New Experiment Could Settle 100 Years-Old Debate about Quantum Tunneling

Quantum tunneling is a fascinating process in which a particle goes through a barrier that it shouldn't be able to cross in seemingly no time breaking the speed of light limit or maybe not physicists have argued about just what goes on in Quantum tunneling for a century it seems like the kind of esoteric Quantum problem that'll never be answered but just last week the situation changed tunneling is one of these weird things that can happen in the Quantum world but that's totally at odds with our everyday experience if you hit your head against a wall it'll either go through or it won't if your head was a Quantum particle it would always have a chance of it going through tunneling can happen whenever you have a Quantum particle that faces a barrier which takes energy to overcome this could be for example because a particle is trapped by some kind of attractive Force you could imagine it being gravity but it could be anything the particle needs a certain amount of energy to escape that trap also it seems because if you take a Quantum particle it can get out of the Trap even if it doesn't have the necessary energy basically it takes the energy from nowhere escapes and then hands the energy back to nowhere so that energy conservation is fulfilled this sounds crazy but but Quantum tunneling is a real and measurable effect it's what scanning tunneling microscopes are based on and it place an important role for nuclear fusion where particles face such a barrier nuclei are all positively charged so if one approaches the other it'll be repelled by the electric force however the strong nuclear force is attractive it only becomes relevant at Short distances between the nuclei if you add these forces together that creates a potential barrier that nuclei can tunnel through this barrier is why fusion in our sun works the tunneling effect is not difficult to calculate you can see here what happens if you take a particle that's localized to a salt of lump initially and then let it hit an energy barrier this energy barrier which you see here isn't a real wall it's just some sort of obstacle that takes energy to overcome like the previously mentioned repulsive Force you can see that if the quantum particle hits the wall most of it is reflected but some of it goes through that's the tunneling but what's this shape that I've drawn here this isn't the actual particle it's the probability to find the particle because that's how quantum mechanics works so what the mathematics tells us is that any one particle has a certain probability of just going through the wall the weird thing is now this if you compare the speed of the particle that goes goes through the wall with one that never encounters the wall then it seems like the one which went through the wall will on average be faster because the average is where the bump of this distribution is if the particle was a Quantum of light then that means it must have been faster than light this isn't a joke there have actually been experiments where they measured this or at least it's what they think they measured you see the problem is that you can't really tell how long the particle took to travel because you don't know exactly where the particle came from maybe the particles that arrived sooner were just the ones that left earlier very confusing now comes this new paper with a very clever idea you'll love it they say look the key feature of quantum mechanics is that all particles are also waves this means among other things that they have an internal clock because waves w wave they change periodically like a clock now you can't actually measure this waving for one single particle but you can measure the difference between two particles this is how interferometers work so they say in the paper what they'll do is to create pairs of atoms that start out being synchronized in their waving so to speak let one run into the wall and the other one past it and then compare the results that should allow them to figure figure out what's actually going on does the particle kind of jump through the barrier with no time passing or do they both move at the same speed just that one takes the Forbidden path so to speak they haven't actually done the experiment yet the paper just explains how it work but they say it's feasible with current technology so hopefully someone will do this experiment in the near future and this might actually settle a 100 years old debate progress is truly Unstoppable who knows maybe we'll one day actually find out whether it's okay to put pineapple on pizza if you'd like to learn more about recent scientific developments I recommend you have a look at Nautilus magazine Nautilus is a Science magazine that keeps you up to date on the most relevant topics that are being discussed today they frequently have scientists writing for them who will tell you the inside stories I've written a few contributions for them myself most recently about John oppenheim's theory of postquantum gravity Nautilus comes with a digital an a print version and it's just a pleasure to read they really put a lot of effort into writing and the graphic design is top what I particularly like about Nautilus is that they cover all areas of science from astronomy to economics history Neuroscience to philosophy and physics if you use our custom link join nautilus.com Saina you get 15% off your membership subscription deson so go and check this out thanks for watching see you tomorrow

Channel: Sabine Hossenfelder

Views: 234,924

Keywords: science without the gobbledygoook, hossenfelder, science, science news sabine, science news, science humor, quantum tunneling, quantum physics, einstein, faster than light, quantum particles, physics, experiment, physics news, physics news today, science news today, science sabine, tunnel effect

Id: 2kTxX-0sYcM

Length: 6min 7sec (367 seconds)

Published: Tue Apr 30 2024