Fotini Markopoulou - Why is Quantum Gravity Key?

Quantum theory explains the microworld. General relativity, discovered by Einstein, explains gravity and the structure of the universe. The problem is that the two are not friends; they do not get along, they are not compatible. But they must. That's the task of quantum gravity.



Fotini G. Markopoulou-Kalamara is a Greek theoretical physicist interested in foundational mathematics and quantum mechanics. She is a faculty member at Perimeter Institute for Theoretical Physics and is an adjunct professor at the University of Waterloo.


Closer to Truth, hosted by Robert Lawrence Kuhn and directed by Peter Getzels, presents the world’s greatest thinkers exploring humanity’s deepest questions. Discover fundamental issues of existence. Engage new and diverse ways of thinking. Appreciate intense debates. Share your own opinions. Seek your own answers.

[longcastle]

Interesting that Kant proposed in the 18th century that time and space (and also causality btw) may not exist but just be constructs of the human brain. The template upon which we organize and experience the reality that is out there but which we can never know directly.

[SRAVALM]

Is nice how this channel posts videos that correlate with one another and uploading videos in relation to people's comments. Makes for a journey and is major in any research to find connections.

[david.thomas.]

Wow, she's a great speaker, very clearly explained. The idea of the curvature of spacetime affecting our experience of time and the quantum superposition of states inside a black hole is fascinating stuff.

[ZiplineShazam]

The Big Bang. . . Billions of Years of Evolution. . . Quantum Superpositions of Space-Time. . Quantum Field / Wave Function. . . and somehow we have ended up with things like . . ."Taco Bell" ?!?!

[marshallwright]

Look at life without the thought of time ( work, recreation, etc. ), Priorities. What I did, What I am doing now and, what I am planning to do. The mind has to organize in order to live comfortably and safely. Time is useless to a person who has to be nowhere any time soon! In the old days it was; See you in 2 or 3 Moons! Marshall Wright

[Robinson]

The supposed singularity is small and should therefore possibly behave quantum mechanically, but the diameter of a few miles that is the black hole and its mass is macroscopic: so why should it be possible to be in a superposition?

[PaulHoward]

They're finding paradoxes because gravitational theory is unnecessary and incorrect. All apparent motion is controlled by prāṇa, the power of choices in managing information systems.

[clemsonalum]

Emergence, she is spot on. Would mean that unification is actually not possible and just a rabbit hole.

[rgmartinez]

In other words... We do not have any idea

[drbuckley]

At what point does the quantum world give way to the classical world? What is the precise dividing line between the two?

[alejandrogarciaherrera]

Thank you! Make me think about the need for experiments with quantum time, but do we need to be able to go in the past? Thanks Fotini!!

[buddysnackit]

She is like every other physics "professional" completely wrong. So at 2:30 she says light gets sucked into a black hole. Wrong! Oh I'm wrong? Let's make a bet.
$1, 000 to anyone who can describe how a pull works. Not like a rope, but as in this case light being pulled into a black hole. And for the dumb people let me say your dumb answer ahead of time:

1.) It is gravity that does it!
2.) It is warped space!
3.) It has been measured!
4.) Dur....Tomato!

All of the above answers are OK but then you have to explain:

1.) How gravity works...which is what I was asking to start with.
2.) How does a nothing move a something.
3.) How a measurement reveals the mechanics behind it.
4.) Just having fun with #4.

Thanks

[RuneRelic]

1. Why assume that there are only two possible positions and/or states ? Rather then mutiple.
2. If quantum dynamics does not relate to time, why assume two+ places in one dimension rather than two+ dimensions at any moment in time ?
Especially if the quantum realm describes a snapshot in time rather than a sequence of time.

If we work on the assumption that mutiple states = mutiple dimensional possiblities outside of linear time
Then we must assume that multiple dimensions coexist at the same time.
Dream space vs conscious space.
After all, how can you decide on the 'best way' to achieve something physical, without exploring 'multiple' mental simulations beforehand ?

If your paradigm is that physical movement through space and other physical bodies is a thing, you reach one conclusion.
If your paradigm is that physical movement through space and other physical bodies is not a thing, and a subatomic transmutation relay exchange take place with adjacent particles, you reach another conclusion.
Its like an image moving across an LED panel by throttling the LEDs energy in sequence (apparent inertia) vs electrons jumping across the LED panels diodes in sequence (actual inertia).

In the 2nd paradigm, as all the subatomic field at the minutest level occupies a limited/fixed position, with energy/identity jumping across that fields components;
Those field componets can be throttled up and down into any position to represent any matter configurations fixed timeframe, and can therefore manifest as matter being in all places at once.
Thus inertia and identity cohesion, can still appear to collide and coalesce in the manner of sequential time.
Our reality, in such a realm, is nothing more than the probability that we deem the most certain configuration/frame, to follow on from the previous configuration/frame.
The imminent future and past comes with the greatest certainty, given inertia and template cohesion/integrity.
The remotest future and past comes with the least certainty, as inertia and cohesion/integrity at such a point can never be known.
The only certainty we have about the past, is by making 'assumptions' on this inertia and cohesion/integrity, just as we make 'assumptions' about the future.

Does localised concentration of matter and energy create gravity, or does the density of a quantum field attract mass and energy ?
If that quantum field is fixed position particles, where the highest density is the highest gravity, then harmonic resonance occupies far less space than disharmonic resonance.
If harmonic resonance is a factor, then inductance, capacitance and resistance is a factor at the minutest particles of the quantum field.
So not surpising to have entanglement really.

At the beginning, an energy pulse form the outskirts of the universe, can only ever coalesce at the center of that universe.
Given the nature between the cosmic web, static glass plasma balls and auto assembly of conductors, is it really so strange an assumption ?

[mlfilion]

Gravitational waves create space and time. Gravity is the fabric of space and time. Motion is time and gravity creates motion. Gravity equals energy and everything is energy. Gravity is the beginning and the end and the beginning etc. Gravity is the fabric of space, time, energy and mass. Just an idea, .which is energy. Lol

[julianmann]

Muddled thinking yet again. Einstein showed that there is no separate time, only a 4 dimensional space time continuum. The only modification required is for Backward Time, which operates at the Quantum level instead of classical time. So there is the concept of time at the quantum level, but not classical forward time. The reason why QM is described in probability equations is that we are classical forward time observers trying to interact with Backward Time at the quantum level. With regard to gravity, it operates in both forms of time, giving rise to the supposition of dark matter which we detect only by it's gravity. This form of matter is most likely antimatter, having survived Big Bang by means of an alternate quantum phase. Thus whereas normally matter and antimatter mutually annihilate in experiments in the Lab, the antimatter floating around in space is repulsive to matter and therefore keeps it's distance by means of mutual repulsion. I don't see how Gravity could have manifested itself before the CMB, which was when it started to form, hence there was no such force at Big Bang. It is unlikely therefore that there is such a thing as Quantum Gravity. If there was it would have dramatically altered the Big Bang model.

[Rebekka]

Did anybody understand anything she said? I was lost the very second she started to speak!, said it’s exciting, my head hurts

[brandonhodnett]

Trying to make gravity quantum is like fitting a round peg into a square hole. Gravity is NOT quantum.

[eugene]

Space travel (for people) is not possible. We will all stay on earth for ever. PERIOD, !

[eugene]

Universe means everything that exists. Therefore there is only one universe. PERIOD!

[davidrandell]

Gravity is the earth approaching the released object; Galilean relative motion. Real simple. Grow up