Doing The Impossible
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- Опубліковано 16 вер 2024
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Physicists Amir Safavi-Naeini and Oskar Painter describe how they were able to measure quantum motions of 1 femtometer (0.000000000000001 meters) in a micro-scale object.
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Featuring: Amir Safavi-Naeini and Oskar Painter copilot.caltech...
Produced in Partnership with the Institute for Quantum Information and Matter (iqim.caltech.edu) at Caltech with funding provided by the National Science Foundation.
Transcription: Noel Dilworth
Thanks to: Spiros Michalakis, John Preskill and Bert Painter
#FQXiVideoContest2014
And that's where it really get's interesting. ... .... end of video. Goddamit
0:12 that is possible the most fitting graphic ever applied. _'Oh, okay. Oh well.'_
Love that you worked in the Dude there. It really brings the whole room together.
I like how these two mega brains didn't play by the rule and just ignored existing boundries. Kudos.
I love the universe... It's not only amazing at a huge scale, but almost just as amazing at the very, very small scale!
Thanks for posting!
This was fantastic, i have some idea of what quantum mechanics is now. Beautifully done and I'm hoping teachers can show this in class rooms
This is absolutely fascinating. I can't wait to see more on this.
Yes! This is possible if the entropy decreases with increasing energy, a property that can be found in systems described by Hamiltonians that are bound from above, like spin Hamiltonians or like particles in a bloch band with attractive interactions. If you take -1/T as the new measure it smoothly increases from -infinity to + infinity in such systems with increasing energy.
So beautifully described. Thanks for that!
Is there any continuation, next part of this video? Because at the end they were talking about describing other objects with quantum mechanical wave function and "that it's really interesting", and I'd really like to hear about it...
I had not thought of that. That's a really good explanation. Thank you.
Yes, the temperature of the sample will go up, when you bounce the laser off. They probably used a pulsed laser -- bounce a very short burst of laser light, make measurement, then wait a little so the sample can cool off again, then try again (and again, and again, to make sure the measurement is not just noise).
Such a good video, so clearly explained
That has been done recently in Bloch's group in Munich. But be aware of the fact that negative temperatures are actually hotter than positive ones! (-1/T would be a better neasure for temperature)
I love when someone says: "It can't be done!!!"
Then some young guy arrives and does it.
It feels good!
Thank you. That's an incredibly easy interpretation that even a non-physicist can get the general idea from the paper. I'm very excited to learn more about quantum mechanics, but I'm afraid I would have to be learning those on my own in the future. I kind of half wished I chose physics instead of chemistry xD
OMG how do you get rid of all the vibrations of vehicles moving around, peoples walking by, breathing etc?
This is completely amazing!
I just love the "The Big Lebowski" reference at the end of the video =o)
Nice, gives me chills
cool, keep thinking about these things
this was so good, more please
I always have wondered that. Thanks for explanation
I skimed the paper and the model used there is the lorentz oscillator model (applied to quantummechanics). Basically you assume that the atoms of the molecule are connected by springs among them and light forces them to bounce.
You are right, it's impossible to go lower than zero in absolute temperature.
They just rounded it, because it's very very close to zero.
The object is vibrating due to the Heisenber uncertainty, but the vibration is so minute at 0K that it dosen't have the energy (it has on energy at all actually) to "push" the photons bouncing off it even if the vibration is in the direction the photon bounces off in, so each photon hitting the object "pushes" the object a tiny amount away from the source of the light as it bounces off, loosing a tiny amount of energy in the interaction thus the light reflecting of the object gets red-shifted.
Well designed- بسیار عالی و منون از این سری برنامها
awesome video, thanks guys!
Super freaking awesome!!!
Well, the reflected light is more blue than the incident one if the frequency is higher, hence the term blue shift. It might not look blue, but it is more blue than before. :)
Great explanation! I love this channel! How can this be employed in the real world? What does it or what can it mean to me?
Nope, but you can make them "ground state" that's just a spec of enery before 0K , and that energy comes from the Heisenberg uncertanty principle (it's also called ZPE : zero-point-energy)
I dunno anything but just wondering... I'm thinkin ur not at absolute 0K just really close to it. Also, how come there's no energy transferred from the beam of light?
Blue shift is the light wave you get when something is moving towards you in this case photons. Red Shift is the opposite and is the light wave that is moving away from you. When they hit the 0K temperature on the mirror it reaches its ground state which is the minimal state of which an object can move which is 1 femtometer. At this point it is at minimal energy as well. Blue shift always produces more energy then red shift because the dopler effect pushes the mirror and the mirror push back
Awesome experiment.
THAT"S SO COOL!!!!!
The particles in all objects are always vibrating. If you measure how much they vibrate, you are actually measuring their TEMPERATURE, because that's what temperature really is. The particles in a glowing red hot objects are moving much faster than the particles in a cold object.
At 0 degrees Kelvin, the particles stand "allmost" 100% still, except from some small vibrations that I don't really understand where come from (I'm not a physicist)
Really great video! I learned a lot!
Kick logic to the curb and do the impossible! :D
Mad props to these guys. The day we get the quantum world and the macroscopic world to play nice together is the day I get to ride a teleporter to work.
I've been waiting for quantum computers for so long!
As I understand it, the redshift indicates that the photon htiting the object can lose energy (i.e. giving energy to the mirror object), while the lack of blueshift indicates that it is impossible for the photon to gain energy (i.e. taking any more energy away from the already 0 energy mirror object).
I just learned more in 5 minutes than I did throughout the entirety of my QM undergrad course
Mind Blown!
Just stumbled across this awesome video. Subbed!
Awesome!
Don't worry about it. It's good that you can admit that! You can check out MinutePhysics for some more introductory material, if you're interested
I have a thought: at 0 K the photons from laser will also occupy the lowest energy state (Bose Einstein condensate) and when it strikes the mirror at 0 K, the photons cannot transfer their energy to the mirror and emit the red shifted radiation as they are at their lowest possible quantum level, how can a red shifted radiation then emit from the mirror?
Since the mirror is at a minimal energy minimal movement state it does not push back so the blue shift dissipates leaving the red shift (the initial push from the photons) to be detected
It's an allowable approximation. They never stipulate that they need absolute zero, just that the doppler shifts will appear once you get to zero-point energy. That being the energy you have at the lowest possibly temperature allowed by Heisenberg's uncertainty, or the ground state. The colder it is, the less noise. The less noise, the easier it is to see the red/blue difference. This happens at 1K, 200K, 400000K; doesn't matter. It's just easiest to see at that low temperature.
I may be wrong, but it seems to me that given the material is in its ground state, any collisions with photons can only result in photons losing energy as there is no energy to gain, which would cause the blue-shift. As far as the vibration goes, the only explanation I have heard of that is that the atoms would be 'vibrating in fixed positions', which, while I don't really understand it well, could explain why the atoms don't simply 'knock' the photons away causing blue-shift.
the wave you speak of is the wave in space time when the photon travels in space and leave a wave. that why you can use wave form to predict behavior. photon has very little mass but when it move at the speed of light it has a lot of mass. that mass traveling in space generates the wave form.
My mind just exploded. Or, imploded. Can't say which. ;)
It is my understanding that Heisenberg's uncertainty has little to do with the energy of light bouncing off a particle when you try to measure it's state. The uncertainty arises from the probability wave function. it is not a limitation of the instrument you use to measure the state of the particle. If the probability wave function of the position is sharp, the momentum wave is broader and of the momentum wave is sharper, the position wave is broader.
You most definitely know a lot more than me. I'm not a physics major. I just wanted to let you know that the video seemed a little misleading. if I'm wrong please do let me know with in reply to this comment. That being said, I'm a huge fan of your comics.
Thank you.
awesome!
The light doesn't bounce off. It's all right to imagine them as particles but we need to remember that they don't act the same as two tennis balls. The light is absorbed into the atom (giving it energy), and is then later emitted in a random direction (reducing energy). But in-between these events it has lost energy to the low temperatures. So when it finally releases the photon it can only have less energy.
I do not understand why this is a prove of the uncertaincy relation. Why doesn't the classical explanation work here:
- the matter is at (as good as) 0 K
- a photon hits the matter with the energy E = h*f
- the photon transfers a part of its energy to the matter -> red shift (E lower --> f lower)
- because the matter has to be constantly cooled down the next arriving photon will not get blue shifted
(0:45) For those who are unaware the Heisenberg uncertainty relation should not be confused with difficulties in measurement.
I wish the featured physicists had also explicitly stated which interpretation of QM they accept. They seem to be concluding that the Copenhagen interpretation is incorrect.
Temperature is the average 'jiggeliness' (translation, rotation, vibration ect.) of molecules, and as such is something that only makes sense in a macroscopic world.
Any temperature is best understood as x m/s average speed of the molecules, some fly faster and some fly slower, if you invert the boltzmann distribution of the the molecules then you (by definition) have negative temperature, this is of course very unstable and the atoms will quickly collaps into a more stable state.
Negative temperature is a quite different concept than absolute temperature :P Although after taking two graduate courses in Thermodynamics & Statistical Physics, I have lost any understanding of the concept of Temperature, and it gets bizarre the more you learn.
it is still vibrating. just that it can't give energy to the light when moving forward and cause the blues shift.
For all of you saying that the frequency changed when Energy was absorbed by the object: if energy were to be absorbed, it would be the amplitude that suffered. You would not see lower-frequency light, you would simply see less light.
Could be absorbed, but could also be released as reflected light that is "random" in the sense that it doesn't have a doppler shift.
If the oscillator they are talking about is the only degree of freedom you can go to the point where there is no lower energy state possible as they explained. When you talk about more complicated system, a gas of some sort you have many degrees of freedom where it is very hard to go to the real ground state and then the tell you about nano Kelvins. Meaning of temperature kind of looses it's every day meaning at extremes.
you get to the negative temperature by going through the upper end of the scale, not the lower one
it is not the movement, It is all about energy absorption. The object absorb some energy, and lower the reflection frequency.
I think that was just an approximation. It is statistically impossible to have a body with only a ground microstate available, but it is possible to achieve a system which has a large quantity of ground microstates at such low temperatures, though.
That's not restricted to quantum stuff though.
Basically, it turns out that 1/T is a more natural quantity than T. It's called the thermodynamic beta.
Negative T or 1/T corresponds to the temperature becoming "infinite and then wrapping around". In other words, negative temperature is hotter than any positive temperature, not colder.
no it just means it doesn't have enough energy to return the blue shifted light and is instead absorbed by the object. So log as they put more energy into cooling the object than it is absorbing it will stay at the temp they want it to.
It is because of the definition of Temperature in terms of change in entropy. The reasons are mathematical.
Since the energy levels of the oscillator are quantized with an energy separation haber omega, temperatures k_bT well below hbar omega will be enough.
well done experiment ;)
It terms of energy, that makes sense, but not in terms of physical movement. If a red shift is detected, that means the doppler effect is in play and there is movement away from the source, but not towards it (from lack of blue shift)? So was I correct in my hypothesis of the mirror being (ever-so slightly) pushed back by the light source? That was my initial question.
Can u guys explain why only red shift occurs, when the mirror at 0 K, is hit by a photon? if you can provide some source explaining that, would be great. thnx.
Very interesting but I do wonder about one thing. Since a red shift implies a lowering of the frequency (and hence energy) of the reflected photons, where has that energy gone? Isn't it absorbed by what they're bouncing the photons off of? And if that's the case then wouldn't you still get some blue shifting which is reabsorbing the energy imparted by the red shifting?
I think they know that :) but they also need it to describe that, so they used pretty simple analogy that fit :)
Why couldn't they have cartoons like this when i was a kid.
Yes.. you are right.. but I think, there happens something whole different.
Reflected Light is nothing different than stimulate particles per photon to a different state, and then the particle jumps back to its original stat and sends the photon right back.
if there is no energy to GIVE, the photons cant possibly be more energetic-> blue-shifted, there is just the red-shifted amount of energy taken from the photon..
that's my interpretation.. you warm up the material..
Have you published any papers on this? If yes, where can I find it?
what software did you use to create this video? its impressive!
Mechanical objects can be described by quantum mechanic wave functions? MADNESS!
That entire Doppler effect argument seems a little fishy to me (but I might be biased as a chemist and I haven't read the papers yet). To me this looks more like the Raman effect: scatter light from a molecule and you will see a blue shift if one (or more) vibrational quantum of energy was lost and a red shift if the molecule picked some energy to get to a more excited vibrational state. Ground state: No anti-Stokes (blue-shifted) emission.
If the electron is still in motion around the nucleus, how can there be a zero temperature? If you prefer to think of the electron as a wave, then, where have you delineated a definition as to the threshold of where the atom's "surface" actually is?
Why is the blue frequency disappearing faster. Look at this: When it's moving towards the light source, it reflects light without decreasing its wavelength. When it's moving away from the light source, it reflects light increasing its wavelenght.
So it reflects the light with the same or lower energy and never higher. We are receiving less energy than we sent. What happens to the missing energy? It can't disappear.
Oktek94 It goes into 4th dimension?
According to a phase singularity, it may be appearing and disappearing between cycles.
And relativity effects does can not only be observed at great masses and near light velocities.
I wonder why they call it negative temperature though. Since any negative temperature is hotter than any positive temp(in the sense that energy will always flow from the neg temp side to the pos temp. side).
Needs a better name I think.
No, the illustrative example isn't physically correct. In fact the metal absorbs the light initially (by altering the vibrational energy of the molecule) and then emits another lightparticle. The maximum energy of the new lightparticle is the difference between the current energy of the excited molecule and its ground state energy.
If you don't follow me, look up "raman scattering". ;)
I think they would measure shift relative to the reflected wavelength from a stationary atom, so classically it would be 0.
If it was moved away, then the normal force of whatever the mirror's on would push it back up, causing a small jitter, right?
Could quantum physics represent the physics of time?
In this theory the quantum wave particle function Ψ or probability function represents the forward passage of time itself with the future coming into existence photon by photon. Quantum uncertainty ∆×∆p×≥h/4π that is formed by the w-function is the same uncertainty we have with any future event within our own ref-frame. Wave-particle duality is forming a blank canvas that we can interact with turning the possible into the actual!
Very interesting. Energy is a shapeshifting particle-wave. So, energy can't be destroyed, is transformed. Then, Making it to go 0 Kelving will be like canceling the energy it have, making Quantum uncertainty cancelled or a byproduct of stopping the particle in time by cooling it? If at these temps, you have still have reading, then where from is energy comes? Plank energy or neutrinos passing by? Any thoughts?
I have my head thinking turbo crazy now. ;-)
TALK ABOUT IT NOW!! (superposition, quantum tunneling, etc.)
No! he pouts. I want to talk about the bizarre and really interesting part right now~~ haha do elaborate!! thanks!
same concern here..
If you're bouncing light off it from multiple directions, it is very unlikely that it just so happens to be moving away from you every single time.
When light reflects off the object, it loses frequency, this happens whether the object is vibrating or not. There's just no vibration to push the waves into blue shifted light. That's what i believe the answer to be, but i'm no quantum physicist.
Epistemic, the position of something is assumed to exist, but knowing it is seemingly impossible.
They didn't really explain how the red shift exists when the blue shift disappears (that I picked up on). Could someone explain this? Is it from actually pushing the whole object or the local atoms back with the laser?
Forgive me if this is a basic question, why do we see blue shift and not violet shift?
Big Lebowski reference there at the end? :D
but if there was any thermal energy would the blue light reflecting back not have dropped of at the same speed as the red light and not faster?