons of synchrotron emitters) is located at a certain location and thus changes colors - since a different (uncertain) impulse means an uncertain energy. Another energy in light means another color. So if your light pulse is just short enough, it may change from red to green or so. This is not new, but might help understanding the next step. Like with the two waves in the spatial experiment, the two waves in short temporal distance can interfere with each other. This interferance is the pattern we see. Maybe that helps a bit.
Light acts as a wave. Waves have a size defined by their wavelength. Particles are much smaller, perhaps points in space. Light has energy and it takes time to propagate. Heisenberg uncertainty extends to energy and time. Seems clear to me
Great explaination of this really cool experiment. Also I like the addition of the motion graphics. Your videos are getting better and better. Great Work!
It definitely is a great explanation. I'm no slouch in physics and this experiment really fascinates me, but this is the first explanation after several videos that I actually understood.
The question I have is why does the amplitude of light not count towards C? When calculating distance traveled for the amplitude is ignored. Something of the light in a longer wavelength travels further than shorter ones (or vise versa?) , no?
There's no surprise about broadening the spectrum on short pulses of light, it's similar result to when you do a fourier analysis on short pulse of sound - even if the sound itself is constant pitch at single frequency, the transition from "no sound" to "sound" and back introduces whole spectrum of sound frequencies that need to add up to form such a pulse. I'm somewhat curious how they arranged things for the two pulses to interfere, though. So It could be equally interesting to see the description of the instrument they used to detect the pulses and different frequencies of the result.
The image at 8:01 showing the response for a single time slot is surprising. Based on the same Fourier intuition as you have for sound, i would have expected a sinc pattern in that case too. I am not sure if that’s a simplified image for the purpose of vulgarisation or if it is part of the original experiment.
@@fvsfn agree with your comment. Maybe expect a sinc()^2 function. I guess what’s happening is the electric and magnetic field of the packet of photons is getting truncated causing the broadening in frequency as expected using Fourier theory. In the case of two (or more) temporality close pulses we are seeing interference/interaction between the broadened frequency electromagnetic fields of the two pulses as a result of them also being spatially very close together. I am probably being to simplistic but that seems to make sense?
exactly. because then the inpput pulse must be a gaussian. But two gaussians interfering should give another gaussian, so the simplified fourier approach might not be the whole story
I think you've hit on this precisely - the on / off of the pump laser defines the frequency bands - the on/off of the pump laser behaves exactly like you expect to get if you put a square wave through Fournier analysis(which effectively the on/off of the pump laser is). So something to ponder - either this is bogus and not really showing what they propose, or maybe it gives us a deep insight into the time and space interference and see if / how it relates to frequency interference via a fournier analysis. It would be extremely cool if we could correlate the infamous double slit experiment to fournier analysis, and potentially other frequency manipulation / analysis tools such as Laplace frequency transforms.
The Heisenberg uncertainty equation is usually written as (delta-x)(delta-p)>h/2*pi but you can also easily rearrange the Heisenberg equation so that, rather than position and momentum, it instead refers to energy and time. That is (delta-E)(delta-t) on the left side but remember that a photon's frequency is directly proportional to its energy (E=hf). So, in the traditional double slit experiment the delta-x is confined to one of two slits so the uncertainty in the lateral momentum must increase (two probability waves spread out and form a spacial interference pattern). From the (delta-E)(delta-t) point of view if you confine the (delta-t) to two time slits, then a similar thing must happen except now the two uncertainty "waves" are in the E=hf frequency. This creates two interfering frequencies and the associated beat pattern that is observed.
This is a fascinating and well-done explanation, but my brain keeps yelling, "Aren't these just Fourier transforms stretching wave packets? And similarly, doesn't the frequency spread for the same reason that sharply banging a gong produces loads of frequencies?" Yes, there is time uncertainty, but doesn't that also stretch the wave packets in length, allowing a more mundane explanation? I loved the potential for that femtosecond cutoff; that's one of those nifty new-tech enables that could go in very unexpected directions. Very cool.
The ‘photon’ doesn’t go through both slits (in space or time), the ‘photon’ is the absorbed (detected) state. The wavefunction is what goes through both slits, either because it is dynamic while spacetime is fixed, or (more likely) because it is fixed while spacetime is actually dynamic.
@@strangevideos3048 not as a real thing per se, but as a metric to measure how mass energy density affects itself yes. how else can you explain the effectiveness of Einstein's equations in GR?
Yes that way of thinking is waaaaay esier than "the particle is in multiple places at the same time": particles propagates as waves and interact as corpuscles, although in this particles case I am unable to see how an interference pattern can appear at "frequency space". Besides, the photon wave reaches the plastic screen at some particular moment, and hence, how would "pass and not pass" at the same time?
@@anywallsocket Hahah true, but because I can imagine the wave spreading out in space, not in time, and even less in "frequency". Can I somehow imagine the wave in "spacetime"? Not intuitively but I can make, kinda, maybe, peace with it, but in frequency? I can't visualize it.
That is very interesting. I am very interested in the progress towards optical computers. I see a future where a computer is a specially grown crystal where the processing path bounces back and forth through the crystal between switching devices, and through cavities to allow for processing time variations. This will give better protection against “jamming” of computer operations. More funding to your field!
Completely missed the point... This is just equivalent to the creation of spectral "sidebands" on a radio frequency carrier in case of amplitude modulation at frequencies not very much smaller than the carrier frequency. The probe laser represents the carrier with long coherence length and the femtosecond double pulses create an amplitude modulation which creates the optical sidebands in the spectral domain. And because of the longer coherence length they of course(!) overlap to create the optical spectrum of a double pulse. This, in fact is trivial, just check the well-established "pulse shaping in frequency domain" technologies. There even are holograms with spectral properties to create pulse sequences from a single readout pulse or vice versa. This was already demonstrated back in the 90ties, when femtosecond lasers became available... Just a consequence of the optical Fourier transform from time to frequency and back.
How do we know that what we are seeing is not just an effect of the pump laser light interacting with the probe laser light? The analysis proceeds as if the probe laser light is not even encountering the pump laser light, where in fact they are coincident on the surface...
Wow, that's a mind-bender. Btw, in the sound world we call those additional frequencies sidebands, and they are like little reflections of the carrier.
So the take away is that we can switch ITO incredibly frequently.....cool. And that interaction with the ITO surface modifies the probe beam.....kind of squishing it out. Got it. Super concise yet comprehensive explanation. Thanks!
What about the reaction time of the sensor that “reads” the incoming light? Could it just be that the material the sensor is made out of is entering a harmonic with the light and “re-releasing” it at a different frequency, only to get trapped and “re-read”? Like how atoms release infrared to describe heat? Maybe this is just the “heat equivalent” of a harmonic. This could just describe the interaction between light and matter, not what light actually is (particle, wave, wave-particle). The regular double slit experiment’s harmonic function would just be based on the size and distance the slits are from each other. Either way this interaction could be very valuable if understood fully. I can imagine a “light calculator” by varying the size (or duration of pulses for this experiment) of each slit against the other and summing or running other algorithms with the results.
The crossover of these concepts with acoustics is something I really love. I've often wondered whether an implementation of time-reversal to the double slit experiment is possible. Christ knows which way it would be done; maybe there isn't one.
Fascinating! Well explained, too. All the information is there; I just had to watch it a few of times. Of course, it helps to understand the classic double-slit experiment, where an interference pattern still emerges if individual photons are sent through, the photons being said to interfere with themselves. In the new experiment, however, it's the stretched-out frequency range of the different pulses that interfere with each other in time. I'm not a physicist, but could it be that in the classic experiment, the individual photons are actually also interfering with each other in time, as opposed to with themselves? This even seems to make more sense of the delayed-choice quantum eraser experiment, where turning on the which-way detector "in the future" causes the interference pattern to disappear "in the past." Maybe which-way detectors prevent pairs of photons from interfering with each other in time. But, surely I'm not the first one to have thought of this.
if you think about it the probability of two photons sharing the same exact instantaneous phase should be vanishingly small, so if another photon appears to fit the same description as a pair its because to begin with all you were describing was one big photon called the EM field
Think of a photon or any other particle as a wave that propagates throw space but that it's "absorbed" in a very particular location as a corpuscle with a different probability for each location. The idea of "a single corpuscle being in all locations at the same time and whose superposition effects follow wave mechanics" is a more complex way of saying: "the particle propagate as a wave".
I work in the entertainment lighting industry. In the last 10 years the shift to using LED lighting has changed the industry. LED's tend to use high frequency pulses to simulate dimming. We often manipulate the frequency at which those pulses happen for different effects or to help us work with cameras shutter speeds. When we change the frequency at which pulse happen there is often a color shift that happens. I wonder if this is why.
I'm not even sure what it means, interference in the frequency domain. Or how that could come about from 2 pulses that do not overlap in time. If you want to study these phenomena, you need some kind of grating to separate the different frequencies, which introduces path length differences. In 2.3 ps, light only travels 0.7mm, so part of these pulses might actually overlap temporally at the detector if you don't take extreme care to avoid this.
@@earthone777 But wouldn’t that be the equivalent of merging the two slits into one for the original double slit experiment? The purpose of this experiment is to vary the time domain, not the physical
@@earthone777 well, as in the video the light pulses are the “slit equivalent” in the classic experiment. Since it is much more difficult to vary the physical properties of the original experiment (size of the hole, and distance between them), if this experiment has a correlation to the original double silt experiment then we could vary these parameters instantaneously. This means that if we ever find an algorithm to use to get meaningful results from the variation of these parameters, we could literally make a computer that runs on light.
@Vizec I watched the video. I'll rephrase, what is the purpose of putting effort into this when there are more important things happening in the world. This is pretty pointless when in comparison. Why do we need a computer that runs on light. .. we don't need the matrix.
Clear and concise, very well explained. It's exactly what I understood from the little data from the experiment post. I did not understand, however, what the material has to do with the change in frequency of the reflected beam. As far as I know, in theory the reflected energy is conserved. If so, where did that energy go after the temporary interference?
Well, yes, the energy is conserved, however, the switching of the material, even though is extremely fast, is not instantaneous, thus creating a sort of reflecting gradient for the reflected beam to bounce off of; the "head" of the reflected beam penetrates a bit deeper into the material before it is reflected, than the "tail" of that switched length of beam. This gradient is what they referred to as "stretching like a spring would", essentially splitting that portion of the beam into multiple wavelengths/ frequencies corresponding to the different states of reflectivity up until maximum reflectivity. The energy is thus split into these resulting beams like a gradient. I'm more curious of what the relationship is between the switching beam length and the switching time of the material...how does having longer switching beams change the result....surely the switching time would be the same but just the period of maximum reflectivity would be longer...how does this affect coherence and does it matter and how much it matters?!?!
@@marian-gabriel9518 If I have understood your comment correctly, the frequency change would occur because in those 10 ft of transition of the material between transparent and reflective, part of the infrared laser beam is reflected at different depths of the material. This would produce diffraction and consequently a change in frequency or energy. However, that energy loss would be almost negligible in that case. Also, how would you explain that that only happens when there are 2 reflected pulses? When only one is reflected, that is, a single slit, no change in frequency is appreciated. And as you say, why is this decay in the spectrum related to the separation in time of the slits? On the other hand, would this experiment be possible with a single photon setup? In that way, it would not be possible to attribute in any way the result of the experiment to the interaction with the material. They do not want to rush to their conclusions but I think it is a more important discovery than it seems. My opinion is that the time interference consumes a bit of energy, but I don't know where it goes. At the moment they only speak of "new domain" and technological potential, but they do not say anything about what this would imply in the study of particles and time within MC.
@@Razor-i4k Well, exactly right. I think the key to this is how do they get the two beams to sync. They mentioned "photon acceleration". Which my guess is the manipulation of the beams, in time, via the diffraction and that gradient, in one way in the reflective material, and then back, in the "sensor" prism, essentially making them "wait" for one another. And I'm guessing this properties of the reflective material and prism directly affect the time slits intervals and durations they can successfully use. But as you say...this has very interesting implications and would very much like to see more of this.
Or has the strength of the interference light been varied? It would seem to me that interference would be analog not digital regardless of the pulse. The material would have some period to become reflective and return to transparent. In the interim some variance in the penetration and reflection would be expected.
@@JohnKerbaugh If you were to look up terms like "Signal Mixing" or "Superheterodyne" from radio technology, you'll see what I was thinking of when I asked the question. I'd also want to see what happens when you vary the angle of the glass, just to make sure.
@@JohnKerbaugh That's not really what this experimental setup is doing. You have a [reflection] / [not reflection] that's oscillating at a specific frequency, the intention of which is to develop an interference pattern based on time lag rather than just a spatial relationship. However, I can't shake the idea that, during the [not reflection] phase of the oscillation, there's a feature of refraction that's creeping into the experimental results. There's no reason I can think of in which anything remotely similar is happening on an astronomical scale. I think I know what you're thinking, but the relationship under study in this experiment isn't going to refine our understanding of redshift factors.
2 thoughts. 1) what if the light "spreads" going through the slit because it bounces off the walls of the slit? Even if the slit was made out of a single atom thick material the thickness of 1 atom is still much greater than the size of a photon, so the experiment isn't "clean". 2) What if the ITO changes the color of reflected light during the change of it's transparent/reflective state?
@8:00 What I do not understand, where does the energy for the broadening of the frequency band come from ( E= h*f )? And what happens to the laser-beam, that activates the In2O3*SnO2? Does it change its frequency ?
I've got a hunch that this could lead to the number of point particle counts for a certain beam, this would allow for an equation similar to electrical amperage. Perhaps a collapse of frequency can be found, a null phase in matter reflection, aka, invisibility.
This is great! I love hearing about bleeding edge experiments. Just like when the laser was 1st theorized. It took a long time, but where would we be without them?
6:24 wait a minute - isn't laser just a single frequency of light? the splitting into different wavelengths doesn't make sense to me (as there is only one - single colour).... or is the laser some kind of composite of different wavelengths from start? I know from school that travelling wave can change inensity and phase but never the frequency. Even if frequency somehow changed (the "spring effect") then it would be still just one frequency, only shifted, wouldn't it? Where all the colours come from? Or is it composite of multiple beams over time?
I have been asking channels to convey the below experiment. I hope you convey to them. Since presence of electron detector causes it to behave like wave or particle. Try this What if we put two rows of double slits row 2 after row 1. Row 2 double slit are made in a way that it matches the peak wave interference pattern on screen if there was only one double slit. So in this experiment the screen becomes double slit row 2. With all permutations and combinations. First experiment having no electron detector in row 1 and row 2, second experiment with only row 1 having electron detector, third experiment with only row 2 having electron detector finally last experiment with row 1 and row 2 having electron detector. Just a thought, have we tried this??
How is this not a perfectly conventional finding, known to electrical engineers for at least a century? If you take a continuous carrier and then you chop it on and then off, one time, so it has a finite duration, you will broaden the spectrum. If you chop it on and off periodically, you'll get a spectrum centered at the carrier frequency, with peaks occurring on either side of the carrier frequency, shifted by at multiples of the "chopping" frequency. This is a variation of a basic electronics demo - which I first saw demonstrated nearly 40 years ago - that uses a modulated carrier and a spectrum analyzer. Is there something more to this, that a straightforward Fourier analysis would not have predicted?
Firstly, a very well put video. I am still thinking this is a better version of double slit in space and not time. Just because the timing of slits is considered the interference is still happening in space.
This is all very interesting, but what really caught my ear (because I could actually understand it) was the bit about using the ITO to gate one laser signal with another. That's an AND gate if the output comes from the reflected signal, or using both outputs and one input always on, a complemented NOT gate, i.e. given signal A there is an A and a ~A output, like some kinds of flip flop. If you have AND and NOT (or just NAND for that matter) you can compose any logic gate from it. You only need electronic components for the equivalent of +5V (i.e. always on) and probably the clock signal, and you've got a full photonic computer. Am I missing something, or are photonics right around the corner?
Its unclear if this interference is a byproduct of the probabilistic absorption and emission of light by electrons in the reflective material or the light waves over time intervals in space 😵💫
@cyrilio it's a waste because there are world conflicts happening now that could use this amount of attention and effort in order to improve those situations. The world is falling apart but No scientists are worried about the freekin double slit experiment being performed in a new dimension! .. They're fooling you people.
The way I look at this type of discovery is for me to accept that time itself oscillates, but with some kind of overall forward momentum by our perspective. I think this could be what is happening with Time-Crystal oscillations. If true, then this would mean that time iterates back through itself at least once, if not more than once. Of course, this would mean that time's first-pass physics might be different than time's iterated physics, thus interference patterns should expectedly emerge in some probabilistic manner depending on the number of iterations and other such (random-ish) neighboring iteration contributions.
Would the behaviour be similar or related for e.g. a (very) quickly rotating disc with slits arranged and timely interacting in certain configurations?
This experiment would be interesting when checking the result with a single photon, which I think is not possible today in the experiment in the video. Also because it would be possible to put sensors in the slits or reflectors of the disc, being able to check the validity of the "which way" information hypothesis. In any case, how will you check that the rotation speed of the disk is almost absolutely constant?
At the end of your vid "the future changes the past" comment....I think I caught Sir Roger Penrose sayings something similar a few months back. It certainly sparked a lot of thought about it from myself.
I'm surprised that the Heisenberg uncertainty principle wasn't mentioned. The smaller and more precise the time interval the broader and more uncertain the frequency becomes.
Because The HUP is only really noticeable near the Planck scale, which is around 1e-43 (10^-43) seconds. The experiment deals with times at the 1e-12 (10^-12) second level (picoseconds), which is 31 orders of magnitude larger.
*About 20 years ago, there was an experiment of this double slit experiment* using SINGLE photons. This EU group shot a single photon a second and after a week, they got the same interference pattern as if they shot countless photons per second. The theory was that the photons was either (1) interacting with photons from another dimension (2) interacting with photons from foward/backward in time.
Or 'sideways' in 'time.' My theory is there are multiple time vectors, but physics has written the math as if there's only one. D = Delta T meaning there's as many time axes as space dimensions.
@@johnsmith1953x I did a little math around it in my book (unreleased so far) that indicates we are only 'partially sampling' time. It's different but analogous to Many Worlds interpretation of quantum physics. Regardless of how many vectors, it seems we evolved to only perceive one 't'.
If you have slits in a card, it is like a doorway which has thickness. This means that photons could ricochet off the sides of the slits and produce the patterns.
Can you explain what the detector is like? You said it splits the frequencies on the light pulses much like a refractive prism would. Can you (or anyone else) provide me with more details about it? I'd be very much interested in learning more.
they probably used a spectroscope, which typically uses a diffraction grating to split light into a spectrum. i don't entirely understand how it works but the effect looks similar to a prism
What I'd like to know is if the pulse laser just shot a single photon at a time, would you still see the quantum probabilistic interference pattern? Like in the classical two slit experiment. Of course, I'm guessing you would.
@@Littleprinceleonsomebody got the laser names wrong, either you or op. I think op means can the signal laser fire only one photon and the control laser can do whatever it does
I think that is not possible today. Imagine how difficult it must be to produce a single photon right in the time window in which the slit "opens". Or in other words, synchronize the production of the single photon with the pulse of the other laser.
When I was 14, at school, I proposed that the Double Slit experiment be conducted with electrons in vacuum apparatus of some kind. The idea behind that was to fire electrons one at a time, and compare that interference pattern (if any) with one made earlier via streams of electrons. I believe that experiment has now been conducted but using light rather than electrons, even though the latter are easier to manipulate!
Question - is this related to Fourier analysis and the Heisenberg uncertainty principal ? The way the spectrum of frequencies is broadened as the time between pulses gets smaller? If so, would this be another way to explain/ understand the process? Thank you
One fact that really blows my mind is that light travels at lightspeed so technically relative to the photon no time passes between it's creation and absorbtion. It just exists and it doesn't even realize it was reflected by some femtosecond-material thingy 😂 It's so mindblowing how something can exist outside and inside of time at the same time 😊😅😂
@komivalentine3067 Thank you. I think this comment has helped me understand the experiment results a bit better (perhaps) - In my head, I feel like "how can the 2nd set of photons interact with the first set of photons because some time has passed in between?" but the photons would just say "Time passed? When? We've been here all along!" @@colinyesutor2600 I think you are using two different definitions of the English word "light" rather than talking about the same thing - as in the original comment is talking about light the electromagnetic phenomenon and you are talking about light as in goodness or godliness (unless you are suggesting that you believe that God is an electromagnetic wave which would be unusual, easily disproved and it would be unclear why an electromagnetic wave would be worthy of praise). This experiment makes no comment on God's existence. TLDR: Words can have many different meanings.
Ok so when I saw the title and before watching the video, I thought the experiment was going to discuss the standard double slit method, but "delay" each pulse by varying the time between them. In other words, would there be any change in the interference pattern if you waited a day between pulses. Now I know that firing one photon at a time can be achieved now. This sort of delay(hour, day, week etc) between each pulse or single photon will take ages to build up a visible effect. So here's my question. Is the standard double slit interference pattern affected by time in the manner I described?
The time taken for the Kerr reaction, as the double slit an actual physical location? If so; how long does it take for the Kerr process to occur, vis the strike point, of the probe laser. As double slit implies different locations, with the speed of the Kerr effect being so fast the two positions must occur at different times? Anyway good vid I enjoyed especially the time measurements.
Ok, the spatial experiment, shows light to be a wave, but also a particle when the incoming photons are measured first and the interference pattern collapses. I didn't see (or possibly missed it in the video!) this phenomenon in the time experiment. Does this same "wave/particle" thing happen in time? Thank you!
What happens when the operation of the lasers is reversed? The pump laser stays on making the surface remain reflective and then use the same time intervals to shoot photons out of the probe laser rather than the pump laser? So instead of ALLOWING the photons to be reflected at certain times it would be ONLY a pair of photons that could be reflected to begin with. If i could phrase it another way. Instead of putting your finger on a running foscet to scatter the water what happens when your finger is already there and just 2 single droplets were released? Would the light behave the same way? If not to me it would suggest that light can move or influence other light o-o.
The way I look at this type of discovery is for me to accept that time itself oscillates, but with some kind of overall forward momentum by our perspective. I think this could be what is happening with Time-Crystal oscillations. If true, then this would mean that time iterates back through itself at least once, if not more than once. Of course, this could mean that time's first-pass physics might be different than time's iterated physics, thus interference patterns should expectedly emerge in some probabilistic manner depending on the number of iterations and other such (random-ish) neighboring iteration contributions. Thanks for the great explanation of this experiment and results. []:-)
@@Littleprinceleon If I remember correctly, this channel covers Frank Wilczek's predictions of Time Crystals' likely existence, and as later discovered by science teams. Otherwise, I have no favorite video suggestions, though there are many. Just search "Frank Wilczek and Time Crystals" and you'll likely find a factually scientific explanation. Basically, some of the same ones I've watched. Sorry I can't offer you more than this for the time being. Have fun with it, It's a fascinating subject.
Could this be mixing in their detector system? Is the detector fast enough to resolve this gap? This was my first time through the video. Wrapping my head around it.
The same is true of sound, I hear: Taking any note and repeating it at the frequency of another note will transpose it to that note. E.g. repeat 'C' 440 times a second and it becomes the note 'A'
I dont get it. Comparing to OG double slit experiment, why is this version not rather like if we just shot two particles two separate times through just one slit? Does the spectral device in the end just make one measurement from the two photons combined, or two measurements - one for each photon?
The interference phenomenon is instantaneous. If you do the experiment with 2 photons separated in time but only one time slit, the interference does not occur. The number of photons released in the experiment is independent of the result. The photons interfere with themselves only if you don't measure which slit it went through. That is, a minimum of two slits are needed. But at this moment I believe that the necessary technology does not exist to observe through which time slit the photons pass, which should be at a rate of 50%.
i havent yet seen this hypothesis..but i can only come to the conclusion that when you dont observe the double split youre not sending light at the light and when you are observing it you are sending light at it and the light colliding with each other coming from the detector is causing it to go from a wave to a particle. give me my Nobel prize !
Thank you, I'm still getting my head around this time interference. So far I think i've come to understand more about how wavelengths might be constructed as standing waves carried within wave functions of past and future photons wave cancelling themselves at regular spatial/temporal intervals but after that it gets very discombobulating and makes about as much sense a submerging a photon in a singularity, so information like this is amazing.
Disclaimer, I'm not a physicist or scientist, but I do sound engineering. My question is, how is this different than Frequency Modulation? To me it would seem that the pump laser is modulating the frequency of the probe laser with the period of its pulses. Therefore its adding upper harmonic complexities. I'd imagine the band pattern would change based on the change in the period between the pump laser pulses. In Frequency Modulation you have an operator oscillator of a specific frequency and then a modulator oscillator that changes the frequency of the operator frequency by the period of the modulator. When you increase the frequency of the modulator you increase the intensity and number of upper harmonic bands. So is FM or harmonic theory an application quantum mechanics in the time domain?
If quantum entanglement is real then it may be possible to predict everything which will eventually happen. This means that two distant civilisations may want to send each other a message but the transmitter will not only know the answer before they have sent the message but the receiver will know the question before the transmitter has sent it, maybe by billions of years.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
The interference pattern from a double slit is (essentially) the Fourier transform of the spatial pattern of the slits (integrating over a complex exponential in space), so it would make sense that it would be true in time as well. But I also am coming at this from an electrical engineering perspective where we love to apply the Fourier transform.
I was thinking the same thing. You don't need to invoke quantum mechanics to understand this, you can get the same result from classical electromagnetism and Fourier transform theory.
My guy we all aren't Einstein. This isn't english.
This paragraph made me feel more incompetent than any paragraph I've ever read and my iq is 120 lmfao.
@@ronaldbrody9 same here brother lol I feel really thick watching Ben's videos lol
@@ronaldbrody9 Do what I do, pace yourself !
If you get 200 more views today, 2/3 of it is me rewatching
And a few me.
But what colour would your view be
Why not finish watching that last time?
Same here.
@Johnald Wick hahahah😂
"Light travels through all possible paths at the same time" --- that is deep
Maybe the situation can be explained easier.
What is important - and when thinking about it, should wonder more people - is the question why light is actually bending at the two splits in the classical experiment. Because this makes the result clearer.
The reason why a laser beam can behave like a ray until it hits the split and afterwards like a wave, is the Heisenberg uncertainty principle.
The moment you define the location with high precision, the more you mess up the impulse. Thus, with the light passing a very tiny (certain) split, you create an impulse pretty random (uncertain).
That is why suddenly the light can change the direction and move to the "side" instead of continuing its former trajectory. It is then when it can interact with another wave (even with its own) and get "diverted" (simplified speaking).
With the temporal splits, it is the same. The shorter the impulse of the photon is, the more specific its location is defined. However, that gives a more random impulse.
This is already well documented for single impulses. A "pure" red light (or laser of a single wavelength) in super short impulses (e.g. photons of synchrotron emitters) is located at a certain location and thus changes colors - since a different (uncertain) impulse means an uncertain energy. Another energy in light means another color. So if your light pulse is just short enough, it may change from red to green or so.
This is not new, but might help understanding the next step.
Like with the two waves in the spatial experiment, the two waves in short temporal distance can interfere with each other. This interferance is the pattern we see.
Maybe that helps a bit.
Light acts as a wave. Waves have a size defined by their wavelength. Particles are much smaller, perhaps points in space.
Light has energy and it takes time to propagate. Heisenberg uncertainty extends to energy and time. Seems clear to me
Great explaination of this really cool experiment. Also I like the addition of the motion graphics. Your videos are getting better and better. Great Work!
Thanks! Right back at you 👍
It definitely is a great explanation. I'm no slouch in physics and this experiment really fascinates me, but this is the first explanation after several videos that I actually understood.
The question I have is why does the amplitude of light not count towards C? When calculating distance traveled for the amplitude is ignored. Something of the light in a longer wavelength travels further than shorter ones (or vise versa?) , no?
@@JohnKerbaugh light oscillates perpendicular to the direction of travel, so it doesn't really apply...
@@DrBenMiles this video's background music is not tacky and annoying enough
This is fascinating and the way you explain such a complex subject in a simple way is admiring
This is by far the best video I have ever seen anywhere on RUclips
There's no surprise about broadening the spectrum on short pulses of light, it's similar result to when you do a fourier analysis on short pulse of sound - even if the sound itself is constant pitch at single frequency, the transition from "no sound" to "sound" and back introduces whole spectrum of sound frequencies that need to add up to form such a pulse. I'm somewhat curious how they arranged things for the two pulses to interfere, though. So It could be equally interesting to see the description of the instrument they used to detect the pulses and different frequencies of the result.
The image at 8:01 showing the response for a single time slot is surprising. Based on the same Fourier intuition as you have for sound, i would have expected a sinc pattern in that case too. I am not sure if that’s a simplified image for the purpose of vulgarisation or if it is part of the original experiment.
@@fvsfn agree with your comment. Maybe expect a sinc()^2 function. I guess what’s happening is the electric and magnetic field of the packet of photons is getting truncated causing the broadening in frequency as expected using Fourier theory. In the case of two (or more) temporality close pulses we are seeing interference/interaction between the broadened frequency electromagnetic fields of the two pulses as a result of them also being spatially very close together.
I am probably being to simplistic but that seems to make sense?
exactly. because then the inpput pulse must be a gaussian. But two gaussians interfering should give another gaussian, so the simplified fourier approach might not be the whole story
I think you've hit on this precisely - the on / off of the pump laser defines the frequency bands - the on/off of the pump laser behaves exactly like you expect to get if you put a square wave through Fournier analysis(which effectively the on/off of the pump laser is).
So something to ponder - either this is bogus and not really showing what they propose, or maybe it gives us a deep insight into the time and space interference and see if / how it relates to frequency interference via a fournier analysis. It would be extremely cool if we could correlate the infamous double slit experiment to fournier analysis, and potentially other frequency manipulation / analysis tools such as Laplace frequency transforms.
The Heisenberg uncertainty equation is usually written as (delta-x)(delta-p)>h/2*pi but you can also easily rearrange the Heisenberg equation so that, rather than position and momentum, it instead refers to energy and time. That is (delta-E)(delta-t) on the left side but remember that a photon's frequency is directly proportional to its energy (E=hf). So, in the traditional double slit experiment the delta-x is confined to one of two slits so the uncertainty in the lateral momentum must increase (two probability waves spread out and form a spacial interference pattern). From the (delta-E)(delta-t) point of view if you confine the (delta-t) to two time slits, then a similar thing must happen except now the two uncertainty "waves" are in the E=hf frequency. This creates two interfering frequencies and the associated beat pattern that is observed.
...brilliant video!...incredibly difficult subject presented in a very clear, understandable way...helpful graphics too...
WOW.. the implications of this for future computing and quantum computing is absolutely incredible...I can't wait!!
Clean concise explanation 👌 Thank you for your work good sir
This is a fascinating and well-done explanation, but my brain keeps yelling, "Aren't these just Fourier transforms stretching wave packets? And similarly, doesn't the frequency spread for the same reason that sharply banging a gong produces loads of frequencies?" Yes, there is time uncertainty, but doesn't that also stretch the wave packets in length, allowing a more mundane explanation? I loved the potential for that femtosecond cutoff; that's one of those nifty new-tech enables that could go in very unexpected directions. Very cool.
The ‘photon’ doesn’t go through both slits (in space or time), the ‘photon’ is the absorbed (detected) state. The wavefunction is what goes through both slits, either because it is dynamic while spacetime is fixed, or (more likely) because it is fixed while spacetime is actually dynamic.
You believe in "spacetime" ? 😅
@@strangevideos3048 not as a real thing per se, but as a metric to measure how mass energy density affects itself yes. how else can you explain the effectiveness of Einstein's equations in GR?
Yes that way of thinking is waaaaay esier than "the particle is in multiple places at the same time": particles propagates as waves and interact as corpuscles, although in this particles case I am unable to see how an interference pattern can appear at "frequency space". Besides, the photon wave reaches the plastic screen at some particular moment, and hence, how would "pass and not pass" at the same time?
@@Peregringlk somehow you just agreed with me then lost the idea in the same post.
@@anywallsocket Hahah true, but because I can imagine the wave spreading out in space, not in time, and even less in "frequency". Can I somehow imagine the wave in "spacetime"? Not intuitively but I can make, kinda, maybe, peace with it, but in frequency? I can't visualize it.
That is very interesting. I am very interested in the progress towards optical computers. I see a future where a computer is a specially grown crystal where the processing path bounces back and forth through the crystal between switching devices, and through cavities to allow for processing time variations. This will give better protection against “jamming” of computer operations. More funding to your field!
So the crystal skull was a super computer??
@@woutmoerman711 grown by Nvidia
Haha…super expensive diamond processors…
06:24 what if you point pump laser at detector? how would that be different than reflected probe laser's light?
It's amazing... please make more detailed videos on this subject ....
Completely missed the point...
This is just equivalent to the creation of spectral "sidebands" on a radio frequency carrier in case of amplitude modulation at frequencies not very much smaller than the carrier frequency.
The probe laser represents the carrier with long coherence length and the femtosecond double pulses create an amplitude modulation which creates the optical sidebands in the spectral domain. And because of the longer coherence length they of course(!) overlap to create the optical spectrum of a double pulse.
This, in fact is trivial, just check the well-established "pulse shaping in frequency domain" technologies. There even are holograms with spectral properties to create pulse sequences from a single readout pulse or vice versa. This was already demonstrated back in the 90ties, when femtosecond lasers became available...
Just a consequence of the optical Fourier transform from time to frequency and back.
I like the phase change causing output of an interference pattern. The pattern can be controlled by the speed of the pulse. Rad.
How do we know that what we are seeing is not just an effect of the pump laser light interacting with the probe laser light? The analysis proceeds as if the probe laser light is not even encountering the pump laser light, where in fact they are coincident on the surface...
Wow, that's a mind-bender. Btw, in the sound world we call those additional frequencies sidebands, and they are like little reflections of the carrier.
So the take away is that we can switch ITO incredibly frequently.....cool. And that interaction with the ITO surface modifies the probe beam.....kind of squishing it out. Got it.
Super concise yet comprehensive explanation. Thanks!
I need to watch 2 times to understand, good video thanks brother
What about the reaction time of the sensor that “reads” the incoming light? Could it just be that the material the sensor is made out of is entering a harmonic with the light and “re-releasing” it at a different frequency, only to get trapped and “re-read”? Like how atoms release infrared to describe heat? Maybe this is just the “heat equivalent” of a harmonic. This could just describe the interaction between light and matter, not what light actually is (particle, wave, wave-particle). The regular double slit experiment’s harmonic function would just be based on the size and distance the slits are from each other. Either way this interaction could be very valuable if understood fully. I can imagine a “light calculator” by varying the size (or duration of pulses for this experiment) of each slit against the other and summing or running other algorithms with the results.
The crossover of these concepts with acoustics is something I really love. I've often wondered whether an implementation of time-reversal to the double slit experiment is possible. Christ knows which way it would be done; maybe there isn't one.
Fascinating! Well explained, too. All the information is there; I just had to watch it a few of times. Of course, it helps to understand the classic double-slit experiment, where an interference pattern still emerges if individual photons are sent through, the photons being said to interfere with themselves. In the new experiment, however, it's the stretched-out frequency range of the different pulses that interfere with each other in time. I'm not a physicist, but could it be that in the classic experiment, the individual photons are actually also interfering with each other in time, as opposed to with themselves? This even seems to make more sense of the delayed-choice quantum eraser experiment, where turning on the which-way detector "in the future" causes the interference pattern to disappear "in the past." Maybe which-way detectors prevent pairs of photons from interfering with each other in time. But, surely I'm not the first one to have thought of this.
if you think about it the probability of two photons sharing the same exact instantaneous phase should be vanishingly small, so if another photon appears to fit the same description as a pair its because to begin with all you were describing was one big photon called the EM field
@@SplendidKunoichi Lasers emit photons that are in phase. If they weren’t, they couldn’t for example be used to detect gravitational waves.
@@NiToNi2002 lasers emit photons randomly. That's why they are coherent. Look up bunching and anti-bunching
Think of a photon or any other particle as a wave that propagates throw space but that it's "absorbed" in a very particular location as a corpuscle with a different probability for each location. The idea of "a single corpuscle being in all locations at the same time and whose superposition effects follow wave mechanics" is a more complex way of saying: "the particle propagate as a wave".
Impressive!!! Thanks for the good explanation!
This is super amazing, but damn is it gonna suck when we run out of Indium
Brilliantly described. Thank you
I have pondered upon exactly this idea of double slit experiment in time and using light for logic... feeling scientist now😅
Happy to see Riccardo here, he was one of my lecturers at Imperial, very nice guy
I work in the entertainment lighting industry. In the last 10 years the shift to using LED lighting has changed the industry. LED's tend to use high frequency pulses to simulate dimming. We often manipulate the frequency at which those pulses happen for different effects or to help us work with cameras shutter speeds. When we change the frequency at which pulse happen there is often a color shift that happens. I wonder if this is why.
Wow.. so much thankful for this.. have been looking for what's next and new and exciting.. double wow..
I'm not even sure what it means, interference in the frequency domain. Or how that could come about from 2 pulses that do not overlap in time. If you want to study these phenomena, you need some kind of grating to separate the different frequencies, which introduces path length differences. In 2.3 ps, light only travels 0.7mm, so part of these pulses might actually overlap temporally at the detector if you don't take extreme care to avoid this.
Thank you. It should be passing through the slits simultaneously.
@@earthone777 But wouldn’t that be the equivalent of merging the two slits into one for the original double slit experiment? The purpose of this experiment is to vary the time domain, not the physical
@@_vizec I see. So the intention IS to separate instances. Soooo then whats the purpose of this?
@@earthone777 well, as in the video the light pulses are the “slit equivalent” in the classic experiment. Since it is much more difficult to vary the physical properties of the original experiment (size of the hole, and distance between them), if this experiment has a correlation to the original double silt experiment then we could vary these parameters instantaneously. This means that if we ever find an algorithm to use to get meaningful results from the variation of these parameters, we could literally make a computer that runs on light.
@Vizec I watched the video. I'll rephrase, what is the purpose of putting effort into this when there are more important things happening in the world. This is pretty pointless when in comparison. Why do we need a computer that runs on light. .. we don't need the matrix.
Clear and concise, very well explained. It's exactly what I understood from the little data from the experiment post. I did not understand, however, what the material has to do with the change in frequency of the reflected beam. As far as I know, in theory the reflected energy is conserved. If so, where did that energy go after the temporary interference?
Well, yes, the energy is conserved, however, the switching of the material, even though is extremely fast, is not instantaneous, thus creating a sort of reflecting gradient for the reflected beam to bounce off of; the "head" of the reflected beam penetrates a bit deeper into the material before it is reflected, than the "tail" of that switched length of beam. This gradient is what they referred to as "stretching like a spring would", essentially splitting that portion of the beam into multiple wavelengths/ frequencies corresponding to the different states of reflectivity up until maximum reflectivity. The energy is thus split into these resulting beams like a gradient. I'm more curious of what the relationship is between the switching beam length and the switching time of the material...how does having longer switching beams change the result....surely the switching time would be the same but just the period of maximum reflectivity would be longer...how does this affect coherence and does it matter and how much it matters?!?!
@@marian-gabriel9518 If I have understood your comment correctly, the frequency change would occur because in those 10 ft of transition of the material between transparent and reflective, part of the infrared laser beam is reflected at different depths of the material. This would produce diffraction and consequently a change in frequency or energy. However, that energy loss would be almost negligible in that case. Also, how would you explain that that only happens when there are 2 reflected pulses? When only one is reflected, that is, a single slit, no change in frequency is appreciated. And as you say, why is this decay in the spectrum related to the separation in time of the slits? On the other hand, would this experiment be possible with a single photon setup? In that way, it would not be possible to attribute in any way the result of the experiment to the interaction with the material. They do not want to rush to their conclusions but I think it is a more important discovery than it seems. My opinion is that the time interference consumes a bit of energy, but I don't know where it goes. At the moment they only speak of "new domain" and technological potential, but they do not say anything about what this would imply in the study of particles and time within MC.
@@Razor-i4k Well, exactly right. I think the key to this is how do they get the two beams to sync. They mentioned "photon acceleration". Which my guess is the manipulation of the beams, in time, via the diffraction and that gradient, in one way in the reflective material, and then back, in the "sensor" prism, essentially making them "wait" for one another. And I'm guessing this properties of the reflective material and prism directly affect the time slits intervals and durations they can successfully use. But as you say...this has very interesting implications and would very much like to see more of this.
Has the thickness of the coated plate been varied within the scope of the experiment yet?
Good question
Or has the strength of the interference light been varied?
It would seem to me that interference would be analog not digital regardless of the pulse. The material would have some period to become reflective and return to transparent. In the interim some variance in the penetration and reflection would be expected.
@@JohnKerbaugh If you were to look up terms like "Signal Mixing" or "Superheterodyne" from radio technology, you'll see what I was thinking of when I asked the question. I'd also want to see what happens when you vary the angle of the glass, just to make sure.
@@sirnukesalot24 Another thought came to me, if it is in fact time traversal, does the math add up to account for stellar distance traveled?
@@JohnKerbaugh That's not really what this experimental setup is doing. You have a [reflection] / [not reflection] that's oscillating at a specific frequency, the intention of which is to develop an interference pattern based on time lag rather than just a spatial relationship. However, I can't shake the idea that, during the [not reflection] phase of the oscillation, there's a feature of refraction that's creeping into the experimental results. There's no reason I can think of in which anything remotely similar is happening on an astronomical scale. I think I know what you're thinking, but the relationship under study in this experiment isn't going to refine our understanding of redshift factors.
2 thoughts. 1) what if the light "spreads" going through the slit because it bounces off the walls of the slit? Even if the slit was made out of a single atom thick material the thickness of 1 atom is still much greater than the size of a photon, so the experiment isn't "clean". 2) What if the ITO changes the color of reflected light during the change of it's transparent/reflective state?
Having light computers sounds super cool. Definitely a bright idea!
We got phones, there pretty light
@Jarno van der Zee I wonder how many people will understand the weight of your comment.
If its asleep it has no weight.
10:18 shouldn't the single pulse beam be a sinc then just like in the spatial case?
Does this prove the anisotropic speed of light, except that the speed is not static but rather a quantum wave function of possibilities?
Yes yes please more of this content. Capture the light with the trillion fps camera.
@8:00 What I do not understand, where does the energy for the broadening of the frequency band come from ( E= h*f )? And what happens to the laser-beam, that activates the In2O3*SnO2? Does it change its frequency ?
I've got a hunch that this could lead to the number of point particle counts for a certain beam, this would allow for an equation similar to electrical amperage. Perhaps a collapse of frequency can be found, a null phase in matter reflection, aka, invisibility.
Great channel. Thanks Ben!
This is great! I love hearing about bleeding edge experiments. Just like when the laser was 1st theorized. It took a long time, but where would we be without them?
6:24 wait a minute - isn't laser just a single frequency of light? the splitting into different wavelengths doesn't make sense to me (as there is only one - single colour).... or is the laser some kind of composite of different wavelengths from start? I know from school that travelling wave can change inensity and phase but never the frequency. Even if frequency somehow changed (the "spring effect") then it would be still just one frequency, only shifted, wouldn't it? Where all the colours come from? Or is it composite of multiple beams over time?
I have been asking channels to convey the below experiment. I hope you convey to them. Since presence of electron detector causes it to behave like wave or particle. Try this
What if we put two rows of double slits row 2 after row 1. Row 2 double slit are made in a way that it matches the peak wave interference pattern on screen if there was only one double slit. So in this experiment the screen becomes double slit row 2. With all permutations and combinations. First experiment having no electron detector in row 1 and row 2, second experiment with only row 1 having electron detector, third experiment with only row 2 having electron detector finally last experiment with row 1 and row 2 having electron detector. Just a thought, have we tried this??
Can you give a link to the paper itself?
How is this not a perfectly conventional finding, known to electrical engineers for at least a century? If you take a continuous carrier and then you chop it on and then off, one time, so it has a finite duration, you will broaden the spectrum. If you chop it on and off periodically, you'll get a spectrum centered at the carrier frequency, with peaks occurring on either side of the carrier frequency, shifted by at multiples of the "chopping" frequency. This is a variation of a basic electronics demo - which I first saw demonstrated nearly 40 years ago - that uses a modulated carrier and a spectrum analyzer.
Is there something more to this, that a straightforward Fourier analysis would not have predicted?
Firstly, a very well put video. I am still thinking this is a better version of double slit in space and not time. Just because the timing of slits is considered the interference is still happening in space.
This is all very interesting, but what really caught my ear (because I could actually understand it) was the bit about using the ITO to gate one laser signal with another. That's an AND gate if the output comes from the reflected signal, or using both outputs and one input always on, a complemented NOT gate, i.e. given signal A there is an A and a ~A output, like some kinds of flip flop. If you have AND and NOT (or just NAND for that matter) you can compose any logic gate from it. You only need electronic components for the equivalent of +5V (i.e. always on) and probably the clock signal, and you've got a full photonic computer. Am I missing something, or are photonics right around the corner?
What are the bandwidths of each band? How much did they change when the "slits" changed? What was the frequency of the lasers? More info plz?
Its unclear if this interference is a byproduct of the probabilistic absorption and emission of light by electrons in the reflective material or the light waves over time intervals in space 😵💫
Ahh the double slit experiment. What a throwback!
You kept my attention completely… Very clear and concise, and I understood everything you said
Great stuff. Thank you for creating this. Subbed.
Pausing before watching to point out yet another fabulously appropriate facial expression in thumbnail.
Also time is emergent from events. How do you factor this into the experiment?
Really does seems like a waste of money. There are problems in the world this could be used for.
@@earthone777 research in to fundamental physics is never a waste of money. These are the unknown-unknowns.
@cyrilio it's a waste because there are world conflicts happening now that could use this amount of attention and effort in order to improve those situations. The world is falling apart but No scientists are worried about the freekin double slit experiment being performed in a new dimension! .. They're fooling you people.
@cyrilio it's a waste of morality.
The way I look at this type of discovery is for me to accept that time itself oscillates, but with some kind of overall forward momentum by our perspective. I think this could be what is happening with Time-Crystal oscillations. If true, then this would mean that time iterates back through itself at least once, if not more than once. Of course, this would mean that time's first-pass physics might be different than time's iterated physics, thus interference patterns should expectedly emerge in some probabilistic manner depending on the number of iterations and other such (random-ish) neighboring iteration contributions.
Would the behaviour be similar or related for e.g. a (very) quickly rotating disc with slits arranged and timely interacting in certain configurations?
This experiment would be interesting when checking the result with a single photon, which I think is not possible today in the experiment in the video. Also because it would be possible to put sensors in the slits or reflectors of the disc, being able to check the validity of the "which way" information hypothesis. In any case, how will you check that the rotation speed of the disk is almost absolutely constant?
At the end of your vid "the future changes the past" comment....I think I caught Sir Roger Penrose sayings something similar a few months back. It certainly sparked a lot of thought about it from myself.
The classical outro music I love it!
TheFatRat - Xenogenesis
I'm surprised that the Heisenberg uncertainty principle wasn't mentioned. The smaller and more precise the time interval the broader and more uncertain the frequency becomes.
or more generally, the Fourier Transform
Because The HUP is only really noticeable near the Planck scale, which is around 1e-43 (10^-43) seconds. The experiment deals with times at the 1e-12 (10^-12) second level (picoseconds), which is 31 orders of magnitude larger.
*About 20 years ago, there was an experiment of this double slit experiment*
using SINGLE photons. This EU group shot a single photon a second and after a week,
they got the same interference pattern as if they shot countless photons per second.
The theory was that the photons was either (1) interacting with photons from another dimension (2) interacting with photons from foward/backward in time.
Or 'sideways' in 'time.' My theory is there are multiple time vectors, but physics has written the math as if there's only one. D = Delta T meaning there's as many time axes as space dimensions.
@@organicdoorbell5881 I've heard about that a decade ago and I'm still confused on the physical meaning of "extra" time dimensions.
Keep it simple. It interfere with itself.
@@johnsmith1953x I did a little math around it in my book (unreleased so far) that indicates we are only 'partially sampling' time. It's different but analogous to Many Worlds interpretation of quantum physics. Regardless of how many vectors, it seems we evolved to only perceive one 't'.
@@organicdoorbell5881 Then is it possible to go back in time that is a different "sideways" or parallel time rather than the current time?
Great work!
Great video. Cheers !
If you have slits in a card, it is like a doorway which has thickness. This means that photons could ricochet off the sides of the slits and produce the patterns.
Is this not still an experiment with light? Or can someone explain a little better how light can be a stand in for time? thanks!
WOW!!! Mind bending!
Can you explain what the detector is like? You said it splits the frequencies on the light pulses much like a refractive prism would. Can you (or anyone else) provide me with more details about it? I'd be very much interested in learning more.
i'm assuming its just a spectroscope
they probably used a spectroscope, which typically uses a diffraction grating to split light into a spectrum. i don't entirely understand how it works but the effect looks similar to a prism
Cool. Thanks for sharing.
What I'd like to know is if the pulse laser just shot a single photon at a time, would you still see the quantum probabilistic interference pattern? Like in the classical two slit experiment. Of course, I'm guessing you would.
Is the maximum amount of energy transferrable by a single photon enough to change the reflectivity of this indium-tin-oxide material?
@@Littleprinceleonsomebody got the laser names wrong, either you or op. I think op means can the signal laser fire only one photon and the control laser can do whatever it does
I think that is not possible today. Imagine how difficult it must be to produce a single photon right in the time window in which the slit "opens". Or in other words, synchronize the production of the single photon with the pulse of the other laser.
I wonder if you could use the color changes for encryption or use the reflection changes for a laser.
When I was 14, at school, I proposed that the Double Slit experiment be conducted with electrons in vacuum apparatus of some kind. The idea behind that was to fire electrons one at a time, and compare that interference pattern (if any) with one made earlier via streams of electrons.
I believe that experiment has now been conducted but using light rather than electrons, even though the latter are easier to manipulate!
I highly doubt it.
The potential is very exciting.
What will be the equivalent of quantum delayed choice experiment in time domain ?
That will make light to behave as particle not wave.
It might have been useful to talk about Fourier transforms in this video.
agreed, Im surprised it wasn't even mentioned
Question - is this related to Fourier analysis and the Heisenberg uncertainty principal ? The way the spectrum of frequencies is broadened as the time between pulses gets smaller? If so, would this be another way to explain/ understand the process?
Thank you
One fact that really blows my mind is that light travels at lightspeed so technically relative to the photon no time passes between it's creation and absorbtion. It just exists and it doesn't even realize it was reflected by some femtosecond-material thingy 😂
It's so mindblowing how something can exist outside and inside of time at the same time 😊😅😂
This is the best explanation for the existence of God, he is light and exists outside and inside space and time.
God is not light.
@@deltalima6703 To me he is. My Bible says he is. Don't sweat it.
@@colinyesutor2600 The more we understand about the universe, the less we need to rely on made up stories about imaginary friends.
@komivalentine3067 Thank you. I think this comment has helped me understand the experiment results a bit better (perhaps) - In my head, I feel like "how can the 2nd set of photons interact with the first set of photons because some time has passed in between?" but the photons would just say "Time passed? When? We've been here all along!" @@colinyesutor2600 I think you are using two different definitions of the English word "light" rather than talking about the same thing - as in the original comment is talking about light the electromagnetic phenomenon and you are talking about light as in goodness or godliness (unless you are suggesting that you believe that God is an electromagnetic wave which would be unusual, easily disproved and it would be unclear why an electromagnetic wave would be worthy of praise). This experiment makes no comment on God's existence. TLDR: Words can have many different meanings.
Ok so when I saw the title and before watching the video, I thought the experiment was going to discuss the standard double slit method, but "delay" each pulse by varying the time between them. In other words, would there be any change in the interference pattern if you waited a day between pulses.
Now I know that firing one photon at a time can be achieved now. This sort of delay(hour, day, week etc) between each pulse or single photon will take ages to build up a visible effect. So here's my question. Is the standard double slit interference pattern affected by time in the manner I described?
The time taken for the Kerr reaction, as the double slit an actual physical location? If so; how long does it take for the Kerr process to occur, vis the strike point, of the probe laser. As double slit implies different locations, with the speed of the Kerr effect being so fast the two positions must occur at different times? Anyway good vid I enjoyed especially the time measurements.
It said 10 femtoseconds in the video.
It looks a lot like typical nonlinear multiplication similar to mixing effects. You get a carrier, and the Sum and difference frequencies generated.
Ok, the spatial experiment, shows light to be a wave, but also a particle when the incoming photons are measured first and the interference pattern collapses. I didn't see (or possibly missed it in the video!) this phenomenon in the time experiment. Does this same "wave/particle" thing happen in time? Thank you!
By the way, how does that detector work? It sounds like it's just a prism, but is it more than that?
What happens when the operation of the lasers is reversed? The pump laser stays on making the surface remain reflective and then use the same time intervals to shoot photons out of the probe laser rather than the pump laser?
So instead of ALLOWING the photons to be reflected at certain times it would be ONLY a pair of photons that could be reflected to begin with.
If i could phrase it another way. Instead of putting your finger on a running foscet to scatter the water what happens when your finger is already there and just 2 single droplets were released? Would the light behave the same way? If not to me it would suggest that light can move or influence other light o-o.
The way I look at this type of discovery is for me to accept that time itself oscillates, but with some kind of overall forward momentum by our perspective. I think this could be what is happening with Time-Crystal oscillations. If true, then this would mean that time iterates back through itself at least once, if not more than once. Of course, this could mean that time's first-pass physics might be different than time's iterated physics, thus interference patterns should expectedly emerge in some probabilistic manner depending on the number of iterations and other such (random-ish) neighboring iteration contributions. Thanks for the great explanation of this experiment and results. []:-)
Could you please provide a/some good introductory video(s) on time-crystals?
@@Littleprinceleon If I remember correctly, this channel covers Frank Wilczek's predictions of Time Crystals' likely existence, and as later discovered by science teams. Otherwise, I have no favorite video suggestions, though there are many. Just search "Frank Wilczek and Time Crystals" and you'll likely find a factually scientific explanation. Basically, some of the same ones I've watched. Sorry I can't offer you more than this for the time being. Have fun with it, It's a fascinating subject.
Subscribed 😊
Could this be mixing in their detector system? Is the detector fast enough to resolve this gap?
This was my first time through the video. Wrapping my head around it.
So if they had a constant beam switching the material to be reflective there should only be one peak?
Does the lazer light that changes give off frequencies in ALL light frequencies? Does it go to gamma and infrared?
The same is true of sound, I hear: Taking any note and repeating it at the frequency of another note will transpose it to that note.
E.g. repeat 'C' 440 times a second and it becomes the note 'A'
I dont get it. Comparing to OG double slit experiment, why is this version not rather like if we just shot two particles two separate
times through just one slit? Does the spectral device in the end just make one measurement from the two photons combined, or two measurements - one for each photon?
The interference phenomenon is instantaneous. If you do the experiment with 2 photons separated in time but only one time slit, the interference does not occur. The number of photons released in the experiment is independent of the result. The photons interfere with themselves only if you don't measure which slit it went through. That is, a minimum of two slits are needed. But at this moment I believe that the necessary technology does not exist to observe through which time slit the photons pass, which should be at a rate of 50%.
The double slit freaks me out! Can you in how this links to retro causality? Please!
i havent yet seen this hypothesis..but i can only come to the conclusion that when you dont observe the double split youre not sending light at the light and when you are observing it you are sending light at it and the light colliding with each other coming from the detector is causing it to go from a wave to a particle. give me my Nobel prize !
Do we know what happens if we pass light through or reflect light on time crystals? What should we expect?
which colors show more than others in the pattern?
Thank you, I'm still getting my head around this time interference. So far I think i've come to understand more about how wavelengths might be constructed as standing waves carried within wave functions of past and future photons wave cancelling themselves at regular spatial/temporal intervals but after that it gets very discombobulating and makes about as much sense a submerging a photon in a singularity, so information like this is amazing.
Disclaimer, I'm not a physicist or scientist, but I do sound engineering. My question is, how is this different than Frequency Modulation? To me it would seem that the pump laser is modulating the frequency of the probe laser with the period of its pulses. Therefore its adding upper harmonic complexities. I'd imagine the band pattern would change based on the change in the period between the pump laser pulses. In Frequency Modulation you have an operator oscillator of a specific frequency and then a modulator oscillator that changes the frequency of the operator frequency by the period of the modulator. When you increase the frequency of the modulator you increase the intensity and number of upper harmonic bands. So is FM or harmonic theory an application quantum mechanics in the time domain?
We already use light for computers it’s quantum’s computing
Very very interesting.
If quantum entanglement is real then it may be possible to predict everything which will eventually happen. This means that two distant civilisations may want to send each other a message but the transmitter will not only know the answer before they have sent the message but the receiver will know the question before the transmitter has sent it, maybe by billions of years.
Quantum entanglement is an actual phenomen, but I fail to see how you can do what you described here with it.