QCraft: A Beginner's Guide to Quantum Physics in Minecraft [video] | Hacker News Reader

QCraft: A Beginner's Guide to Quantum Physics in Minecraft [video]

youtube.com

70 pointsMichaelAO12 comments

Not sure what I think of this. In particular, it seems to be hard-coding effects instead of deriving them from quantum-like rules.

This is particularly obvious if you watch the tutorial video for "quantum teleportation" [2]. Although there is a layout to building the teleporter, it doesn't seem to be related to how actual quantum teleportation is implemented. And the final effect is just a location changer, as opposed to the dual of superdense coding that can be used for fun things like "storing" quantum bandwidth [3].

To be fair, the video and the site[1] both mention this fact:

> qCraft is not a simulation of quantum physics, but it does provide ‘analogies’ that attempt to show how quantum behaviors are different from everyday experience.

I guess I'm just not sure what the goal is. It's a cool mod, but I feel like it will just contribute to the general confusion over what quantum mechanics is. People who use it will learn the names of some quantum things, but have only a vague or even misleading idea of what those things really are unless they go looking elsewhere.

1: http://qcraft.org/about/

2: https://www.youtube.com/watch?v=cebxtWnKx5k&index=4&list=PLU...

3: http://strilanc.com/quantum/2014/05/11/Storing-Bandwidth-wit...

Now practically speaking I've been playing on a server with qcraft in survival and found that its of little to no real use.

> Entangled (grouped) blocks are far to expensive, needing 12 (!) dust per entangled block which makes it impractical to build anything large with it. I find it a little less frequent than redstone.

> There is no compressed block of 9 dust like ALL vanilla ores have, which makes storing a bit annoying.

> The automatic observer that activates through a redstone signal only works from the sides not top/bottom which makes it more difficult/impossible to build any redstone activated structures.

> You cannot pickup once placed qcraft blocks, which is super annoying.

> only a few basic full-block types can be used as quantum blocks, no tile entities and no blocks from other mods (zero mod interoperability)

> the player portal is ugly and fixed to an even size (even multiblock structures are annoying) and why no teleport across dimensions, I mean its expensive enough

> ...

It seem to me this mod is very unfinished and not really made for survival nor created by people who actually play the game, and I think its annoying that it introduces its own ore into the world with such little practical use.

Now if anyone thinks thats too harsh of a critic, you need to realize how good minecraft mods have become, look a thaumcraft[1] for instance. The bar is much much higher now when it comes to mod quality.

[1] http://www.minecraftforum.net/forums/mapping-and-modding/min...

I'm wondering how observational dependence works when there are multiple observers. It would be neat if two observers could be seeing entirely different results. One could observe the cave lit, while the other observes it dark. I'm not sure how the engine could go about merging the two potentially very divergent versions of the world.

Shouldn't be too hard, all the rendering in minecraft is done in the client. All that needs to be done is tell client A to render state A and client B to render state B.

I was referring more to the actual algorithms. What if one observer sees a bridge and walks out onto it? Another observer doesn't see the bridge. Do they see the first person floating?

https://sites.google.com/a/elinemedia.com/qcraft/wiki/qcraft

"When an ODB resolves based on observation, it resolves to the same definitive state for all players in the world (even those players who did not perform the observation). Once an ODB is observed, it will remain in whatever state the observation yielded, until it is first no longer observed by anyone and then is observed by someone anew, at which time in will resolve again based on the observation rules"

So... don't look up while standing on the bridge, lest someone else look at it and cause it to disappear.

It doesn't appear that standing on a block counts as observing it, so yes. Also don't look back down if you looked away. Which makes it seem more like cartoon physics.

It would be interesting if standing on a block counts as observing certain properties of it, but not others. So standing on dirt means it could change to stone or wood, but not lava or water or make the block disappear.

Technically the entangled particles should be showing INVERSE states of each other, not the same state. But this looks amazing and makes me really happy, quantum needs to become mainstream.

Any quantum state that doesn't factor is "entangled". That includes both matching, inverse-matching, and more complicated states with more qubits like "last two qubits contain binary count of how many of the first three qubits are ON".

The state |00> + |01> + |10> + |11> factors into (|0> + |1>)(|0> + |1>) so it is not entangled. The state |00> + |11> doesn't, so it is entangled (in this particular basis).

Never ceases to amaze me what people can accomplish in Minecraft.

Note that this is Copenhagen interpretation. There are others, and at this time there's no way to tell which one is correct, if any.

Reply on news.ycombinator.com