These are awesome. I’ve listened to probably over a 100 vids on physics, but these go a level deeper, with the actual physicists debating and explaining their ideas in a highly technical yet still understandable frame. And there’s host interjecting at appropriate moments to summarize and clarify a point when it gets too condensed. Kudos!

@PhilHalper1

4 ай бұрын

Thanks very much, we will have a new debate in early Jan.. Watch this space I'm very excited about it.

If patience was a field, Gross would be a particle

@g.o.a.t4674

5 күн бұрын

He was very tolorent.its carlo who ruined

1) First I want thank skydevil for publishing this video. 2) I wish that David would let Carlo speak from time to time. I want hear what he has to say. David seems to be a bad listener, a big shame. If he did not want to dialogue and only give a conference, just organize a conference for David. This is very disappointing. David speaks for Carlo. He does let not Carlo speak. That is certainly bad manners. David does not let Carlo finish. It looks like a political show, "vote for me" kind of game, and very little interest on what Carlo has to say.

Regarding the Higgs particle in Loop Quantum Gravity (at around 1:05:00) I've done two articles regarding that (and also my thesis). The short answer is that not only you can define spontaneous symmetry breaking in loop quantum gravity, but you can arrive to a theory which does not require a Higgs particle at all to describe massive vector fields. Since youtube dows not like links in the comments I will provide the titles of both my articles and my thesis. If you google them you will probably end up with very few results. The Proca-field in Loop Quantum Gravity Spontaneous symmetry breaking in Loop Quantum Gravity Massive vector fields in loop quantum gravity

@PhilHalper1

2 жыл бұрын

thanks for this, much appreciated.

I was somewhat disappointed that David Gross did not allow Carlo to fully explain his full points before diving in. I think this should have been done by Phil, allowing each person to present and counter separately and then finally debate. Carlo was impeccably polite and complimentary as ever.

@PhilHalper1

2 жыл бұрын

i think I should have done a better job in resining David in, but as our poll had Carlo as the winner Im not sure it did his side too much harm.

@physicsprof.9639

11 ай бұрын

When gross stops for a minute he site there with a horrible condescending smirk . What an a xxxole.

It's humbling to see that a discussion between two of my favourite minds in physics can resemble my Dad and I talking about politics at Christmas.

Gross is defensive of string theory because it forms part of his ego. It's hard to be objective when your identity is so highly entangled with a given framework.

@Achrononmaster

2 жыл бұрын

Honestly though, if we had done what Gross did we would all be defending string/M-theory even more vociferously. Human nature, you defend your tribe, even when they are dicks.

@SEJay-gj2cv

2 жыл бұрын

@@Achrononmaster Fair enough, but let's follow through with your analogy. Human nature, you get tired of having to defend a bunch of dicks and go find a new tribe or just embrace it and become a dick. It's sad but another human nature seems to be that it gets harder to consider new ideas or question one's own beliefs as we age. Science advances one funeral at a time sadly. Adapt or GTFO

I never knew there is this much tension between loops and strings, discussion was hard to moderate seemingly. My sympathy goes to Rovelli, who at least tries to keep discussion open, whence Gross is more on the established convention and declarative side of authorian science philosophy. That feels so last century in the current potentiality of debates we could have. But, I enjoyd and decided to listen a few more times and share to my friends interested in topics.

@PhilHalper1

2 жыл бұрын

glad you liked it and thanks so much for sharing

@Achrononmaster

2 жыл бұрын

To be fair you should not paint Gross as so "authoritarian". The orthodoxy will alwyas defend itself, if not then it's not the orthodoxy. I am not a big M-theory fan, but Rovelli, Smolin, Loll and the others have not given us much else, you realize all the "discrete space" approaches are only theories of gravity right? They tell us nothing about the Standard Model. M-theory at least has oodles of gauge fields in it's spectrum, the problem really being too much crap on top. To my mind, the value of these discussions is in keeping young budding theoreticians and experimentalists eyes & minds open. If supersymmetry can be experimentally ruled out then it'd be one of the most amazing discoveries in the modern era, bigger than the Higgs. One of the greatest negative discoveries ever, akin to Michelson & Morley finding no aether. So the experimentalists have to get involved here, and figure out how to get beyond the LHC.

@mesokosmos2212

2 жыл бұрын

@@Achrononmaster This is not the first interview I listened about both guys. Former gave very similar impression. Orthodoxy there is certainly, and school books are always outdated what comes to latest achievements. This also makes the argumentation difficult in these issues. Gross commented on something that he was not involved for a decade and where Rovelli is doing his active research. How would you debate constructively in such situation? I do think that Rovelli and Smolin have given much for the community. Their work is important by other means than Nobel, which sometimes becomes obstacle in the progress rather than a sign of the constant development.

This was amazing. Phil was really good at managing the time. I loved David’s expressions he got so frustrated at times. Carlo was so polite.

@PhilHalper1

Жыл бұрын

thanks

Good job Phil. I feel we need more such civilized debates of polarized issues in society. These guys definitely need to talk, and LISTEN to each other, more often. My current appreciation of both sides is that they are elegant storytelling. It will be interesting to see how it all unfolds in the future…

@PhilHalper1

2 жыл бұрын

thanks so much for your comment.

If Prof Gross could let Prof Rovelli finish a whole sentence that would be nice

@MrSamialbeik

9 ай бұрын

I dont like people who are sooooo sensitive when people are interrupting each other … thats how a discussion goes. Also the entire time Carlos explained what his review of string theory was about … David didnt interrupt at all. So dont be so sensitive its redicules

@mideoryan3375

9 ай бұрын

@@MrSamialbeikgenerally that’s how discussions are but this is a public debate, there must be decorum so that the audience too can follow and fully understand each person’s position. Also there’s a difference between debate and argument- debate has rules. Gross generally didn’t follow those rules and kept interrupting (mostly)

@nysewerrat6577

8 ай бұрын

@@MrSamialbeik Not really. David Gross looked like he had to go to the bathroom the whole time Carlo was talking lol. The guy has no patience at all

@MrSamialbeik

8 ай бұрын

@@nysewerrat6577 so what? Is he not allowed to look like someone having to go to the bathroom? You admited that he didnt interupt verbally, but aparently he has to look a certain Way while waiting to respond - otherwise its considered rude . 😂 the world doesnt have to adapt to your needs of what facial expression one has to have while waiting 😂.

@solklar885

6 ай бұрын

@@MrSamialbeik he didn't interrupt because he was repeatedly told not to right before...

Gross surely is a giant of physics but he should learn how to have a fair discussion letting the interlocutor speak

@PhilHalper1

2 жыл бұрын

yep fair point

I loved the comically barbed compliments of each other at the end: Carlo compares David to Einstein who was famously productive when younger but lost his way a bit in later years, David compliments Carlo on his endeavours in physical theory but says he is more impressive in his philosophical travails. A wonderful podcast indeed.

@PhilHalper1

2 жыл бұрын

thanks, yes I thought these were very funny on both Carlo and David' part

@mesokosmos2212

2 жыл бұрын

Catchy ending s'words, indeed!

@PhilHalper1

2 жыл бұрын

@@mesokosmos2212 Yeah i thought with were quite funny at the end

@JimEadon

2 жыл бұрын

Gross should know about philosphy, he doesn't do science. (As defined by Popper).

@annaclarafenyo8185

Жыл бұрын

David Gross is similar to Einstein in that he won the Nobel prize for one of his least significant contributions.

Thank you Phil for bringing this debate to us. I enjoyed it a lot but as a physicist i would have preferred you to let them go more into detail! Cheers

@PhilHalper1

2 жыл бұрын

Thank you for your comment. , I appreciate that but there are also a lot fp pope interested in physics but not physicists ,so i was trying to cater to them.

Taking a side with Carlo Rovelli. My doctrine is the Geometric Chronon Field Theory which share important properties with LQG. However, unlike with Ashtekar Variables, the deconstruction of spacetime comes from formalizing spacetime as a pair of observer and observed spacetime. The field starts with a scalar (not a coordinate) field of time which can be considered as emergent from 3D foliations. In some geometries, e.g. de Sitter, the scalar can be viewed as the maximal proper time between each event and an initial synchronization foliation. This foliation need not be unique and does not even need to be compact, however, there is a choice in FRWL manifolds that makes the choice meaningful. Since there can be more than one path to this 3D manifold measuring the same maximal proper time a single curve is not traceable and therefore the field is a scalar field and not a coordinate of time. See "Electro-gravity via Geometric Chronon Field and on the Origin of Mass in ResearcGate from 2022. This version is light years more advanced than the original IARD 2016 paper form 2017.

Carlo: calm, not fidgeting, listening more than interrupting, clear about the limitations of the theory he works on. David: irritable, moving unhappily, constantly talking over panelists, admitting almost NO criticism of StrnThr. One looks to me an open minded scientist, the other closer to “scientific arrogance”.

Wow great to see Gross & Rovelli go at it, thank you to all involved. It's interesting to see 2 very intelligent individuals have such different creative ideas/opinions about physics. I think such a huge & complex subject is hard to squeeze into 1 video. Perhaps a more structured format would of been better with it split over a few videos but i really enjoyed it thank you.

@PhilHalper1

2 жыл бұрын

you are welcome

Great job as an interviewer and mediator. But it would be nice if you allowed them to dive deep into the technical stuff so that we the layman can research further and learn. Thanks

@PhilHalper1

2 жыл бұрын

thanks

Professor Rovelli is such a gentleman.

@PhilHalper1

2 жыл бұрын

he is indeed

@ccmcgaugh

Жыл бұрын

I agree! 👍👍

So nice to hear them both talk about their path into physics and what woke their passion.

@PhilHalper1

2 жыл бұрын

i agree, you can hear more about Carlo's math here: kzread.info/dash/bejne/qm2eu6puhqysaag.html

@HyperFocusMarshmallow

2 жыл бұрын

@@PhilHalper1 Was the link right? It seemed to be about Singularity-theorems and the BGV-theorem.

@PhilHalper1

2 жыл бұрын

@@HyperFocusMarshmallow its at the beginning of that film

Very cool format. It was great to see them squirm in their seats trying to let each other talk! Love the tension. Its a wonderful change from the expert panels where everyone agrees.

@PhilHalper1

2 жыл бұрын

thanks, yes I find panel discussion pointless too.

@SEJay-gj2cv

2 жыл бұрын

Check out the Theory of Everything podcast with Curt Jaimungal. Same format although, instead of a debates he hosts theolocutions where guests are more encouraged to genuinely consider the other perspective and aren't anywhere near as arrogant, which is nice. :p

Wow you are getting some amazing guests lately! Love the debates! If I may attempt to constructively critique: you often asked the guests to “explain X bc people won’t know what that means”. 1) this wastes valuable time. It results in less info and less depth. We want to know what these titans think about deep things; we don’t need them to spend their time giving definitions off the top of their head when people can look up the precise definitions online. I imagine others are like me and are used to pausing to look things up and we want the nitty gritty technical conversation. 2) if someone really doesn’t know what a topic is, will a 10 second definition really be helpful for them to properly follow along? I think the majority of the time doing this is disruptive to the flow of the conversation and pointless in a time when we can pause YT and have Wikipedia access to get a general idea of any topic we are unfamiliar with. And for every person you are helping with these “explain X” stops, I wonder for how many of your viewers you are wasting their time.

@PhilHalper1

2 жыл бұрын

Ive had a few people say this, so i will reconsider next time . But i think a scientific American article eowuld explain these terms and that is the audience Im gong for , not just physics graduates.

@alexanderherbertkurz

2 жыл бұрын

@@PhilHalper1 I am with Phil here. The extra explanations are short enough and not disruptive. It is important for the non physicists in the audience to know that they are welcome. This is more important than how informative the explanation actually is. So well done Phil, from my point of view.

@bozo5632

2 жыл бұрын

Imho anyone who can follow the discussion at all will probably know the basics already, so I'm with OP.

@sakketin

2 жыл бұрын

@@PhilHalper1 Great physicists are typically great science communicators as well. They often have a unique way of explaining known phenomena so you can gain insight even if you already knew the subject they are explaining before hand. I wouldn't give this up in the future debates/interviews.

A very fundamental problem in quantum gravity is that the action in GR depends only on the energy/matter/momentum distribution, so when you have to consider all fields and physics going on to solve an isolated problem like quantum gravity in absence of a precise description of the fields and stuff in space you run into problems pretty fast, there is no way to separate what happens at high energy with gravity from what happens at high energy in qed or qcd for example, they are attracted at the hip in a tricky way.

@Achrononmaster

2 жыл бұрын

Gauge-gravity dualities do offer ways to tackle high energy - the bulk gravity is dual to low energy QFT on the boundary. The real problem being we do not live in AdS. So they are not "attached at the hip" more like attached head-to-toe

I came to this discussion since I follow Rovelli on social, so I’m biased towards his position. This was thoroughly run in the spirit of inquiry, IMHO., and thank you for always attempting to bring it to layman’s terms Thank you so much for organizing this stellar discussion- even of it did get Saturnian in parts, it’s been wholly illuminating 💡

@PhilHalper1

2 жыл бұрын

you are welcome, thanks for your comment

Thank you for these videos from actual physicist much more clarity than popular KZread videos trying to explain the issues within both

Thanks for this, I’m hoping to get into quantum mechanics later in life (I’m only 17 right now) and it’s great to see there’s plenty of discussion to be had if I get there. Also I think it’s great that you try to rephrase things in a way that the public can understand. I get that as a physicist it’s probably easy go down a rabbit hole of complex jargon but it doesn’t always make for good viewing. I hope you keep it up in the future :)

@PhilHalper1

2 жыл бұрын

thanks so much for your comment, good luck with your studies,

Despite the at times unruly disagreements the honesty of the arguments is unquestionable and shines through brightly, which made this an amazingly helpful discussion. Very well done for promoting such an interesting and valuable debate (Thank you from Portugal).

@PhilHalper1

2 жыл бұрын

you are welcome, glad you liked it.

Thanks for hosting these discussions. I love the channel. It must be hard trying to moderate the conversation with such big egos involved!

@PhilHalper1

2 жыл бұрын

You are welcome, yes it wasn't easy

Love this channel for the amazing content! Thank you! Onward, ever onward!

@PhilHalper1

2 жыл бұрын

thanks glad you like it

Interesting points. I wish you prevented David Gross from interrupting Carlo so often though.

@PhilHalper1

2 жыл бұрын

i wish I had too

@honeyj8256

2 жыл бұрын

David gross is notorious for interrupting, Nima was giving a lecture and David interrupted him so often it was cringe worthy.

@PhilHalper1

2 жыл бұрын

@@honeyj8256 I didn't know that

@honeyj8256

2 жыл бұрын

@@PhilHalper1 yes it was a lecture Nima gave at the Niels Bohr institute, check out the beginning, he interrupted him so often, I don’t know he stayed so cool . David Gross was being so argumentative. Bad behaviour from a Nobel laureate.

@PhilHalper1

2 жыл бұрын

@@honeyj8256 thanks do you have a link?

Excellent. For once a proper debate on string theory and to a lesser extent a good discussion on strengths and weaknesses of loop quantum gravity.

@PhilHalper1

2 жыл бұрын

thanks

Great discussion! Kudos to Phil for his knowledge and moderation skills!

@PhilHalper1

2 жыл бұрын

thanks

I am surprised about the 80-year-old man David Gross never misses a trick on these points. Excellent discussion! Tnx

@PhilHalper1

2 жыл бұрын

you are welcome

Very valuable. A bit too heated at moments; I don't like interruptions, even interruptions of interruptions; maybe a chess clock would help. Apart from that, good job - a good topic, a good choice of speakers and good interventions like requests to outline technical terms (e.g. holography, AdS, CFT, renormalization etc).

Thankyou Phil for bringing together two great explorers in this talk:)you are working really hard to bring us these kind of talks, thankyou:)

@PhilHalper1

Жыл бұрын

you are welcome

Thank you Prof Gross and Prof Rovelli for this exchange.

@PhilHalper1

2 жыл бұрын

couldn't agree more

It was one of the most enjoyable discussions in physics I have ever listened to. Really awesome idea and I would only hope that it will be continued in the near future

@PhilHalper1

2 жыл бұрын

thanks, yes planning more of these.

@ossiedunstan4419

2 жыл бұрын

Can`t respect any of you until you come to back to reality.

@thiagolucena4366

2 жыл бұрын

@@ossiedunstan4419 what do you mean by reality?

@wulphstein

2 жыл бұрын

@@thiagolucena4366 how about figuring out the mechanisms that make the laws of motion work.

@JimEadon

2 жыл бұрын

Actually, it's depressing. Gross is arguing in favour of a totally failed research programme. Nothing awesome about that. At least the LQG guy is honest.

Thank you for taking the time to put this debate together, may be a follow up with Carlo Rovelli would be interesting. English is not his first language which allowed David Gross an advantage. David should learn to turn off his email notification chime. It seemed a little intrusive.

@PhilHalper1

2 жыл бұрын

thanks for your comment and perhaps we will do another of this, there were so many topics we dint get around to

It was a nice debate. Thanx for this incredible video, appreciate it a lot!

@PhilHalper1

2 жыл бұрын

Thanks you are welcome. Glad you liked it

I can't claim to even come close to understanding this, but enjoyed listening to these scientists debate their ideas

@PhilHalper1

2 жыл бұрын

glad you like it

Great debate! Not as high quality as the Guth/Penrose one: as many comments noted, David was monopolizing the time, but that was to be expected from him; he probably does not realize that this actually does a disservice to his point of view. I also support the comments that it was not necessary to get them to explain "for laypersons" some of the terms they used; this just took up unnecessary time. In any event, looking forward to more debates of this kind.

@PhilHalper1

2 жыл бұрын

thanks for your comment.

@JFJ12

15 күн бұрын

As a layperson I strongly disagree with your opinion about laypersons.

Despite the session moving forth on a bumpy road, the conversation was very insightful to both sides for a complete layman like me.

Note that the Cosmological Constant "problem" is only a problem from a QFT perspective. In General Relativity its value is simply not surprising and it is not particularly. small. (The reason for that is that it is a _constant_ in GR and so in an expanding universe, where other densities shrink with time, its role will grow until it starts to dominate.)

I am watching the discussion after the fact (not live). As I listen to Prof. Gross say that string theory is like QFT, I am confused because my understanding is that string theory quantizes one dimensional objects (strings; position as function of parameter along the string and time) whereas QFT quantizes fields (field value as a function of space and time). In QFT a particle is a "wave" on top of the vaccum state of the field. On the other hand, I haven't seen strings referred to as excitations on top of some field. Also, in QFT there are virtual particles. Are there virtual strings?

@madeleinebirchfield7658

2 жыл бұрын

Well, one of the unfortunate developments over the past decade is that many string theorists have redefined string theory to basically mean "everything that self-identified string theorists do" rather than the string theory studied back in the 80s and 90s, with strings and higher-dimensional branes. So today, for example, self-identified string theorists frequently study conformal field theories, and they would argue that they are doing string theory, but CFTs are really a special class of QFTs rather than being a type of string theory. This arose because string theorists have largely failed to construct a string theory compatible with our universe and experimental evidence, and thus have moved on to other more fruitful ventures (CFT, holography, condensed matter, quantum information), but are for some reason unwilling to stop identifying as 'string theorists' and accurately label their current field of study.

@tharangamadhusankha

2 жыл бұрын

A)ADS-CFT duality act as a dictionary to translate from string theory to QFT. B) same can be used to translate back full LQG as a background theory, and on the string theory side arrive at a theory of network of closed strings serving as a background. A string and a loop can be the same wordvolume but interpreted with different Wilson lines. Whereas the corresponding QFT dwell on the surface of that worldvolume. C) Sometimes a pair of virtual particles can be interpreted as a short lived open string or a closed loop in time direction.

@jedomann

2 жыл бұрын

@@madeleinebirchfield7658 yes

@sambitsarkar5190

2 жыл бұрын

@@tharangamadhusankha any reference for point B?

@MH-mc3pp

2 жыл бұрын

You are misunderstanding the purpose of what is known as QFT (and it is forgivable, because there have been some culprits like Carroll and Tong who have gone around giving old-fashioned incorrect presentations on this point). So let me clarify: Even though it is described as "quantizing fields", that is a statement about a convenient mathematical description to help one understand local interactions between quantum PARTICLES. To put it differently, what people refer to as QFT is just a technical way of referring to the consistent unification of special relativity and quantum mechanics applied to particles. So Gross is right. String theory is analogous to more familiar physics. Instead of particles, it is strings, and both obey the rules of quantum mechanics. While the "field" is a convenient book keeping device to describe local interactions between large numbers of identical particles. Furthermore, there is indeed another mathematical subject known as "string field theory", where you might view a string as an excitation of a field. But remember, like particles, it is the strings that are fundamental. The fields are always pure formalism and never measurable, even in principle.

Super conversation, thanks.

@PhilHalper1

2 жыл бұрын

you are welcome , glad you liked it

I have an amateurish question: If there is a smallest distance and space is "pixelated", is there a force that binds those pixels together? Like the strong force with quarks?

@PhilHalper1

2 жыл бұрын

no i dont think so

@mikehipps1015

2 жыл бұрын

@@PhilHalper1 OK, thanks. And thank you for these videos!

@frun

2 жыл бұрын

Good point. It is not pixelated as far as physicists can tell: kzread.info/dash/bejne/oK2Exqt7nrq1c7A.html. Furthermore, i believe, what we perceive as an empty space is a conglomerate of particles.

@rohitkale6380

2 жыл бұрын

Great point. If they are seperate, there has to be one... Isn't it? Maybe that is the unified force we r looking for.

@BrettHar123

2 жыл бұрын

@@frun LQG has discrete eigenstates of area and volume, but they still transform over the groups SU(2)xSU(2) in a continuous symmetry which are a compact continuous group. The states simple cycle around and will appear continuous.like spherical harmonics. That is why LQG does not violate local Lorentz symmetry.

Brilliant conversation thank you

@PhilHalper1

2 жыл бұрын

you are welcome, flad you liked it

My favorite subjects outside of making music...awesome vid skydive!

@PhilHalper1

2 жыл бұрын

thanks

Wow, that will be great! I'm eager to watch it.

@PhilHalper1

2 жыл бұрын

cant wait for people to see it, it was pretty lively . let me know what you think

David just didn't understand that Carlo says that LQG is trying just to quantize gravity and doesn't turn off gauge bosons or matter and so on because it's just like Su(3) that's not unified to the electroweak part of the standard model. As a result LQG is consistent at this level. The other point is that there are arguments , very strong arguments, that LQG reproduces the classical limit of General relativity. So I agree totally with Carlo that string theory it's just useless. Wonderful mathematics but isn't supported by evidence in a concrete way: cosmological constant is positive and not negative, there's no supersymmetry that has been proven and a lot of problems with compactified dimensions. Calabi-Yau manifolds gives 3 complex dimensions, i.e. 6 more real dimensions, to add to the usual 4 dimensions of our space time that haven't been detected ever and probably will not be.

This was a fascinating discussion to me, and I liked the occasional explanations (I have basic scientific background but not to this level ^^). BTW, Carlo mentioned the time from the beginning of "strings" to now, but I think he could also talk about the time x number of people involved. It seems string theory has been pretty prolific in those terms (at least a lot of money has been assigned to researching it, hasn t it ?)

@PhilHalper1

2 жыл бұрын

thanks, happy you found it fascinating

@Achrononmaster

2 жыл бұрын

Yes, but absent actual corruption in NSF funding (granted there is some, but it's not horrific), the string people get more people because they attract more grad students, not just because funders like it better. If grad students fall out of love with M-theory it will not get so much funding. M-theory is a social movement. If it cannot produce more goods or if supersymmetry is ruled out then it'll die, but that won't be a bad thing nor will all the research done in the mean time. It gave rise to Gauge-Gravity duality, which will survive string theory, and that's a huge win for everyone. (Contrary to popular press, the bulk gravity theory does not have to be a SUSY string theory.)

@stevenverrall4527

Жыл бұрын

String theory is unconstrained to the degree that there are endless possibilities. It is a paper producing machine that earns physicists promotions. I think that's why it's so popular. Sadly, it could be the biggest waste of time ever devised by physicists. Similarly with the fruitless search for dark matter particles.

Great to have Skydivephil back. Debates are nice, but I prefer your pithier and more straightforward didactic pieces. I hope you get them up and running again soon. The graphics help along with the narrative

@PhilHalper1

2 жыл бұрын

Thanks. we have made a new documentary that we will premiere in the new year but I have another project that is not for youtube but is taking up most of my time. Im really excited about it and think you will be too but cant reveal any details yet

@AllanSegalMD

2 жыл бұрын

@@PhilHalper1 looking forward to the big reveal.....and the KZread documentary

Around -1:00 Prof. Gross says that AdS allows one to study "things in a box." But isn't the Minkowski background also homogeneous and isotropic? Of course I don't know the details so I can't tell what is so special about AdS that allows quantum gravity within it to be equivalent to a CFT in one less spatial dimension. In any case, conformal means "no length scale", right? But as far we know, there is a minimal length scale, the Planck scale and even in holography (the entropy of a black hole) the Planck area emerges.

A very illuminating discussion. Thanks for putting this together.

@PhilHalper1

10 ай бұрын

You are welcome

Well handled, Phil! With regards to criticism, I felt that David was more equipped with established mathematical results of string theory and Carlo responded to criticism with just ideas that are maybe in research but not in the literature.

@PhilHalper1

7 ай бұрын

thanks, glad you enjoyed it.

I found myself in a quantum loop of looking for knowledge finding Carlo’s book The Order of Time, and now this interview.

@PhilHalper1

Жыл бұрын

his other books are all very good too.

It was a very nice video. Thanks a lot.

@PhilHalper1

2 жыл бұрын

you are welcome, thanks for your comment

More, please!

@PhilHalper1

2 жыл бұрын

thanks, will try

I am really looking forward to this discussion. Nonsense type K12 on one side of the discussion and nonsense type B7 on the other side.

In my opinion the main advantage of Quantum Loop Theory over String Theory is that QLT ist (gravitational) background independent and String Theory is not !

Finally got through it! =P Good grief! Like slogging through waste deep mud. Need to go through another time to try to get the meat of it, but extremely difficult to get it off the bone, to separate the wheat from the chaff...very convoluted. Highly recommend Jim Baggott's book, Quantum Space to shed light on both LQG & String theory, the hstory & evolution of both, and who's who. Very well written, engaging, a great read. 👍😜👍

Its amazing we can hear Nobel laureates like this. Mind blowing.

@PhilHalper1

2 жыл бұрын

thanks

Phil, thanks for this, great discussion

@PhilHalper1

2 жыл бұрын

you are so welcome my friend

Even if one gave them an own youtube channel I do not think they would have soon come to an end; great moderating skill! Nevertheless, one or two follow-ups seem to be required.

its 23.30 here in India... let the fun begin..

@PhilHalper1

2 жыл бұрын

i hope you enjoy

Excellent moderation

@PhilHalper1

2 жыл бұрын

thanks, bt the way if you now anyone that can make arabic subtitles for any of our videos, please let me know .

amazing debate... enjoyed a lot

@PhilHalper1

2 жыл бұрын

thanks

Great discussion! It shows how much the communication between these communities is needed. I would like to see an episode devoted to noncommutative geometry, yet another very promising idea which extends the notion of the space to encorporate forces from Standard Model

@PhilHalper1

2 жыл бұрын

thanks for your comment and suggestion

This could have been great, but David did not allow any of us to really hear more about QFT. Carlo had to keep defending it, which did not allow me to learn what it was.

Carlo so feisty! Bit tense sometimes 😅 but sort of a little universe of science, intellectualism, passion, career, ego, culture, legacy (and oh yes physics and unified field theory) contained in one video. Great match up producing a seminal discussion that delineates the issues, conflicts and even confluences of these two, er, loops/strands of theorists.

@PhilHalper1

2 жыл бұрын

thanks for your comment

@ericac9634

2 жыл бұрын

@@PhilHalper1 Thanks for your channel!

@PhilHalper1

2 жыл бұрын

@@ericac9634 you are welcome

Quantum Entangled Twisted Tubules: When we draw a sine wave on a blackboard, we are representing spatial curvature. Does a photon transfer spatial curvature from one location to another? Wrap a piece of wire around a pencil and it can produce a 3D coil of wire, much like a spring. When viewed from the side it can look like a two-dimensional sine wave. You could coil the wire with either a right-hand twist, or with a left-hand twist. Could Planck's Constant be proportional to the twist cycles. A photon with a higher frequency has more energy. (More spatial curvature). What if gluons are actually made up of these twisted tubes which become entangled with other tubes to produce quarks. (In the same way twisted electrical extension cords can become entangled.) Therefore, the gluons are actually a part of the quarks. Mesons are made up of two entangled tubes (Quarks/Gluons), while protons and neutrons would be made up of three entangled tubes. (Quarks/Gluons) The "Color Force" would be related to the XYZ coordinates (orientation) of entanglement. "Asymptotic Freedom", and "flux tubes" make sense based on this concept. Neutrinos would be made up of a twisted torus (like a twisted donut) within this model. Gravity is a result of a very small curvature imbalance within atoms. (This is why the force of gravity is so small.) Instead of attempting to explain matter as "particles", this concept attempts to explain matter more in the manner of our current understanding of the space-time curvature of gravity. If an electron has qualities of both a particle and a wave, it cannot be either one. It must be something else. Therefore, a "particle" is actually a structure which stores spatial curvature. Can an electron-positron pair (which are made up of opposite directions of twist) annihilate each other by unwinding into each other producing Gamma Ray photons. Alpha decay occurs when the two protons and two neutrons (which are bound together by entangled tubes), become un-entangled from the rest of the nucleons. Beta decay occurs when the tube of a down quark/gluon in a neutron becomes overtwisted and breaks producing a twisted torus (neutrino) and an up quark, and the ejected electron. Gamma photons are produced when a tube unwinds producing electromagnetic waves.

Great Conversation. With some grit.

Why did David not work on unifying QED and QCD?

Hi, Phil! :) Can I ask you a little favor? I'm planing to make a high-quality video (2n part) defending Vilenkin's model of tunneling from nothing against critiques by apologists and others, and there is a paper criticizing his model which unfortunately wasn't mentioned in your video (Before BB 9), and this paper makes some strong points which need to be addressed if the defense is going to be complete. A long time ago I asked Vilenkin, but he did not reply (probably because he doesn't know me). But you know him, so would you mind briefly asking him what are some of his thoughts on the paper? I would appreciate immensely! The paper is _Comments on A Universe from Nothing_ by Ikjyot Singh Kohli.

@PhilHalper1

2 жыл бұрын

I appreciate what you are doing but i dont want to bother are interview subjects on every paper that comes out. I have spoken to him recently (in the lats year ) and if I do so again and i see an appropriate opportunity Ill try and bring it up

@CosmoPhiloPharmaco

2 жыл бұрын

@@PhilHalper1 Okay. Thanks, Phil! :)

Fascinating discussion. I have to say that Mr. Halper did a yeoman's job attempting to keep the debate on point, particularly with Mr. Gross's constant interruptions. His body language, in fact, was horrible. Mr. Roveli, by contrast, was far more gracious, and eventually did become frustrated. I think decorum would have gone a long way to make the debate even more informative and applaud Mr. Halper for his efforts to do just that.

@PhilHalper1

2 жыл бұрын

thanks, I wish I had interrupted a little more in hindsight.

@annettebonus2120

2 жыл бұрын

@@PhilHalper1 yes phil you did a very good job. But it was a set up. Roveli was gunning for Gross. The top dog. Haha "...the loopy guys..." Looking forward to Roveli explain why Loop Theory is superior....

@bendavis2234

2 жыл бұрын

@@PhilHalper1 How would you feel about muting their screens and only having one person talking at a time? Or at least having control over muting them when interruptions occur. I think that this would help the conversation be more understandable to listeners. Or would it affect the natural back and forth nature of the discussion?

@landroveraddict2457

2 жыл бұрын

Eloquent and accurate, well done that man,👍

@tim1883

2 жыл бұрын

From a physics standpoint, I think you are seeing Gross attempting to explain why he wasn't right about string theory. Of course without actually admitting it.

great conversation but damn David seems like such an opp. like he was just laughing and shaking his head whenever carlo was talking, not even open to what he was saying. i guess it's difficult for both of them to consider the merits of another theory when you've devoted decades to yours but idk david's attitude in particular was annoying guess im biased cuz im reading carlo's book Reality is Not What it Seems right now and that shit is fire. LQG for the win! let's see some evidence of black holes exploding babyyyy

@PhilHalper1

8 ай бұрын

I love that book, and I am glad you liked it too. Thanks for your comments btw.

Has the prediction of LQG that high energy gamma rays travel slower than 'c' been observed?

@PhilHalper1

2 жыл бұрын

that is not a prediction of LQG see our film on the subject here : kzread.info/dash/bejne/qm2eu6puhqysaag.html

@newolderalso2

2 жыл бұрын

@@PhilHalper1 The issue is addressed around the 1hr 1minute mark. The prediction is generic to theories of quantised spacetime.

@PhilHalper1

2 жыл бұрын

@@newolderalso2 Carlo talk about that here 57m 55 kzread.info/dash/bejne/qm2eu6puhqysaag.html

A funny thing to note is the fact that Rovelli's approach is that of a physicist who builds theories starting from solid foundations, the methodology used to build the mathematics that describes the LQG stems from a canonical quantization. The solution of the loops is the solution of the wheeler dewitt equation which gives a quantum interpretation to the GR. David Gross says instead that string theory arises from a mathematical formalism that solves the problems of infinity that you have working on a small scale, turns a mathematical tool that solves a calculation problem into the model of a theory, the funny thing is that Gross speaks of a classical derivation of his theory, but this is not true. The funny thing is that he doesn't believe it either, in fact he repeats it over and over again like a mantra. Congratulations to the moderator who directed the discussion flawlessly.

@youtubesucks1885

5 ай бұрын

no

Constructing the standard model in an LQG background is just a nightmare. Part of the reason is how LQG treats spacetime on quantization. Putting a quantum field on such a spacetime then requires additional non-local corrections to restore Lorentz invariance. While perhaps one can still force their way through but I believe inconsistencies won't really stop popping up. The construction itself does not feel natural. Strings on the other hand is surprisingly tightly constrained and yet works without putting anything by hand into the theory. It just feels as natural as QFT in its respective regime. Moreover string theory actually replicates features of standard model in surprising detail even without heavy analysis. Yes there's the landscape, but it can actually be shown to contain models with a cosmological constant as small as ours using Flux compactification. For those who don't know, compared to the Planckian units the observed cosmological constant is smaller by 10^-123. That's an insane small number and honestly has every right to just not be present had the number of string vacuas been small in the landscape given that string units are closer to Planckian units. But because of the large number of vacuas it does exist. Counting the microstates of blackholes in string theory actually gives the correct (in fact exact) value of entropy to zeroth order as was shown by Hawking and Bekenstein. Granted this has quantitatively been shown only for BPS blackholes but that is by no means a small feat. The same can't be said for LQG. The original calculation of blackhole entropy had to be done by fixing the Immirzi parameter and in fact by cutting out the entire interior, which sort of beats the point for me. I haven't checked the new calculations so can't comment on that. Out of all this I feel the biggest success of string theory has to be the deep understanding of dualities (AdS/CFT and holography being just one derived example). Via compactifications of a newer more powerful formulation of type IIB strings, called F-Theory, we can now study dualities between different types of quantum field theories, one of which the Montonen Olive duality, was predicted independent of string theory in 1977. Of course there's more application of dualities, specifically as David said in the holographic formulation of QCD. Another field which is at its infancy but I believe might have something of substance is a proposal of trying to understand deep learning using AdS/CFT. All of this would have been impossible without string theory. Finally supersymmetry isn't something string theorists (or even particle phenomenologists with realistic expectations) expect to observe at TeV scales of the LHC. String scale as I said is close to Planck scale, so the supersymmetry of strings lives in the Planck regime. I can keep on writing but I guess one really needs to study it for themselves to truly understand the essence of all this.

@PhilHalper1

2 жыл бұрын

thanks for your comment, they are very interesting. I really appreciate you taking the time to write.

@sambitsarkar5190

2 жыл бұрын

You're welcome :)

"The loopy guys" always crack me up

Hi from Portugal, amazing minds. ....

@PhilHalper1

2 жыл бұрын

welcome, yes they are

Great Discussion.

@PhilHalper1

Жыл бұрын

thanks

If this were a poker game, then I would be convinced that Gross is bluffing. If they made a huge bet against me at the poker table, then, based on body language “tells” alone, I would call Gross, but fold to Rovelli. (Meaning, I'm more inclined to believe that Rovelli's bet is honest, at least in his own mind.)

@Achrononmaster

2 жыл бұрын

Rovelli is a good guy, but good guys are not always playing on the winning team. FWIW I don't think either camp is correct. LQG does not have any other forces, so is a non-starter. If supersymmetry can be ruled out then strings are dead. To me, that'd be amazing exciting. Nothing better than seeing old white dudes with big egos get deflated and a new younger generation full of humility try to start over... and then grow old and acquire big dick-energy egos....

@JimEadon

2 жыл бұрын

@@Achrononmaster I was with you until you said, "old white dudes", which immediately makes me see you as the archetypal woke, bitter, virtue signalling, whites-hating, racist, ageist muppet. As you are not aware, the older generation achieved far, far more when they were *young* than later, lazy, woke, generations, and that will never change, because eduation is now way too dumbed-down, and the degeneration worsens as society drifts leftwards. Coming back to the physics, instead of your nasty little ad homs, LQG is background independent. But after decades of research, things are not looking great for LQG. String Theory DOES require a background, which is a killer-blow for ST. In addition, SUSY was not found anywhere, not at the LHC, nor in low-energy experiments looking for dark matter. String theoriests claimed it would be found. Oops! That means SUSY cannot the solution to forces unification. And that means, ST cannot be the solution to forces unification. And every single physicist knows it. String Theory is dead. Now, the LQC guys are extremely honest about the lack of progress in their field. String Theories are dishonest, and, instead of admiting total failure, they claim that everything is string theory, and that there must be a multiverse, which explains why String Theory has failed to explain our one. This is simply scientific fraud. "Acquire big dick-energy egos," - That's how you, yourself, come over. And me too, but at least I am aware :) Let's hope you acquire some humulity before you get old. Good luck.

I love these conversations because they promote free thinking and expose different nuances on the understanding of the substance. I 100% agree with David’s comment that what we are doing is looking at the same physical reality form a variety of perspectives. The experimental data determines the boundaries which any alternative perspective must remain consistent with. The Announcement of the Higgs Field was my interest awakening into particular physics and string theory. The perspective I choose to explore Presumes that there is only one prime component to the Universe, that being energy. However Energy exists in two forms, Dynamic Energy and Static Energy. The native form of Dynamic energy is infinite and dimensionless but in the presence of Static or Loop Energy Dynamic energy is constrained to the speed of light. The creation of the Big Bang in this perspective came about when Dynamic Energy spontaneously transitioned to Static energy and in the process Time and Space began. This perspective requires that Dynamic Energy and Static Energy cannot occupy the same space so the Universe is essentially an Energy Emulsion of Dynamic Energy immersed and constrained by a Static Energy field. Matter is effectively a quantity of Dynamic energy attempting to travel through the Static Energy Field but unable to do so due to the amount of it so it becomes deflected into a ball which becomes a quark. In this perspective Dynamic Energy can operate at above light speed within its containment and it is this feature which creates the perceived strong force. The dynamic activity of the particle imparts energy to the Static Energy boundary which affects the broad Static Energy field logarythmically and this energy is essentially Gravity. In this perspective Gravity is actually a repulsion created particles against the broad field of Static Energy. The more matter you have the greater the accumulated energy applied to the field So the Strong Force, the Weak Force and Gravity are all the same mechanism. Electro magnetism on the other hand is induced energy created by the tiny gap created by the geometry of the Proton’s quarks. This gap produces a flux tube loop which is essentially the Proton’s positive charge and the loop to which the electron attaches to the Proton. Magnetism is I suggest a similar induced flux tube created by the geometry of certain atomic Nuclei assemblies rather than a Nucleus on its own. To my thinking String Theory should be looking at the Quantum Field as a loop energy field rather than a wave field. There is no doubt that unconstrained energy wants to travel in straight lines as fast as space will allow it to, which we see when you smash particles in accelerators or nuclear explosions. So the nature of the energy within quarks is something that would rather be elsewhere and not confined. The essential understanding is the reaction between straight energy (Dynamic Energy) and loop energy (Static Energy) and how that reaction imparts energy to the field. The consequences of this are that the broad field effectively pushes matter together while also pushing bodies of matter apart creating the effect of universal expansion meaning the Dark Energy is effectively the Static Energy Field (Higgs Field), and I speculate further that Dark Matter is in fact Phantom Matter or areas of space with elevated field energy, free floating energy created by the collapse o Neutron Stars where the field energy can no longer contain particle energy and the particle containment expands to an event horizon containing the stars energy in the form of a black hole. In the transition energy goes in both directions some escaping to space and the rest to be confined by an event horizon, however in that transition I speculate the energy imparted to the field by the matter as particles becomes detached as the matter energy boundary area changes dramatically and the difference in confinement energy can relocate.

@PhilHalper1

2 жыл бұрын

thanks for your comment

Great to see two giants brought together and debate. Thanks for organising this as I don't think I've seen something like this on other channels besides promoting a particular theory from an expert. Science needs debates to iron out conflicts to move forward and gain concensus. However, this interaction was more a cussing game rather than each side taking away something new. For example, David made constant allegations that LQG doesn't have matter (which I've heard many times from String Theorists), yet Carlo corrected him that he was mistaken. This correction wasn't elaborated, nor acknowledged from what I coukd see from David, and so came across to not be willing to change his views. At least this debate was a start, and hopefully more to follow that helps collaboration between cutting edge physics.

@PhilHalper1

2 жыл бұрын

thanks Im glad you liked it

@bendavis2234

2 жыл бұрын

It would be great if these interviews were friendly and constructive conversations rather than a debate. People cling to their views when attacked. Plus, there wouldn’t be as much interruptions if they were on the “same side”, so to speak.

@jainalabdin4923

2 жыл бұрын

@@bendavis2234 The rather sad or funny thing is that both of these scientists are on the "same side" - the side seeking Truth. Yet act like their views are superior to each others, rather than working together more effectively.

Next deebate, Lee Smolin vs Leonard Susskind!

@PhilHalper1

2 жыл бұрын

I deinfitley want to do one sled on the anthropic principle so maybe they will be up for ti.

@isedairi

2 жыл бұрын

@@PhilHalper1 I hope, although I suspect Susskind will not agree to do it. Good luck!

@isedairi

2 жыл бұрын

@@PhilHalper1 Btw Phil you might wanna facilitate a debate between Lee SMolin and Jim Gates on string theory vs Loop Quantum Gravity. Somebody just posted a video of the most recent STRINGS conference where Veneziano, Gross, Witten and Gates basically just dismiss LQG.

Superb summaries by the host's choice of words. But, I don't think people who don't know the meaning of "observables" will be interested in watching the video up to the 1:21:10 mark. (Not that "observables" in quantum gravity are easy to define though). But still, I guess the audience might be smarter than the host occasionally thinks :p

@PhilHalper1

Ай бұрын

I think we have a variety of viewers and Im trying to cater to that variety but thanks for your comment

Should I be under the impression that a lot of Gross' criticism is outdated? Like the low-energy limit, fermions etc, which Rovelli said now have solutions in LQG, but sadly that idea wasn't expanded as well as stringy ideas such as the holographic principle for example. This didn't offer too satisfactory of an explanation of why they're against LQG since Rovelli's response to some of the most important objectives was "no, we now have a solution" or something like that. Okay, any further criticism on that solution? I wish they went into spinfoam theory at least a bit too, since apparently that's crucial to understand why LQG makes sense or potentially why it doesn't.

@PhilHalper1

2 жыл бұрын

i think thats right, a lot of the criticism of LQG is outdate but not all.

Superb !

@PhilHalper1

2 жыл бұрын

thanks

Darn, I know its hard to moderate but I just wished you would have given David more time to make his points.

@PhilHalper1

2 жыл бұрын

lol

As a layperson all I know is the jargon. String theory does not begin with Einstein's equations but yet produces a spin 2 massless particle, the graviton. However string theory's description of gravity is perturbative (around the Minkowski spacetime background) while LQG is "background independent." String theory incorporates all particles and interactions of particle physics, while LQG is about gravity/spacetime alone (though matter fields can be incorporated in the QFT way). String theory invokes supersymmetry (susy) which is under pressure due to lack of finding it at the energies of the LHC. However, susy may appear at higher energies or longer-lived decays. In some aspects strings and LQG seem to converge: the AdS-CFT correspondence and the Ryu-Takayanagi conjecture which pertain to a non-perturbative special case in string theory (??).

@PhilHalper1

2 жыл бұрын

all good points, Ill be interested to see what you think of the discussion.

@qgravy

2 жыл бұрын

You know WAY more than any "layperson"!

@CosmoPhiloPharmaco

2 жыл бұрын

@@qgravy He is a prodigious.

I've learnt that who speaks too much has not really important to say ... BRAVO ROVELLI 👏👏👏

There was lots of good stuff in here, but it would have been better if david would have let carlo get a word in edgeways. i'm not entirely convinced that this was particularly approachable for people who don't know about a lot of the advanced topics in modern physics. there was a *lot* of terminology. even a couple of things i'm going to have to go and look up before i rewatch it.

@PhilHalper1

2 жыл бұрын

I agree David did speak to much. if i could redo it I would have tried to do more about that. And yes I told Carlo and David to try and make it accessible to a Scientific American readership. but I think they were very excited to talk to each other and naturally they fell back to the language of professional physics.

@jameslaver4397

2 жыл бұрын

@@PhilHalper1 I think you did an admirable job trying to steer things, you just had a difficult job this time :)

@PhilHalper1

2 жыл бұрын

@@jameslaver4397 thanks

Foam is made of bubbles and bubbles are spheres. If you imagine spheres being inflated at the speed of light, and overlapping, then you can use such a model to describe spacetime.

Glad Rovelli went. Ill followed the idea since the loop representation of quantum general relativity by Ahstekar while studying beyond GR. All this years. I'm still convinced with LCQ than Strings. Btw. Are you still active on Physicsforum Skydivephil?

@PhilHalper1

2 жыл бұрын

no I haven't been on there in a while,

A step back should be done. There is absolute frame of reference, absolute time, local time in moving frame of reference. And that can be checked in experiment.

@lepidoptera9337

2 жыл бұрын

Good luck with that.

@matterasmachine

2 жыл бұрын

@Ju Kannstmima yes, they do change . Not only with speed but even with location on earth. That’s why northern hemisphere of earth is warmer than southern hemisphere. The only law that does not change is Lorentz transformation

@matterasmachine

2 жыл бұрын

@Ju Kannstmima Laws of physics exist to be disproved. If there was relativity and no real movement, temperature of hemispheres would be the same and the majority of hurricanes would not be in the northern hemisphere

I really love Carlo. Such a great person

@PhilHalper1

Ай бұрын

yes he is

Wish Carlo's patience to speak was more reciprocated .

@PhilHalper1

2 жыл бұрын

indeed

I always thought that listening directly to the scientific discussions is the best way to learn things, but this time I really felt the need of someone to condense and dumb down the topic. Because in order to truly enjoy this debate we'd need about four hours of the actual debate and about 5 years of proper education on the subject matter. Also from purely mundane point it was difficult to listen to both speakers (for different reasons)

@PhilHalper1

2 жыл бұрын

interesting a few people said I shouldn't have asked for explanations of anything!

@th3WhiteKnight

2 жыл бұрын

@@PhilHalper1 to think of it, I might just not be the target audience for this sort of debate. Not everything has be at the layman level.

I'd love to see next Carlo Rovelli Vs. Sabine Hossenfelder

@PhilHalper1

2 жыл бұрын

what would they discuss?

@aosteklov

2 жыл бұрын

@@PhilHalper1 i would like to see them talk about alternatives to sting theory and what they think about each other's research