June 2009

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The Quantum Physics Sequence

This is an inclusive guide to the series of posts on quantum mechanics

lesswrong.com/lw/r5/the_quantum_physics_sequence/

Learn Quantum Theory in Ten Minutes

So you want to learn quantum theory in ten minutes? Well I certainly can’t give you the full theory in all its wonder and all its gory detail in that time, but I can give you a light version of the quantum theory in about that time.

scienceblogs.com/pontiff/2007/11/learn_quantum_theory_in_ten_mi.php

The Contextuality of Quantum Theory in Ten Minutes

Through my computer science “information is king” eyeglasses, there are really only two notions which thoroughly distinguish quantum theory from classical theories of how the world works: the nonlocal nature of quantum correlations as exemplified by Bell’s theoremand the much less well known contextual nature of quantum measurements as exemplified by the Bell-Kochen-Specker theorem.

scienceblogs.com/pontiff/2008/01/contextuality_of_quantum_theor.php

A new physical principle: Information Causality

It’s been a long time since I spent more than a few spare hours thinking about foundational issues in quantum theory. Personally I am very fond of approaches to foundational questions which have a information theoretic or computational bent (on my desktop I have a pdf of William Wootter’s thesis “The Acquisition of Information From Quantum Measurements” which I consider a classic in this line of interrogation.) This preprint is very much along these lines and presents a very intriguing result which clearly merits some deeper thinking.

scienceblogs.com/pontiff/2009/05/information_causality.php

Is Quantum Theory the Most Bastardized Theory of Physics?

I won’t go into a lot of stuff about quantum mechanics and what it’s like and so on…you’ve heard a lot of wrong things about it anyway!

scienceblogs.com/pontiff/2007/12/is_quantum_theory_the_most_bas.php

Visualizing a silicon quantum computer

We have developed a four minute animation as a tool for representing, understanding and communicating a silicon-based solid-state quantum computer to a variety of audiences, either as a stand-alone animation to be used by expert presenters or embedded into a longer movie as short animated sequences.

iop.org/EJ/abstract/1367-2630/10/12/125005/

Double-slit experiment

The double-slit experiment in quantum mechanics is an experiment that demonstrates the inseparability of the wave and particle natures of light and other quantum particles.

skullsinthestars.com/optics-basics-youngs-double-slit-experiment/

wikipedia.org/wiki/Double-slit_experiment

Everett’s Relative-State Formulation of Quantum Mechanics

Hugh Everett III’s relative-state formulation of quantum mechanics is an attempt to solve the quantum measurement problem by dropping the collapse dynamics from the standard von Neumann-Dirac formulation of quantum mechanics. Everett then wanted to recapture the predictions of the standard collapse theory by explaining why observers nevertheless get determinate measurement records (or at least appear to do so) and by accounting for quantum probabilities. It is, however, unclear precisely how this was supposed to work. There have been several attempts to reconstruct Everett’s no-collapse theory in order to account for determinate measurement records and quantum probabilities. These attempts have led to such formulations of quantum mechanics as the many-worlds, many-minds, many-histories, relative-fact, and bare theories. Each of these captures at least part of what Everett claimed for his theory, but each also encounters problems.

plato.stanford.edu/entries/qm-everett/

Decoherence and Ontology | At the most fundamental level, the quantum state is all there is.

An article by David Wallace about reductionism, emergence, and worlds in the many worlds interpretation of quantum mechanics — “At the most fundamental level, the quantum state is all there is – quantum mechanics is about the structure and evolution of the quantum state in the same way that (e.g.) classical field theory is about the structure and evolution of the fields.”

users.ox.ac.uk/~mert0130/papers/proc_dec.pdf

Four Things Everybody Should Know About Quantum Physics

scienceblogs.com/principles/four_things_everybody_should_k.php

Quantum physics is real. Probably the hardest quantum idea to accept is the notion of vacuum energy and “virtual particles”– stuff appearing out of empty space, then disappearing again seems almost too weird to credit. And yet the theory predicting virtual particles has been tested to a staggering degree of precision. One number in particular, the “g-factor” for an electron has been measured to be g = 2.00231930436146 ± 0.00000000000056, and every one of those 14 decimal places agrees with the theoretical prediction.

Seven Essential Elements of Quantum Physics

scienceblogs.com/principles/seven_essential_elements_of_qu.php

The previous collection of things everyone should know about quantum physics is a little meta– it’s mostly talking up the importance and relevance of the theory, and not so much about the specifics of the theory. Here’s a list of essential elements of quantum physics that everyone ought to know, at least in broad outlines…

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Introduction to quantum mechanics

Quantum mechanics (QM, or quantum theory) is a branch of physics dealing with the behavior of matter and energy on the minute scale of atoms and subatomic particles. Quantum mechanics is fundamental to our understanding of all of the fundamental forces of nature except gravity.

wikipedia.org/wiki/Introduction_to_quantum_mechanics

Summary of common interpretations of quantum mechanics

An interpretation of quantum mechanics is a statement which attempts to explain how quantum mechanics informs our understanding of nature.

wikipedia.org/wiki/Interpretation_of_quantum_mechanics

Quantum theory

Quantum theory may mean:

In science:

wikipedia.org/wiki/Quantum_theory

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YouTube EDU

“Quantum Physics” video results:

youtube.com/edu?edu_search_query=Quantum+Physics&action_search=1

“Quantum mechanics” video results:

youtube.com/edu?edu_search_query=Quantum+mechanics&action_search=1

Richard Feynmann Explaining Quantum Physics in Video

nextbigfuture.com/richard-feynmann-explaining-quantum.html

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Extra

Quantum simulators & super civilisations – University of Oxford

ox.ac.uk/media/science_blog/100120.html

A team, including Oxford University scientists, recently used a quantum computer to calculate the precise energy of molecular hydrogen.

I asked Jacob Biamonte from Oxford University’s Computing Laboratory, an author of the paper, about the work and what harnessing such ‘quantum simulations’ might mean for science and even the conquest of space…

Even More

Modern Physics: A Complete Introduction

k21st.wordpress.com/modern-physics-a-complete-introduction/

For the past two years, Stanford has been rolling out a series of courses collectively called Modern Physics: The Theoretical Minimum that gives you a baseline knowledge for thinking intelligently about modern physics. The sequence, which moves from Isaac Newton, to Albert Einstein’s work on the general and special theories of relativity, to black holes and string theory, comes out of Stanford’s Continuing Studies program my day job. And the courses are all taught by Leonard Susskind, an important physicist who has engaged in a long running “Black Hole War” with Stephen Hawking. The final course, Statistical Mechanics, has now been posted on YouTube, and you can also find it on iTunes in video. The rest of the courses can be accessed immediately below. The courses also appear in the Physics section of our collection of Free Courses. Six courses. Roughly 120 hours of content. A comprehensive tour of modern physics. All in video. All free. Beat that.

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