Deriving general relativity from quantum measurement - Seth Lloyd

Seth Lloyd of MIT delivers a lecture: Deriving general relativity from quantum measurement at the QFQI Conference, Decoherence & Friends, May 2013.
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[@jxchtajxbt53]

Seth has a keen eye. Everything he researches is interesting. Loved the photosynthesis talk as well.

[@nacho74]

+Andrew Pa Time isn't measurable, events and measurement units like flips are

[@davidwilkie9551]

..great lecture, and from another point of view, the tuning of the clock oscillator to the space time structure, relative to the universe as a whole, is a generalization of "mass curves space"; and thank you for the simple explanation of what Rieman achieved along those lines.

[@gewinnste]

Since he talks so naturally about things falling into black holes, could somebody explain how this can happen at all? I thought to an outside observer, anything falling toward a Schwarzschild-radius will slow down and come to a rest at the horizon? Or is it that the increase in time dilation and the increase in velocity exactly cancel out and give a proper non-zero value? Help would be much appreciated. Thanks!

[@grandpaobvious]

As I understand it, the object will not only 'slow down' but will also be red-shifted to the point where it is invisible against the background.

[@gewinnste]

No, that's been discussed before: The redshift is important to what is perceived, but irrelevant to what really happens! It's the same for special relativity: You can accurately and instantly calculate where a far away object is from your perspective (frame) and how time passes there from your point of view (frame), even though you are not able to SEE the result up to the point where the light from that object reaches you, maybe years later.

[@sherlockholmeslives.1605]

The gravitational force of the black hole warps space in an area around it, like a stream of water, at some point the still water become shifting due to the pull of water downstream, or something like that anyway. You are perhaps best looking at documentaries that explain it more simply, like Brian Greene or Brian Cox.

[@tim57243]

It takes finite time from the viewpoint of the participant to fall into the singularity at the center. The apparent slowing down and coming to rest at the event horizon is an artifact of how the coordinates are defined in the Schwarzchild metric. The Wikipedia article about the Schwarzchild metric explains this and gives other metrics that don't have this property.

[@christianfunintuscany1147]

Very interesting and surprising !

[@drewmandan]

Hey guys, don't forget there's beer at 5:00...Only at UWaterloo would people be drinking at 5pm and need to be reminded of it.

[@JoschaBach]

1. Would that imply that the universe is shrinking, and more so in areas where you have more ops? Or how is that offset? 2. Light does not undergo state changes while traveling, i.e. should not perform ops, and thus it cannot contribute to curvature of spacetime. Does Seth Lloyd make a different prediction than Einstein here, or am I missing something?

[@davidfuller1061]

Yes, It would appear Shrinking would be the correct answer Using Bulk Modulus actually is a pretty good work around adding mass to the Elastic Medium drops the Oscillation Speed which drops the energy carrying capacity (redshifting all energy transitioning the mass loaded portion of the Medium ). SR & GR would already apply because the Medium itself is electromagnetic Like the loosening of a guitar string, Hubble constant would be releasing of initial stretch of the Medium, a homogeneous & isotropic Contraction of the Elastic Medium, while (the speed of the effects of light & Gravity) would be equal to the P-wave wave .... S-wave verses P-wave. The fastest wave, and therefore the first to arrive at a given location, is called the P wave. The P wave, or compressional wave, alternately compresses and expands material in the same direction it is traveling. The S wave is slower than the P wave and arrives next, shaking the ground up and down and back and forth perpendicular to the direction it is traveling. And it gets around the Speed limit of light for calculating the properties of the Medium. Speed of light = ( total system speed ) - (Hubble speed * 8^0.5 ) (3e+8 - 2.997935248198935e+8) / (8^0.5) = 73000 ((800000 / 8.88888888888e-12)^0.5) = 3e+8 137*73 = 10001 Bulk Elastic Properties & Wave Speeds (Elastic Property / Inertial Property)^0.5 = Velocity ((1 / ((4 * pi) / (10^7))) / 8.8541885e-12)^0.5 = 299792446.448 hyperphysics.phy-astr.gsu.edu/hbase/permot3.html hyperphysics.phy-astr.gsu.edu/hbase/Sound/souspe2.html#c1

[@jxchtajxbt53]

I believe it was the clock that was radiating and making state changes. Light self-radiation (vacuum polarization) is higher order QED effects which were not incorporated into the model hence the non-appearance of the cosmological constant.

[@ozdergekko]

It's way above my knowledge to really understand this, but it would help to know what "ops" are. changes in quantum states?

[@DerGastAusDerZukunft]

+ozdergecko elementary computations

[@ozdergekko]

+DerGastAusDerZukunft -- Danke und schöne Weihnachten!

[@grandpaobvious]

Yes, changes in quantum states. He says this twice, I think.

[@NomenNominandum]

Isn't this derivation somewhat circular? It is based on the formula for the Schwarzschild radius of a black hole, which, as Seth explains, cannot be properly derived from Newtonian gravity, thus requiring General Relativity. What I find intriguing is that the geomtric limit formula leads to the right order of entropy of the universe (contrary to QFT, string theory, holography, etc.), hence solving the "cosmological constant problem". So maybe it does make sense to add area ...

[@stevenytcx]

Thats why he divided it into two parts. The first part he motivates the limit and at the beginning of the second part he explicit ask the audience to forget everything he says before and start just from this limit. In other words we can take the geometric limit as our starting postulate or axiom

[@buttegowda]

If i take a proton and completely convert to energy, what happens to its charge?

[@pendalink]

what do you think of as the physical process you call "completely turning a proton into energy"

[@lincolnuland5443]

"doubling the size of the universe every planck time" You can do that forever if you wanted to...😉

[@StephenPaulKing]

"total energy determinable to the local vacuum" defines the upper bound!

[@stevenytcx]

seth lloyd 's style reminds me a lot of feynman. great explainer

[@daujok1301]

Quantum geometric limit that's cool!!

[@mixolydian2010]

Seth is the nearest physicist to the character of Rodney Mckay off Stargate i have seen.

[@NomenNominandum]

Einstein about his deepest insight: "People before me believed that if all the matter in the universe were removed, only space and time would exist. My theory proves that space and time would disappear along with matter."

[@fayaraben]

I am grateful for all of the lecture dear Seth Lloyd, but very much mathematical expressions are limiting the strong interests of others on this important theories of physics out of your classroom though it is practical for the lecturer.

[@damonbates6004]

are you complaining about math in an MIT lecture?

[@fayaraben]

@@damonbates6004 i do not know interest and level grade of his audience and popular you tube watchers. So i can not answer.( Note: math is a language helping researchers to express scientific, natural phenomena events etc. Law ,finance sociology psycho issues can also be expressed by logical, mathematical terms aritmetical processes too )

[@shiddy.]

very good +sub

[@zaidsserubogo261]

Upgrading quantum measurements to general relativityyy

[@PaulHigginbothamSr]

Now if he would just derive string theory particle values from quantum measurements we would actually get summers.

[@sommi888]

*seth lloyd is the most hung lecturer at MIT*

[@devilisahomo]

How hung? How deep did you receive him?

[@efegokmen]

Not quite

[@vladimir0700]

Seth is a little strange -- especially that laugh he has

[@tymonfrelik6758]

lol

[@KipIngram]

This is good stuff - I'm re-watching. Lloyd really is a kind of goofy character - I've never seen anyone quite like him before.

[@bobquick8587]

www.relativitychallenge.com/ Try it, you'll like it ! Seems like the math for the spherical wave front unicorn fart didn't work all the time........ Among other problems... Don't get me wrong ! It's a useful approximation, but that's all.

[@PaulHigginbothamSr]

Getting relativity measurements from quantum measurements is a backwards proof concept we all use in math and physics. Now get the string theory equivalents so we can successfully teleport and use interstellar drives to make Venus habitable by moving the co2 to Mars making it also earth human useable.

[@subramanyam2699]

Did this guy just derived General relativity from Quantum mechanics!!

[@lvitch]

Interesting lecture, but regurgitation without understanding. So it's impossible that everything in the universe is happening at the same time consistently.... smh.

[@devilisahomo]

Regurgitation without understanding is the norm these days. Misinterpretation is a big issue. If youre capable of completely understanding this topic youre also capable of seeing its flaws as you did. Glad theres more of us out there.

[@KipIngram]

This guy sounds kind of like a "mad scientist..." That laugh is weird. :-)

[@schmetterling4477]

Quantum measurement requires an underlying geometry... so he claims to derive geometry from geometry. I am calling bullshit on this.