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19 posts tagged with physics *and* theory.

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## So, the unknowable kicks in

Logic hacking - "Writing shorter and shorter computer programs for which it's unknowable whether these programs run forever, or stop... the winner of the Busy Beaver Game for N-state Turing machines becomes unknowable using ordinary math - somewhere between N = 5 and N = 1919." [more inside]

## Reinventing Science

Science "explains things" in various ways. You can start with initial conditions, and apply laws of motion (classical kinematics). Or you can predict things via evolving probabilities (quantum mechanics). Or you can find emergent laws (thermodynamics). Or ... - There are many different

*modes of explanation*. Recently, David Deutsch invented a new one: Constructor Theory. [more inside]## The observer at the end of time: Of immortal watchers and imaginary data

In a Multiverse, What Are the Odds? "Testing the multiverse hypothesis requires measuring whether our universe is statistically typical among the infinite variety of universes. But infinity does a number on statistics." (previously) [more inside]

## there's nothing that is scientifically proven

## 21st Century Wiener

Norbert Wiener: The Eccentric Genius Whose Time May Have Finally Come (Again) - "The most direct reason for Wiener's fall to relative obscurity was the breakthrough of a young mathematician and engineer named Claude Shannon." [more inside]

## John Baez on the maths of connecting everyone (and everything) on earth

Network Theory Overview - "The idea: nature and the world of human technology are full of networks! People like to draw diagrams of networks. Mathematical physicists know that in principle these diagrams can be understood using category theory. But why should physicists have all the fun? This is the century of

*understanding living systems and adapting to life on a finite planet*. Math isn't the main thing we need, but it's got to be part of the solution... so one thing we should do is develop a unified and powerful theory of networks." (via ;)## binding the andat

Closing in on the twin prime conjecture (Quanta) - "Just months after Zhang announced his result, Maynard has presented an independent proof that pushes the gap down to 600. A new Polymath project is in the planning stages, to try to combine the collaboration's techniques with Maynard's approach to push this bound even lower." [more inside]

## My God, it's full of... everything

Revelations in the field of quantum physics have resulted in the discovery of the Amplituhedron, a jewel-like higher dimensional object whose volume elegantly predicts fundamental physical processes that took the brilliant Dr. Richard Feynman hundreds of pages of abstruse mathematics to describe.
The theoretical manifold not only enables simple pen-and-paper calculation of physics that would normally require supercomputers to work out, but also challenges basic assumptions about the nature of reality -- forgoing the core concepts of locality and unitarity and suggesting that space and time are merely emergent properties of a timeless, infinitely-sided "master amplituhedron," whose geometry represents the sum total of all physical interactions.

**More:**The 152-page source paper on arXiv [PDF] - Lead author Nima Arkani-Hamed's hour-long lecture at SUSY 2013 - Scans of Arkani-Hamed's handwritten lecture notes - A far more detailed lecture series "Scattering Without Space Time": one, two, three - Arkani-Hamed previously on MeFi - A hot-off-the-presses Wikipedia page (watch this space)## conservation of information

A Black Hole Mystery Wrapped in a Firewall Paradox - "A paradox around matter leaking from black holes puts into question various scientific axioms: Either information can be lost; Einstein's principle of equivalence is wrong; or quantum field theory needs fixing." [more inside]

## Perpetual Motion, maybe for real

Now, a technological advance has made it possible for physicists to test the idea. They plan to build a time crystal, not in the hope that thisNobel laureate Frank Wilczek's "somewhat embarassing" idea will be put to the test as scientists try to build time crystals.perpetuum mobilewill generate an endless supply of energy (as inventors have striven in vain to do for more than a thousand years) but that it will yield a better theory of time itself.

## "The game I play is a very interesting one. It's imagination, in a tight straitjacket."

From 1981 - 1993, documentary producer Christopher Sykes created three films about Dr. Richard Feynman. All are now available in their entirety on YouTube:

*Richard Feynman: No Ordinary Genius*,*The Pleasure of Finding Things Out*and*Last Journey of a Genius*(previously). [more inside]## "Apparently you can't hack into a government supercomputer and then try to buy uranium without the Department of Homeland Security tattling to your mother."

TV Fact Checkers "Behind every smart TV show, there is a tireless script coordinator, technical adviser, researcher or producer who makes sure the jargon is right, the science is accurate and the pop culture references are on-point." This week, Wired "is speaking with fact-checkers behind the fall TV season’s geekiest shows." [more inside]

## Position-based quantum cryptography theoretically proved

*Our results open a fascinating new direction for position-based security in cryptography where security of protocols is solely based on the laws of physics and proofs of security do not require any pre-existing infrastructure.*

## Quantum Mechanics: Myths and Facts

*Quantum Mechanics: Myths and Facts*(pdf), a recently-updated paper on the Cornell arXiv peer-review site. By Hrvoje Nikolić of the Rudjer Bošković Institute in Croatia. [more inside]

## Imagining the Tenth Dimension

Imagining the Tenth Dimension (Flash). 10th dimensional physics and string theory don't get any easier than this.

## handprint: watercolors & watercolor painting

i began cataloging the colors, and put the color list on the web. over time, the paint catalog turned into a web site.

## maybe the Sarumpaet Rules will be worked out afterall

Before the Big Bang - way,

*way*out of my depth, but I thought this comment was intriguing: "The paper as published, along with a longer follow up paper, looks to my untrained eye a nearly complete quantum gravitation theory, which is an exciting prospect in itself. However, as with all physical theories, we will await for experimental support before popping the cork." Here's some more on loop quantum gravity, spin networks, the big bang and*ekpyrosis*.## strung theory

"A theory that can't predict anything is not a scientific theory," Woit says. That would be string theory, which was going to be the theory of everything, but apparently can't even agree how many dimensions there are. "Those who dabble in alternate-universe speculations might be just modern versions of '16th century theologians (who) speculated that spirits and angels emerge from the extra-dimensional universe,' says Krauss, who is also an outspoken foe of creationist teaching in schools."

## (S/W)AP

Smolin vs. Susskind on the anthropic principle. For those keeping score: Stephen Hawking is for it. Brian Greene is not.

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