# Thread: The String Theory Landscape, Exchange Rates, and Perpetual Motion

1. ## The String Theory Landscape, Exchange Rates, and Perpetual Motion

Ok, from my understanding string theory posits that theyre are other possible vacuum states, other possible sets of values that universal constants could take, and that it's theoretically possible for different regions of space with different vacua to exist alongside each other (although if they had unequal vacuum energy the lower energy vacuum would tend to expand to displace the higher energy one.)

It occurred to me that if the speed of light is one of the values that can vary between vacua then it may be possible to create arbitrary amounts of energy without locally violating the first law of thermodynamics. Matter can be converted into energy and energy can be converted into matter, with the conversion rate being given by the famous formula E=mc^2, or equivalently m=E/c^2. Form this, it seems to me that on the side with the higher speed of light, each unit of matter will produce a greater amount of energy when converted into energy. Conversely, each unit of energy will produce more matter on the side with the lower speed of light. Therefore, if you converted matter into energy on the side with the higher speed of light, and then converted it back to matter on the side with the lower speed of light. Akin to a person converting their money from dollars to euros when the euro is down and then converting it back to dollars when the euro is up.

Now, besides the enormous practical issues of developing and funding the construction of such a device, there are three main possible issues I can see with this, but I don't know which, if any of them, actually apply:
1.) Is the speed of light even one of the things that can change between vacuums? I spent an hour and couldn't find anything online that addressed this specifically. IIRC the only constant that was ever mentioned specifically was the cosmological constant.
2.) It's very possible that the values would just correct themselves on the interface between vacuum states
2b.) If it did correct, would it just correct itself absolutely? This seems the most likely case, but is there any possibility that it might instead spit out additional particles of negative mass/negative energy density?
3.) How much energy would it take to keep the bubble of false vacuum from collapsing? It's possible that you;v have to spend all of your gains or more just to keep the thing running.

Any thoughts?

2. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Whenever you get this sort of result by moving something with a constant out in front from one context to another, what that usually means is that you've derived that there should exist a force that acts on that thing when you try to move it between contexts. So the conclusion here is that if you tried to move matter or energy across the boundary between two different vacuums, there would be either a force resisting that motion, or a force accelerating that motion, depending on whether the total energy would increase or decrease.

Similar to things like 'what if you put a wormhole with one end on the surface of a planet and the other far away, and drop an object over and over through that gravitational field?'. If you worked out the metric in detail, you should find that crossing the wormhole mouth to go from a low potential to a high potential should require pushing against a force that exactly accounts for the change in energy.

Or perhaps more down-to-Earth, there are forces such as the Marangoni force which arise from gradients of the surface tension on a surface (such as differences in chemical concentrations of surfactants) that arise from exactly this sort of balance.

3. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

This sounds suspiciously like the plot of The Gods Themselves...

4. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Originally Posted by NichG
Similar to things like 'what if you put a wormhole with one end on the surface of a planet and the other far away, and drop an object over and over through that gravitational field?'. If you worked out the metric in detail, you should find that crossing the wormhole mouth to go from a low potential to a high potential should require pushing against a force that exactly accounts for the change in energy.
Also, wouldn't something like a wormhole that's basically made out of gravity tend to override the ambient gravitational field of the area? Plus, if you've got a wormhole you've probably already got a perpetual motion machine anyway; if you could produce the requisite objects of negative mass, than you could also produce normal mass in arbitrary quantities. The conservation of mass/energy actually requires it.

In any case, I think that a better use of a wormhole would be to violate the second law. As I understand it, the second law of thermodynamics is more of a statistical thing than an absolute law. You'd need a very specific and rare configuration of atoms and energies for a shattered mug to suddenly reassemble itself, but almost any configuration will do for it to stay in pieces; that sort of thing. But with a wormhole we could conceivably constrain a system's possible configurations by arranging things so that the configurations we don't like would cause a temporal paradox, and therefore would have probability zero under the self-consistency principle.

5. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Originally Posted by Bohandas
In any case, I think that a better use of a wormhole would be to violate the second law. As I understand it, the second law of thermodynamics is more of a statistical thing than an absolute law. You'd need a very specific and rare configuration of atoms and energies for a shattered mug to suddenly reassemble itself, but almost any configuration will do for it to stay in pieces; that sort of thing. But with a wormhole we could conceivably constrain a system's possible configurations by arranging things so that the configurations we don't like would cause a temporal paradox, and therefore would have probability zero under the self-consistency principle.
I'm not sure I follow, If you want to limit probabilities all you need to do is to let's say put a "wall" that block some outcomes to materialize, but this will not impact entropy, as it will work as always in the remining "space". Additionally entropy refers to isolated systems so introducing any constrains "goes" around entropy but not exactly breaking it. Is there something I misunderstood from your description?

Moreover I would say thermodynamics being a statistical thing provides it an absolute law : ) Because this means that second law of thermodynamics is not some kind of observation but a logical result of randomness. Every random* event tend to go for the mean/expected value, as a result of simple rule that many different configurations have result that just looks the same and have the same mean. if you start throwing 10 dices, the result will usually be very close to expected values - when some dice will have higher result some other will have lower result.

*well, it depends on distribution but Central limit theorem, saves the day ! : )

6. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Originally Posted by Bohandas
Also, wouldn't something like a wormhole that's basically made out of gravity tend to override the ambient gravitational field of the area? Plus, if you've got a wormhole you've probably already got a perpetual motion machine anyway; if you could produce the requisite objects of negative mass, than you could also produce normal mass in arbitrary quantities. The conservation of mass/energy actually requires it.

In any case, I think that a better use of a wormhole would be to violate the second law. As I understand it, the second law of thermodynamics is more of a statistical thing than an absolute law. You'd need a very specific and rare configuration of atoms and energies for a shattered mug to suddenly reassemble itself, but almost any configuration will do for it to stay in pieces; that sort of thing. But with a wormhole we could conceivably constrain a system's possible configurations by arranging things so that the configurations we don't like would cause a temporal paradox, and therefore would have probability zero under the self-consistency principle.
There was a paper on relativistic billiards with wormholes, and one conclusion was that on the whole adding time travel tends to increase the number of possible solutions to the equations of motion rather than actually constraining things more. Classically, entropy cannot increase if you follow every degree of freedom, but in a classical system with time travel the universe has to end up in only one of the multiple equally valid solutions so entropy actually would increase because of that.

So you may well find an equivalent of the second law there as well, though the wormholes might permit some sort of non-local heat pump that lets you dump entropy out of the way easily.

7. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Ok, here's a thought experiment. The Cleromancy Machine. A machine is rigged up to measure the output of some non-deteministic quantum system, turn that into a number, and then check if that number is the solution to some problem that would otherwise entail time-consuming brute-force solving. If it is not the correct solution it sends a message back in time telling itself not to run the procedure (which was what caused it to send the message in the first place). In order to be consistent one of two things has to happen: either the non deterministic system spits out the right number or the machine spontaneously breaks, so the probability of NOT getting the right number on the first try becomes equal to the probability of the machine spontaneously breaking, which could be made arbitrary low with redundancies and by building the machine to be otherwise not dependent on quantum effects.

(the important question of course being if we could get the necessary number of redundant calculations to be less than the average number of iterations we'd expect to need for this type of problem)

8. ## Re: The String Theory Landscape, Exchange Rates, and Perpetual Motion

Originally Posted by Bohandas
Ok, here's a thought experiment. The Cleromancy Machine. A machine is rigged up to measure the output of some non-deteministic quantum system, turn that into a number, and then check if that number is the solution to some problem that would otherwise entail time-consuming brute-force solving. If it is not the correct solution it sends a message back in time telling itself not to run the procedure (which was what caused it to send the message in the first place). In order to be consistent one of two things has to happen: either the non deterministic system spits out the right number or the machine spontaneously breaks, so the probability of NOT getting the right number on the first try becomes equal to the probability of the machine spontaneously breaking, which could be made arbitrary low with redundancies and by building the machine to be otherwise not dependent on quantum effects.

(the important question of course being if we could get the necessary number of redundant calculations to be less than the average number of iterations we'd expect to need for this type of problem)
You could in principle build something like that, but that machine as described increases entropy (just the involvement of that non-deterministic quantum system, for example). It probably increases entropy a lot more than the Landauer bound for the calculation in most cases...

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