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review 2018-11-25 20:03
ΔE Δt ≥ ℏ/2: "Quantum Mechanics: The Theoretical Minimum" by Leonard Susskind, Art Friedman
Quantum Mechanics: The Theoretical Minimum - Leonard Susskind & Art Friedman


I was on a train the other week and I was sitting opposite Einstein who asked me if I would mind changing seats because he liked to see where he was going for a half a journey and then he liked to see where he had been for the other half of the journey and I told him I didn't mind changing seats and I asked him if he minded me asking him if he was dead and he said, "When?"

Why was the universe in such a low entropy initial condition? As many have pointed out, that might be even more unlikely than random macroscopic decreases in entropy. Also, if the universe had a low entropy initial condition, might it have a similar boundary condition at the other end? If so, then someday, entropy will start to decrease!

 

 

If you're into stuff like this, you can read the full review.

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review 2018-08-17 19:32
Gravity Curves Space-time. That’s It: "On Gravity: A Brief Tour of a Weighty Subject" by Anthony Zee
On Gravity: A Brief Tour of a Weighty Subject - A. Zee


“That space and time are replaced by spacetime immediately tells us how a field, be it electromagnetic or gravitational, varies in time once we know how it varies in space.”

In “On Gravity: A Brief Tour of a Weighty Subject” by Anthony Zee


“Einstein says the space-time is curved and that objects take the path of least distance in getting from one point in to another in space-time. The curvature of space-time tells the apple, the stone, and the cannonball to follow the same path from the top of the tower to the ground.”

In “On Gravity: A Brief Tour of a Weighty Subject” by Anthony Zee


“Gravity curves space-time. That’s it.”

In “On Gravity: A Brief Tour of a Weighty Subject” by Anthony Zee



On August 17, 2017 two neutron stars collide (Zee references this in his book). 

Let me hypothesize: consider a particle on the surface of one of the neutron stars belonging to a pair, about 10 km from the centre. It's being pulled downwards by an enormous gravitational force - about a hundred billion times stronger than gravity on the Earth's surface (if I calculated it right). But if the particle is going really, really fast (for example, close to the speed of light) it's still able to escape the star and not get pulled back in.

There's more stuff on the other side of the rainbow: you can read the full review.

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review 2018-06-23 19:08
Implausifiability in Physics: “Lost in Math - How Beauty Leads Physics Astray” by Sabine Hossenfelder
Lost in Math: How Beauty Leads Physics Astray - Sabine Hossenfelder


“The time it takes to test a new fundamental law of nature can be longer than a scientist’s career. This forces theorists to draw upon criteria other than empirical adequacy to decide which research avenues to pursue. Aesthetic appeal is one of them. In our search for new ideas, beauty plays many roles. It’s a guide, a reward, a motivation. It is also a systematic bias“

In “Lost in Math - How Beauty Leads Physics Astray” by Sabine Hossenfelder



One of the most obnoxious notions I’ve ever read in Physics is the one that purports that we’re a simulation. If it's all a simulation, why wouldn't the world that simulated us be a simulation too? This is the turtles all the way down idea. This doesn't mean it isn't true but it's also the same question as, if God created the universe and us, who created God? The answer I sometimes get when I say it’s all hogwash, is that the theory is aesthetically pleasing. Where is the evidence? And more importantly, is it “implausifiable” (I’m borrowing here Hossenfelder’s term)? The supposed evidence for our universe being a simulation seems to largely include the idea that if we extrapolate our technological progress further ahead in time, we will be able to build such a simulation ourselves *therefore* we are a simulation.

 

If you're into stuff like this, you can read the full review.

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review 2018-05-27 10:32
Quantum Ontology: "What is Real - The Unfinished Quest for the Meaning of Quantum Physics" by Adam Becker
What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics - Adam Becker

The Universal-Wave-Function vs. The Pilot-Schrödinger-Wave-Function vs. the Collapsing-Schrödinger-Wave-function as a Stab at Explaining Reality.

 

 

 

The diversity of possible comments on this book reflects ironically the Everett paradigm of quantum ontology. There are as many views of reality as there are observers. Thankfully in all instances, given the depth of some of the possible interpretations, the interaction of the observer state wave and that of the rest of the universe is extremely asymmetrical - the universe has a great effect on the observer but the latter's effect on the universe is mercifully, infinitesimally small. There is no doubt that the philosophical implications of the developments in modern scientific thinking are in lagging mode. This is because of the extreme complexities of the formalisms created to describe the reality as seen by human observers with a certain evolved sense of perception. The modern philosopher has to tread wearily through the theory before emerging tired and almost at wit's end to be in a position to even expound a valid opinion, least of all an emerging new philosophy, on the ontological basis of the quantum world. This is the first time I’ve read a book on Quantum Mechanics wherein three of the major outlier physicists appear: David Bohm, Hugh Everett III, and John Stewart Bell. 

 

 

If you're into the Measurement Problem in Quantum Mechanics, read on.

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review 2018-03-29 11:32
Follow-up on ∂S/∂t + H = 0: "Reality Is Not What It Seems" by Carlo Rovelli
Reality Is Not What It Seems: The Elusive Structure of the Universe and the Journey to Quantum Gravity - Carlo Rovelli,Simon Carnell,Erica Segre
"The world of quantum mechanics is not a world of objects: it is a world of events".
 
In "Reality Is Not What It Seems" by Carlo Rovelli
 
 
 
Rovelli is more than right to rail against the schism of art and science. Theoretical physics in some sense is the poetry of science; and science in its great evolution from the classical era on was intertwined with art (Galileo was a musician, Leonardo an anatomist and technological innovator; Piero was a geometer, while painters have ever worked at the edge of physics (light properties) and materials science (pigments and chemical properties), and so on).
 
 
 
If you're into Quantum Mechanics, read on.
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