dvasya

Common sense quantum mechanics

Related to: Quantum physics sequence. TLDR: Quantum mechanics can be derived from the rules of probabilistic reasoning. The wavefunction is a mathematical vehicle to transform a nonlinear problem into a linear one. The Born rule that is so puzzling for MWI results from the particular mathematical form of this functional substitution. This is a brief overview a recent paper in Annals of Physics (recently mentioned in Discussion): Quantum theory as the most robust description of reproducible experiments (arXiv) by Hans De Raedt, Mikhail I. Katsnelson, and Kristel Michielsen. Abstract: > It is shown that the basic equations of quantum theory can be obtained from a straightforward application of logical inference to experiments for which there is uncertainty about individual events and for which the frequencies of the observed events are robust with respect to small changes in the conditions under which the experiments are carried out. In a nutshell, the authors use the "plausible reasoning" rules (as in, e.g., Jaynes' Probability Theory) to recover the quantum-physical results for the EPR and Stern–Gerlach experiments by adding a notion of experimental reproducibility in a mathematically well-formulated way and without any "quantum" assumptions. Then they show how the Schrodinger equation (SE) can be obtained from the nonlinear variational problem on the probability P for the particle-in-a-potential problem when the classical Hamilton-Jacobi equation holds "on average". The SE allows to transform the nonlinear variational problem into a linear one, and in the course of said transformation, the (real-valued) probability P and the action S are combined in a single complex-valued function ~P1/2exp(iS) which becomes the argument of SE (the wavefunction). This casts the "serious mystery" of Born probabilities in a new light. Instead of the observed frequency being the square(d amplitude) of the "physically fundamental" wavefunction, the wavefunction is seen as a math

20May 15, 2014

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Common sense quantum mechanics

May 15, 201420

To become more rational, rinse your left ear with cold water

A recent paper in Cortex describes how caloric vestibular stimulation (CVS), i.e., rinsing of the ear canal with cold water, reduces unrealistic optimism. Here are some bits from the paper: > Participants were 31 healthy right-handed adults (15 men, 20–40 years)... > Participants were oriented in a supine position with...

May 29, 20134

Risk aversion vs. concave utility function

In the comments to this post, several people independently stated that being risk-averse is the same as having a concave utility function. There is, however, a subtle difference here. Consider the example proposed by one of the commenters: an agent with a utility function u = sqrt(p) utilons for p...

Jan 31, 20123

[link] Innocentive challenge: $8000 for examples promoting altruistic behavior

A challenge recently posted on Innocentive seemed to me like something that may interest many LWers: "Models Motivating and Supporting Altruism Within Communities", with a grand prize of $8000. To quote from the challenge: > We are interested in looking at novel concepts from nature, business, or other areas that...

Dec 20, 20117

Review article on Bayesian inference in physics

A nice article just appeared in Reviews of Modern Physics. It offers a brief coverage of the fundamentals of Bayesian probability theory, the practical numerical techniques, a diverse collection of real-world examples of applications of Bayesian methods to data analysis, and even a section on Bayesian experimental design. The PDF...

Sep 19, 20119

Rationality Quotes September 2011

Here's the new thread for posting quotes, with the usual rules: * Please post all quotes separately, so that they can be voted up/down separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.) * Do not quote yourself....

Sep 2, 20119

Rationality Quotes August 2011

Here's the new quotes thread, for all those quotes you were going to post. Rules: * Please post all quotes separately, so that they can be voted up/down separately. (If they are strongly related, reply to your own comments. If strongly ordered, then go ahead and post them together.) *...

Aug 2, 20114

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Common sense quantum mechanics

A study in Science on memory conformity

Review article on Bayesian inference in physics

Rationality Quotes September 2011

dvasya

Common sense quantum mechanics

To become more rational, rinse your left ear with cold water

Risk aversion vs. concave utility function

[link] Innocentive challenge: $8000 for examples promoting altruistic behavior

Review article on Bayesian inference in physics

Rationality Quotes September 2011

Rationality Quotes August 2011

Common sense quantum mechanics

To become more rational, rinse your left ear with cold water

Risk aversion vs. concave utility function

[link] Innocentive challenge: $8000 for examples promoting altruistic behavior

Review article on Bayesian inference in physics

Rationality Quotes September 2011

Rationality Quotes August 2011

Common sense quantum mechanics

A study in Science on memory conformity

Review article on Bayesian inference in physics

Rationality Quotes September 2011