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Qubism: self-similar visualization of many-body wavefunctions

Posted Dec16-11 at 07:18 AM by jrlaguna (Physics Napkins)

Take a look at this pic



We have devised a technique to plot quantum many-body states graphically, and we called it qubism. That image corresponds to the critical Ising model in a transverse field for a chain of 12 qubits. Nice, eh? :)

The preprint is already in the ArXiv. You can read more about it in Pysics Napkins or at the (under construction) qubistic web....
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Mathesis: a dependency network for science

Posted Jul3-11 at 05:41 AM by jrlaguna (Physics Napkins)

I'd like to present a novel project: the development of a "dependency network" for science.

http://physicsnapkins.wordpress.com/...7/01/mathesis/

The idea is the following: to design, collaboratively, a tree whose nodes are "pieces of knowledge" in science (not too small, not too big), linked among themselves with dependency relations. For each piece of knowledge, we would provide bibliography in order to learn it, much better if it is freely...
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Let me count the ways...

Posted Apr29-11 at 10:34 AM by jrlaguna (Physics Napkins)

Alice was so bored, waiting for a message from Bob, that she started to play with the five white rabbits she had got from the Queen of Hearts. She tried to figure out in how many ways she could split her rabbits in groups, like 5 = 4+1 = 3+2 = 3+1+1 = 2+2+1 = 2+1+1+1 = 1+1+1+1+1, so, for 5 rabbits, 7 ways.

She decided to count the partitions in which no group contained more than 3 rabbits… in our example, there are 5. And then, she counted the partitions with no more than 3 groups....
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Physics Napkins

Posted Apr8-10 at 03:38 AM by jrlaguna (Physics Napkins)

I started a few months back a blog in wordpress: http://physicsnapkins.wordpress.com. I'm thinking of moving my blogging activity here...

This image started it all:

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But, really, what is entropy?

Posted Apr7-10 at 06:41 AM by jrlaguna (Physics Napkins)

Entropy (1): the measure of disorder. The increase in entropy is the decrease in information.

Entropy (2): the measure of the energy which is available for work.

Problem: Reconcile both definitions.

Some people tell me that there is no problem here… Yet… I have the feeling that we call entropy to many different things because we have the intuition that, in the end, they’re all the same. My main problem: entropy (1) is an epistemological magnitude, whilst...
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