String theory vs Loop quantum gravity: Wild hunt for Quantum Gravity:
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- Опубликовано: 1 июн 2024
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The gauge bosons of the standard model of particle physics are responsible for 3 of the 4 known forces in the universe. A force is conferred is through the exchange of virtual bosons. So for example in electromagnetism, an exchange of virtual photons results in an exchange of momentum which results in two like charges repelling each other.
Gravity is missing from this picture because in General relativity, gravity is not a force, but is a curvature of space-time. The problem is that stars and planets are made of molecules, atoms and radiation. And the forces that hold the atoms together are due to discrete units of virtual particles. It is the exchange or swapping of these virtual bosons that holds or breaks up atoms and molecules.
Quantum mechanics conflicts with general relativity, because QM treats every thing as being discrete, and GR treats everything as being continuous. We need a theory that combines the two because we live in one reality, not two different realities.
This is why most physicists believe General relativity is incomplete. Why can’t quantum mechanics be the one that is incomplete?
Of the 4 fundamental forces, 3 have very robust quantum mechanical theories. Only gravity lacks a quantum description. Quantum mechanics also has almost all of classical physics within in its limits. Classical physics like general relativity, does not have quantum effects. We have learned is that Quantum physics is the fundamental language of reality.
One way to quantize gravity is to quantize space-time itself. This is what loop quantum gravity or LQG does. It shows that the fabric of space-time is not continuous, but is made up of discrete quanta, like the pixels on a TV screen. This is different than string theory, because in string theory, space is the background or the canvas, on which strings vibrate.
This means that distance has a minimum quantity of 10^-35 m. Area has a minimum value of 10^-70 m^2, and volume has a minimum value of 10^-105 m^3 - below which it cannot go. Time also has a minimum quantity of 10^-43 seconds, or about Planck time.
Space time is made up for finite loops with nodes connecting them. The nodes is where the quanta volumes of space reside. It has a volume that is a multiple of 10^-99 cm^3. The loops in between the nodes represent 2 dimensional areas. Large quantities of loops and nodes are called “spin networks.” Space is defined by the geometry of this spin network. Time is defined by the movement of this spin network. The spin network and quantum movements of time, is called a spin foam. Time ticks like a digital clock with each tick being 10^-43 secs.
When mass and energy are added to this spin foam, the shape of the volumes of the spin network is distorted, distorting space and time. This distortion is what we perceive as gravity.
LQG makes a testable prediction that photons of higher energy travel slightly slower than low-energy photons. But this has not been observed.
A second way to quantize gravity is to theorize a completely new mathematical framework of reality based on a new understanding of fundamental particles. This is string theory. It replaces the fundamental particles with one dimensional fiber-like strings.
Different vibrations of strings behave just like the elementary particles of the standard model. But the biggest problems is that these strings would need to vibrate not just in the 3 dimensions, but in at least 6 more spatial dimensions in order to mathematically account for the various particles.
It does't appear that additional large dimensions in our universe exist, so physicists think that these dimensions could be very small and hidden from our perceptions.
If you treat the universe as strings vibrating in 9 dimensions, a particular closed string vibration results in a graviton particle. So this would allow for the existence of a force-carrying particle for gravity just like the other 3 three forces.
#quantumgravity
#loopquantumgravity
#stringtheory
The promise of string theory is that all the fundamental constants, and properties of particles could come out of it. But 9 spatial dimensions is a problem. Another problem is that it requires the existence of super symmetry, where each particle has a shadow partner particle with different masses. No such supersymmetric particles have been found at the LHC. 
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Guys...let me know what you think of the sound on this video. We tried some new sounds and sound engineering on here. I would appreciate your honest feedback. Love it, like it, don't like it, hate it? Your constructive criticism is helpful, so we can continue to improve on future videos. Thank you.
Sounds just was great and Cristal clearly for me. In this video, the music was more clearly than the other videos. Especially in the middle of the video, music actually touched me (I wanted to say it, even before you asked. I thought it's just for me. But you said that you try to improve the sounds).
The explanation as well as sound design was perfect!!!
No comments on sounds... explanations were great
Thoroughly enjoy watching your videos and really appreciate your clear/concise explanations. I feel it has the right amount of detail so as to not overwhelm the non physics major yet enough of it for someone who would be interested in learning about the very universe we're living in.
Hi Arvin, I strongly disliked the music on this video, it made the explanations much more difficult to understand as I was focussing on the music rather than your voice. Please remove the background music completely, I can't understand why you would think it adds anything to the video as it's very distracting.
The content, script and animations of the video were excellent as always.
I just hope we get to see this get solved within our lifetimes. And of course, great video!
I hope so too!
Why don't do we try to solve beside to just hope someone else solve
@@rottenbanana5581 LOL
@@sepehrbagheri9968 why lol i said a deep msg 🤣🤣
@@rottenbanana5581 nice point well i cant do it
I leave this honor to u
That “When the next Einstein comes along” gave me shivers
Lmao, I typed in “Einstein gravitational theory” and found your video on it, was blown away and watched it multiple times and had utterly mind-blowing epiphanies at having it explained so clearly. By the end of the video you had me dying to know more about Quantum Gravity - but I suddenly remembered string theory, something I’d heard about years ago, and wanted to see if the two were connected.
Typed in “quantum gravity string theory,” clicked the first result, heard your voice, clicked subscribe.
Hell yeah man. This is gonna be awesome.
Figured it out! 😮 1st Page:
ruclips.net/video/5kARrZl66xI/видео.html
2nd Page:
ruclips.net/video/T3oor9i-Eh8/видео.html
3rd Page:
ruclips.net/video/wZsho-mibqE/видео.html
Aliens: They're getting close.
"they gonna be so pissed lol"
- Universe coders
Lol we can't explain 95% of the mass energy of the Universe. Hardly close at all!
You mean cats right?
Depends.
they grow so fast
Outstanding summary - the best I have seen so far
My congratulations !
Thank you. Glad you liked it!
I have been struggling with my health since middle school, I am unable to go to college right now and I appreciate the time put into these videos so I can still learn despite my health issues. THANK YOU
Hi Katelyn. Feel better. Prayers for you. You can keep learning even though you're not going to college.
Are you doing okay?
Am 65 control my health. By talking to cells . Your alive every cell in my body is too. Every atoms in the cell etc.
”A one dimensional string ...”
Ugh, uh, how can a string have just
“... vibrating in at least 9 dimensions”
Beer. I need beer!
because its a line not a plane. :P
but penrose puts it you need the extra dimensions so the strings can intersect, overlap and curl up, if they were in 1 dimension or less than 4 or 5 i forget off the top of my head, they would not be able to so the extra dimensions the strings exist in allow it.
C-shaped strings joining together create o-shaped strings. Now you can move from 3d space into multiverse. Space-time is not flat, but like bubble wrap upon bubble wrap.
Each beer adds another dimension. You need 9 beer to vibrate like a one dimensional string in 9 dimensions. With a partner, you enter into the realm of closed strings.
Beer. I need beer!
@@scottmiller4295 , thanks miles, obviously! I started on those beers too soon I think. I don’t know what I was thinking. Of course a line is one dimensional.
I have heard all those conversations in TBBT, from Sheldon Cooper.
I follow a lot of channels talking about physics, most of them having millions of followers, yet your videos speak to me and everytime I watch one of them, I learn something new that sticks in my head and becomes My Reality. Thank you Arvin !
I was so glad this showed up in my recommended now I feel smarter
When my YT algorithm fills with vlogs and comedy videos, I watch some Arthur Ashe and Lex Fridman to redirect my recommended vids
I went from -F to a whole F 🤔
Very clear and understandable! In a nutshell and without the math (though mathematical formulae show up, even the complete Lagrangian of the standard model!) the basics of the two theories, and their differences, are presented in a way that makes one understand the Nature of both. Quantum loop gravity even more than string theory. Thumbs up!
This video is the most overarching and in-depth science video I've ever seen. I constantly had to rewind to make sure I absorbed everything. Magnificent job! ⚛︎
I guess we all do the rewinding now and then... 😉
Hi arvin , started watching your videos few days back now i can't stop myself watching
Well, that sounds like a good thing! Welcome.
@@ArvinAsh still binge watching too haha thx
WOWEE, an Arvin video, Sabine video and Veritasium video all in the same hour! It must be my lucky day!
Me too i added the 3 to fav to watch them latenight 🤣🍿🥤
hey can you check one video from Science Clic English
They also explain dope, but highly underrated
This guy should get a full documentary series on the tv. I watch all his videos. He has a gift for teaching and his smile is infectious. I specifically enjoy how the information presented is not biased nor opinionated. Great content great channel. Thank you.
Wow. I loved this! Arvin you should get a prize for popularizing science!! The most complicated theories presented in such an approachable way. Truly impressive, you’re my hero man🙏🏼👍🏻👏🏼
Wow, thanks!
My cat prefers string theory.
Haha.
@Tunishq Von I bet to your dog you are God. Dogs are awesome 👌
@Tunishq Von Understandable; after all "god" is "dog" spelled backwards!
The ancient Egyptians thought cats could see in all 9 dimensions, which is where the theory that cats have 9 lives came from
@@pilar4726 That's a cool story. I love the ancient Egyptians.
The fact that I'm 11 and I understand this almost perfectly goes to show how good your videos are.
Great that you're watching a video like this at your age! Stay curious buddy!
You are smart tho 👏
Poor dude you will realise you understand nothing in time.
Little does he know both of these theory's are probably wrong lol
@@cellerism I don't think he is saying he perfectly understands the frontier of modern physics ^^
He thinks he perfectly understands the simplified road map for interested everyday people this video tried to draw.
And thats totally fair.
The background music could be lowered just slightly at times
Mind blowing simple explanation. The same kind feel I got in each and every lecture of Dr. V. Balakrishnan sir( IITM). Great, go ahead
I must be made of quantum strings since my wife says I'm one dimensional
You're still ok...my wife says my 3-dimensional penis is too short, whether she measures it or not.
No you have some hidden dimensions too...ie 10 hidden
The penis may have 3 dimensions but the effectiveness is greatly diminished if 2 of them are wrapped up within themselves 😁
Hilarious...!
@@edzanjero353 You are lucky: I need to roll it so around my waist.
Loved it! Each video is better than the last. Thank you for taking the complex concepts of string theory and condensing them into a simple explanation and showing how the theory aligns with the standard model. Your work is incredibly helpful and much appreciated. Keep it up!
RUclips says this is the last video I'll ever see without removing ad block. I guess this is good bye. You've consistently done a great job explaining the meat of concepts without dancing around them or injecting inaccuracy that just confuses people like some other science communicators. Thank you for that.
Thank you so much Arvin Ash, this is an amazing explanation video. You explain it in such a simple way and use pictures to help me visualise it. I tried PBS space time but they are too complex and they dont explain it simply enough but you do, thank you.
I think advanced research on black holes can provide us with some solid evidences of either of the two theories. The amount of gravitational fluctuations around primordial black holes is massive and these fluctuations can unfold major secrets. The gravitational fluctuations can be detected as disturbances in the speed of light which can unveil something about Loop Quantum Gravity. On the other hand the space around the singularity can provide us something interesting about string theory.
Let's hope we unravel this mystery soon.
Well that's an optimistic take, if I ever heard one :D
The richness of details along with the amazing clarity with which you present this information to us in your videos is, I think, unparalleled on RUclips.
Keep up the good work, Arvin!
Thank you. I appreciate your kind words!
I find Science Asylum pretty good as well
I'm a researcher (in particle physics) and I think your video is extremely well done. I'm not sure though how much a non-expert in physics would understand ;).
One comment about the part of the video where you argue which one between QM and GR is incomplete.
This part is a bit misleading, since GR is a theory while QM is a broader concept which comprehend several theories (classical QM, SM of particles,...). I understand that this is not easy to explain in 15 min, but I would simply say that both approaches are incomplete and they need to be unified.
Keep doing your amazing videos!
Best wishes,
NG
Mr Ash I love this video it is exactly what i was thinking. Thank you for answering my question that i asked on one of you videos recently in this video.
Thank you again!
This was an outstanding video. You explained why it's difficult to reconcile quantum theory with general relativity, and you explained loop quantum gravity and string theory, and how they attempt to solve the problem, and you did it all in a way that was easy to understand. Impressive.
You're great at explaining! Makes me think that I have a chance at one day actually understanding these things fully. Love the work.
As a subscriber to numerous physics/physical science/cosmology/whatever channels, I find yours to be one of the most lucid, understandable, and succinct yet comprehensive channels on RubeTube.
Dear Arvin.
Thank you for your amazing way of explaining so complex things in a understandable way. Maybe the background sound could be a little lower, but your visualization of complexity is phenomenal.
Sir,the sound effect in this viedeo is fasinating and have different dimentions.thanks for the lovely efforts ,thanks to the sound engineer also.it is fantatastic to hear nature ,secretes with your clear explanation along with the lovely misitical hevenly musical sound.
Very cool explanation of loop quantum gravity, I've listened to a lot of videos on that topic, but this is the first time I heard it explained so straightforward and understandable!
With that in mind, could you make a video on just LQG? Would love to hear more details about it from you
Thank you for making RUclips a better place!
A compliment often repeated, yet your channel fully deserves it!
Wow. Fantastic video. Can't wait to watch more. This was so helpful. Thank you.
This is pure gold. Very logical and nicely presented content.
That animation of bosons getting exchanged analogous to the people on the boats was awesome. A very nice perspective to understand attraction and repulsion, caused by exchange of bosons.
Similarly for Loop Quantum Gravity the animation was excellent. These things create a perspective which is hard to get just by reading. With this, when the maths behind it is studied will help bolster the understanding for young people and enthusiasts.
A great service to Science
Yeah..
What a wonderful channel 🥰. Thanx for these quality content 🙏🏻
Excellent summary of both theories! Thank you Arvin!
At uni, I came up with the postulate that the expansion is not universal but happens in discreet areas. Like bubbles of space expanding.
Thay would mean they collide and the colliding parts would have different relative speeds.
If the relative speeds reach certain %ages of the speed of light, the place where the "collision" occurs will be subject to time dilation and space contraction. I.e. tiny, "permanent" areas of space will manifest. We interact with these as "particles".
So, a particle is actually just a part of space that exists on a different level to the rest of space.
This explains why things appear "quantised".
If you look at deep-seated images, you can see galaxies form at the edges of voids of space.
Just an idea. I was never good enough at the math to calculate spherical and vortex phenomena in actual equations.
An *Even-handed* Summery!
This is a rare 🐦. Well Done!
I haven't even started watching this video, ad's playing, but I am pretty sure, this is gonna go above my head
I've watched all the great physicists try to explain why quantum theory n GR can't b combined , hours n hours n in just the first 5 minutes I now get it ! Professor Jim Al. is my favorite also but your right up there Arvin keep explaining n I'll keep watching ! Thanks
Thanks. Be sure to check this out as well on the subject of quantum gravity, where I get more into it: ruclips.net/video/S3Wtat5QNUA/видео.html
Will do
Very well explained ! All told, the video was excellent (sound was fine). Thankyou !
Y'all are fantastic at this. Glad I found this channel. Love your work, Arvin.
I wish I could see a collaboration between you and Matt O'Dowd from PBS Spacetime, somehow. Perhaps a pass-off video where y'all split the video halfway, each discussing a phenomenon/problem from a different perspective. (Could even be filmed remotely.)
Hello sir. I am 12 years old and I am learning quantum , thermodynamics ,electromagnetism,string theory and the best lesson is quantum gravity. And your video was really helpful and I enjoy it✅✔✅✔🚀.
You born astrophysicist.Not only ,you authored at age 12 calculus book and atrophysics book about quantum gravity and every thing related to physics! Wish you to reach your dream to be Astrophysicist
Same here. Even i am 15 yrs old and learning these concepts. If we could team up and work together, it will be more easier for us. Think about it and tell me ok😄.
@En Nodi yea but not tat complex like tensors, vector calculus.
@En Nodi yes
@En Nodi only the basics
I have read but mostly watched so many videos about these theories and in general i understand them as a concert, yet struggle to keep up in some way. Never the less i keep watching 😁. Thank you for the educational video
One of the best introductions to why our reality is mind blowing. Can't squeeze all that stuff into a short video but enough to touch on the main points. Relativity, quantum physics and the far out theories trying to reconcile them. I like the explanation of string theory.
@Arvin Ash Probably one of the best videos in physics on youtube. I have no background in physics but your videos and the animation make complex theories so simple and easy to understand. Kudos on another great video. Can't wait for the next one. Btw can you make a video on the holographic principle and how it conservation of information on black hole, and if it is related in any way to the quantum gravity or string theory? Thanks
Thanks for your kind words. I made a video a while back on holographic principle. If you search on youtube for "holographic principle arvin ash" you will see it.
You have explained in best way
Brief and excellent explaination Sir
Thank you💕
you are the only guy on youtube who actually explains stuff in the good way without losing time talking about pointless informations
Excellent simple but deep discussion to the conflict between both theories. Thank you for your great efforts.
I was just thinking: I wish Arvin had a video explaining loop quantum gravity. And here it is, you are a wizard Arvin.
I see that string theory comes with a lot of strings attached
wow, where did you pull that joke from.
@@jjsamuelgunn1136 Don't pull legs
@@jjsamuelgunn1136 from my hat
@@jjsamuelgunn1136 ruclips.net/video/yI7kFyzg-BM/видео.html
@@SamvadSoul ruclips.net/video/yI7kFyzg-BM/видео.html
Amazing stuff ❤❤. I will watch all your videos soon
This has been the absolute best explanation so far
I've just discovered this guy. My gosh where have you been all this time!
Very nice video installment, very easy to follow and understand. Thanks 👍
Thank you for all the fantastic videos, you provide the best explanations
I realized why I like your contents. The introduction is everything, it reminds me of scientific journal articles' abstract. Instead of reading it, listening is more interesting and easier to understand. Thankyou so much, Sir 🤓
One of the best science educators of our time. I hope for big things for you.
Been watching physics videos for many years, that was some of the best explanations I've ever heard and I learned stuff. Thank you
Outstanding Alvin. Spectacular.
When you think about it string theory is so messy compared to lqg.
But keep in mind, ST would also explain more things.
I agree seems very out there, but reality is weird
@@ArvinAsh Yes definately, when you come up with lots of extra dimensions to prove your theory there's lot more explaining to do ;)
@@ArvinAsh Would it be too late to suggest that the reason nine dimensions are needed in ST may be due to the three fundamental QM forces each having their own independent 3-space manifold to operate within, all intersecting at the quark?
@@markiv2942 The bigger problem is IMO no super symmetry partner particles have been found yet, which is very odd.
A more balanced approach to explain the theory of everything than other channels. No pet theory, just facts.
Amazing summary. Keep up the good work!
arvin always makes these topics so clear and understandable for us plebes. and fun too. as soon as he says sonething and i have a question he covers it.
This premier is such a great idea. Amazing channel, keep going 🤗
Producing videos like this is a good way of inspiring the next Einstein IMHO :) Thank you !
This is the best science channel on the Internet. Very pedagogical and interesting.
Fantastic vid Al. Thank you very much.
Superb Video Arvin, Do you think this implies simulation because of such rule set kind of like how we define while programming, configuration of fundamental constants, plank's length, time as shortest for this universe!
I don't think so. Our universe simply has some mathematical rules that it abides by. Proof of simulation would have to come in some other form in my opinion.
The universe doesn't run on maths, maths is the decrypted form of the universe.
Or perhaps we are just all a simulation indeed, in that case, hey infinitely dimensional alien, nice work and all, but could you remove the "existential dread of being at your 20's and still having accomplished nothing" feature?
Never disappointed by Arvin Ash! Presenting material in a way one can understand. You didn’t lose me once. And your passion always inspires me to imagine the possibilities while you’re talking. Never boring always educational. Thanks Arvin
Awesome! Thank you!
Superbly well explained! All the right questions. I successfully derived the centripetal a = v^2/r from no more than the notions of Planck length & time from quantum loop theory and energy density that General Relativity's equation includes. Knowing next to nothing about any of these, I overly simplified.
Thank you Arvin Ash. You are a great explainer!
Always the best, simple but rigorus.
I feel like I need two more cups of coffee and a PhD to fully understand this video. And that’s considering that these are mere representations of much much much more complex mechanics.
You keep impressing me with being able to give laymen explantion in 15 min of extremely complex subjects.
Thanks for a great upload
The video content was really great.. make more on this topic... thanks man❤️
"Complexity is the result of Simplicity not wanting to be alone." - Wald Wassermann, Physicist
9:29 "Loop quantum gravity (LQG) predicts that the speed of light has a small dependence on energy."
Wait... what? Whoa! Now THAT'S what's called a RISKY prediction!
Explain your statement.
Great to see the channel grow and the audio is better I'd say.
This was easily the most fascinating and well explained video I've ever seen. Incredible. Smashed that subscribe button with the force of the sun
Thank you! I finally understand how general relativity and quantum mevhanics do not work together. 🙏🏼🙏🏼🙏🏼
Arvin Ash has had an exponentially greater success at increasing my scientific literacy than Neil DeGrase Tyson could even hope for.
It is not necessary to demean others while complimenting someone.Neil is someone who make science intresting for general people and only after someone takes intrest in science someone like arvish can help to understand the scientific concept in depth.
Yo that was kinda low key racist my guy
@@lilricky5050 if the racism was the first thing that came to your mind while reading that comment, it means you are racist
Excellent video. It must take a lot of work to do it. I understand this stuff better. At least I think so. Thank you.
Love your channel so much!!
The next Einstein would be lost in scrolling his phone
Indeed!
🤦♂️🤦♂️
Who said? From what i gather he would be unlikely to use much social media at all. Too much time thinking bigger thoughts than 'wonder how people feel about lamb tonight ....' ;p
@Tunishq Von 🤣🤣🤣 😭😭😭😭😭
Bro...I m next😂
The next Einstein will never come but the next ' Someone' will surely come.
Hey Arvin, the closing bgm was great.
Great video !!! Sound is good !!
♥️🧡💛💚💙💜🌟
I will try my best to help humanity by making a theory of everything 🤞in future .
Really good video! I'm convinced even more that Einstein's spacetime is wrong and a new theory of spacetime for quantum mechanics is needed...
You give a really illuminating exposition of the attractive mechanism for photon exchange between unlike charges. For that alone I'm grateful, as I had understood the mathematical reasoning decades ago but never got a visual image of the process. But the explanation of the difference between loop-quantum and string theories is wonderful. I am a physicist of a much more mundane sort. Even though I use quantum theory daily, this field is one where I very much lack the tools. I'm planning slowly to teach myself, simply to delight in the elegance (and appreciate the gaps).
Wow! Creation is amazing, great video Mr Ash!
Gravity is a consequence, not something that has objective existence.
yes
Gravity is - The difference between slower and faster time flow in the time space.
and you both are from VSauce
@@renanmaas3502 actually this is my idea ... based on my knowledge about light , time and gravity.
If Newton Tesla Einstein Hawking were alive, it was nothing to sovle the theory of each and everything
Maybe you are right
Team Leader would be Newton
Hahaha!! 👍👍👍
Why didn’t you add max pluck and Heisenberg?
@@nasreenafroze1326 lol
@@scienceq7475 then Einstein would quit
Strings as points in time could vibrate in extra dimensions bottom to top, quantum dimensions of planck time, and regular spatial dimensions as part of graviton particle when reach planck space
Extraordinary content. Thanks a lot Arvin Ash👍
Long live LQG✌
Does higgs mass also contribute to gravity???
Higgs boson has mass, if that's what you are asking.
@@ArvinAsh I just wanted to ask that the mass which is due to higgs field, does it contribute to gravity? Or is it only mass which is formed from energy can cause gravity?
@@haneechaitanya3832 See my video on electroweak theory which might clarify the mechanism. The mass gained through interaction with the Higgs field also affects curvature of space time, and so will have gravity.
@@ArvinAsh sure sir, thank you