dvasya

• dvasyaJul 11, 2014, 8:25 PM

  12 points

  on: Too good to be true

  Was that “exactly 95% confidence” or “at least 95% confidence”?

• dvasyaJul 9, 2014, 7:06 PM

  2 points

  on: Meetup : Hous­ton, TX

  (I highly recommend that everyone join the Google Group so that we can all communicate in a single place by email)

  Does anyone else feel like trying to get this meeting a little bit more structured?

  For example, something as simple as brief but prepared self-introductions covering your interests (related or unrelated to LW) and anything else about yourself that you might consider worth a mention. We partially covered it last time but it was pretty chaotic.

  Or maybe someone even wants to give a brief talk about something they find exciting. Back in the day Jon used to educate us in computational neroscience, which was extremely interesting.

  Also, on getting there:

  The map in the post is not completely accurate, this is the actual location

  Parking on Main St (across from campus, from TMC to ZaZa

  Parking north of campus (Ashby/​Sunset area)

  $1 Stadium Lot (farther away)

• dvasyaJul 8, 2014, 8:57 PM

  1 point

  in reply to: dvasya’s comment on: Meetup : Hous­ton, TX

  Oh yes, and last time somebody discovered that there’s free parking on Main St across from campus (the stretch between Med Center and Hotel ZaZa).

• dvasyaJul 8, 2014, 8:18 PM

  0 points

  on: Meetup : Hous­ton, TX

  Hopefully, this time Valhalla should be open for, um, follow-up discussions. http://​​valhalla.rice.edu/​​

• dvasyaJun 18, 2014, 2:44 AM

  3 points

  on: The Power of Noise

  It seems that in the rock-scissors-paper example the opponent is quite literally an adversarial superintelligence. They are more intelligent than you (at this game), and since they are playing against you, they are adversarial. The RCT example also has a lot of actors with different conflicts of interests, especially money- and career-wise, and some can come pretty close to adversarial.

• dvasyaJun 12, 2014, 2:18 AM

  1 point

  on: Meetup : Hous­ton, TX

  Free parking is available in the small streets across Rice Boulevard from the campus (north of it). This is also closer.

• dvasyaMay 20, 2014, 4:04 PM

  0 points

  in reply to: Luke_A_Somers’s comment on: Com­mon sense quan­tum mechanics

  Here are some nice arguments about different what-if/​why-not scenarios, not fully rigorous but sometimes quite persuasive: http://​​www.scottaaronson.com/​​democritus/​​lec9.html

• dvasyaMay 19, 2014, 7:27 PM

  0 points

  in reply to: gjm’s comment on: Com­mon sense quan­tum mechanics

  I’m not sure if we can say much about a classical universe “in practice” because in practice we do not live in a classical universe. I imagine you could have perfect information if you looked at some simple classical universe from the outside.

  For classical universes with complete information you have Newtonian dynamics. For classical universes with incomplete information about the state you can still use Newtonian dynamics but represent the state of the system with a probability distribution. This ultimately leads to (classical) statistical mechanics. For universes with incomplete information about the state and about its evolution (“category 3a” in the paper) you get quantum theory.

  [Important caveat about classical statistical mechanics: it turns out to be a problem to formulate it without assuming some sort of granularity of phase space, which quantum theory provides. So it’s all pretty intertwined.]

• dvasyaMay 19, 2014, 4:58 PM

  0 points

  in reply to: DanielFilan’s comment on: Com­mon sense quan­tum mechanics

  Thanks! The list of assumptions seems longer than in the De Raedt et al. paper and you need to first postulate branching and unitarity (let’s set aside how reasonable/​justified this postulate is) in addition to rational reasoning. But it looks like you can get there eventually.

• dvasyaMay 19, 2014, 4:38 PM

  0 points

  in reply to: Luke_A_Somers’s comment on: Com­mon sense quan­tum mechanics

  Luke, please correct me if I’m misunderstanding something.

  The rule follows directly if you require that the wavefunction behaves like a “vector probability”. Then you look for a measure that behaves like probability should (basically, nonnegative and adding up to 1). And you find that for this the wavefunction should be complex-valued and the probability should be its squared amplitude. You can also show that anything “larger” than complex numbers (e.g. quaternions) will not work.

  But, as you said, the question is not how to derive the Born rule from “vector probability”, but rather why would we make the connection of wavefunction with probability in the first place (and why the former should be vector rather than scalar). And in this respect I find the exposition that starts from probability and gets to the wavefunction very valuable.

• dvasyaMay 19, 2014, 4:18 PM

  2 points

  in reply to: gjm’s comment on: Com­mon sense quan­tum mechanics

  I certainly would not rule out number 5 ;) As for 3, the arguments seem to apply to any universe in which you can carry out a reproducible experiment. However, in a “classical universe” everything is, in principle, exactly knowable, and so you just don’t need a probabilistic description.

  Unless there is limited information, in which case you use statistical mechanics. With perfect information you know which microstate the system is in, the evolution is deterministic, there is no entropy (macrostate concept), hence no second law, etc. Only when you have imperfect information—an ensemble of possible microstates, a macrostate—mechanics “becomes” statistical.

  Using probabilistic logic in a situation where classical logic applies is either overkill or underconfidence.

• dvasyaMay 18, 2014, 6:03 PM

  0 points

  on: Meetup : Hous­ton, TX

  Here is the Houston LW Google Group: https://​​groups.google.com/​​forum/​​?forum/​​houston-lesswrong#!forum/​​houston-lesswrong

• dvasyaMay 17, 2014, 5:33 PM

  0 points

  in reply to: DanielFilan’s comment on: Com­mon sense quan­tum mechanics

  Can this argument be summarized in some condensed form? The paper is long.

• dvasyaMay 17, 2014, 5:19 PM

  0 points

  in reply to: private_messaging’s comment on: Com­mon sense quan­tum mechanics

  I’m not sure I understood you well, could you please elaborate? If the triggering of detectors depends only on the (known) positions of detectors then it seems your experiment should be well describable by classical logic.

• dvasyaMay 16, 2014, 4:30 PM

  0 points

  in reply to: Shmi’s comment on: Com­mon sense quan­tum mechanics

  I guess one could argue that “bayesianism” (probability-as-logic) is testable practically and, indeed, well-tested by now. (But I still don’t understand how raisin proposes to reject physics in favor of probability theory or vice versa.)

• dvasya 16 May 2014 16:21 UTC

  1 point

  in reply to: Luke_A_Somers’s comment on: Com­mon sense quan­tum mechanics

  I’m not sure “not-MWI” is a single coherent interpretation :) Under Copenhagen, for example, the Born rule has to be postulated. The present paper

  does not support the Copenhagen interpretation (in any form)

  MWI also postulates it, see V_V’s comment.

  As for the paper’s assumptions, they seem to be no different than the assumptions of normal probabilistic reasoning as laid out by Cox/​Polya/​Jaynes/​etc., with all that ensues in regard to relevance.

  (edit: formatting)

• dvasya 16 May 2014 16:04 UTC

  6 points

  in reply to: ESRogs’s comment on: Com­mon sense quan­tum mechanics

  In short, they mostly seem far-fetched to me, probably due to a superficial reading of the paper (as Mitchell_Porter admits). For example:

  I also noticed that the authors were talking about “Fisher information”. This was unsurprising, there are other people who want to “derive physics from Fisher information”

  The Fisher information in this paper arises automatically at some point and is only noted in passing. There is no more derivation from Fisher information as there is from the wavefunction.

  they describe something vaguely like an EPR experiment … a similarly abstracted description of a Stern-Gerlach experiment

  The vagueness and abstraction are required to (1) precisely define the terms (2) under the most general conditions possible, i.e., the minimum information sufficient to define the problem. This is completely in line with Jaynes’ logic that the prior should include all the information that we have and no other information (the maximum entropy principle). If you have some more concrete information about the specific instance of Stern-Gerlach experiment you are running then by all means you should include it in your probability assignment.

  They make many appeals to symmetry, e.g. … that the experiment will behave the same regardless of orientation. Or … translational invariance.

  Again, a reader who is familiar with Jaynes will immediately recognize here the principle of transformation groups (extension of principle of indifference). If nothing about the problem changes upon translation/​rotation then this fact must be reflected in the probability distribution.

  hope that some coalition of Less Wrong readers, knowing about both probability and physics, will have the time and the will to look more closely, and identify specific leaps of logic, and just what is actually going on in the paper

  • in fact this is what I was trying to do here.

• dvasya 15 May 2014 23:41 UTC

  4 points

  in reply to: Shmi’s comment on: Com­mon sense quan­tum mechanics

  Thank you. The title plays on the idea of deriving quantum mechanics from the rules of “common-sense” probabilistic reasoning. Suggestions for a better title are, of course, welcome.

  In my view this is not so much “QM foundations” or “adding to physics” (one could argue it takes away from physics) as it is an interesting application of Bayesian inference, providing another example of its power. It is however interesting to discuss it in the context of MWI which is a relatively big thing for some here on Less Wrong.

  Regarding testability I’m reminded of the recent discussion at Scott Aaronson’s blog: http://​​www.scottaaronson.com/​​blog/​​?p=1653

• dvasya 15 May 2014 20:38 UTC

  8 points

  on: [Link] Quan­tum the­ory as the most ro­bust de­scrip­tion of re­pro­ducible experiments

  Here’s a condensed summary of the paper’s main points:

  http://​​lesswrong.com/​​r/​​discussion/​​lw/​​k88/​​common_sense_quantum_mechanics/​​

• dvasya 15 May 2014 20:29 UTC

  2 points

  in reply to: Emile’s comment on: Com­mon sense quan­tum mechanics

  Thanks. Took me a while to write the post.