# Can computers survive bubble nucleations?

According to string landscape theory, our vacua with a cosmological constant of $10^{-123}$ is a metastable vacua which can decay to a supersymmetric vacua with either a zero or negative cosmological constant. However, such a decay is destined to happen sooner or later, but if we wait for it, it will happen at an unpredictable random location and time. Suppose we have some computer memories and computations that we wish to preserve through a bubble nucleation. Is it possible to engineer a controlled bubble nucleation to a supersymmetric vacua with an exactly zero cosmological constant, and construct computers with data storage such that the memories contained therein can survive the bubble transition to an entirely new law of physics unscathed, and the computers can also continue their computations?

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No-one knows, but see Louis Clavelli on "Susyria".

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OK, once again from wikipedia

The possibility that we are living in a false vacuum has never been a cheering one to contemplate. Vacuum decay is the ultimate ecological catastrophe; in the new vacuum there are new constants of nature; after vacuum decay, not only is life as we know it impossible, so is chemistry as we know it. However, one could always draw stoic comfort from the possibility that perhaps in the course of time the new vacuum would sustain, if not life as we know it, at least some structures capable of knowing joy. This possibility has now been eliminated. Sidney Coleman & F. de Luccia

further:

The possibility that we are living in a false vacuum has been considered. If a bubble of lower energy vacuum were nucleated, it would approach at nearly the speed of light and destroy the Earth instantaneously, without any forewarning. Thus, this vacuum metastability event is a theoretical doomsday event. This was used in a science-fiction story in 1988 by Geoffrey A. Landis,2 in 2000 by Stephen Baxter,[3] and in 2002 by Greg Egan.[4]

In a nutshell, no you cannot build an Ark to carry a computer because the whole structure and order of physical constructs as we know them will be destroyed, and computers and the structure carrying them are made out of matter as we know it.

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I bring you good news! There is hope! The Coleman-de luccia analysis assumes a vacuum state for the original and final vacua. This is a very good approximation for the inflationary epoch, but not for our current phase with its extremely small cosmological constant. Remember it's the difference in pressure which pushes the domain wall outward at close the speed of light in the Coleman-de Luccia analysis, but with such a tiny cosmological constant, even the cosmic microwave background or intergalactic gas is sufficient to counteract the difference in pressure. Ordinary matter and photons in our phase will bounce off the domain wall instead of passing through it, unless they have enormous kinetic energies. A future civilization will only need to create a very high grade vacuum with pressure less than the cosmological constant sealed in a box and create the new vacuum in it. This vacuum will expand until the domain wall hugs the walls of the box, and then, it will stop expanding. With a suitable choice of bombardment of ultra high energy particles to penetrate the domain wall, a computer can be reconstructed on the other side. Computations require a steady supply of free energy, and this requires the bubble to expand slowly. But the outside universe is safe. The bubble can't expand to reach galactic clusters because even dilute intergalactic gas has enough pressure to resist it. The bubble can only expand in the void between galactic clusters in the far future when the cosmic microwave background pressure has gone really down.

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are you talking of the supersymetric vacuum? How would you experimentally create a high grade vacuum with pressure less than the cosmological constant? I thought we are bound by the vacuum we find ourselves in. –  anna v Jun 28 '11 at 18:48

Have you actually computed the size of the bubble needed for nucleation to happen? If curvature effects are negligible, the minimum radius of the bubble ought to go as $\sim \frac{T}{\Lambda}$ where $T$ is the surface tension of the domain wall. Any smaller, and the surface tension and extrinsic curvature will cause the bubble to contract. If $T$ goes as $M_{Pl}^3$, this radius is supercosmological in the sense that it vastly exceeds the de Sitter accelerating universe radius $\sim \frac{M_{Pl}}{\sqrt{\Lambda}}$. Even if it's only $M_{GUT}^3$, it still vastly exceeds it. If you hope for the LHC to save you with a surface tension of $M_{TeV}^3$, you're still out of luck. Of course, at such scales, we do have to take curvature effects into account. In that case, a bubble the size of the cosmological horizon is sufficient. Do you seriously expect an advanced civilization can arrange for a simultaneous phase transition over the entire cosmological horizon? Dream on. If you're hoping for a Poincare recurrence to make that happen, that would take doubly exponential time, and by then all memory of our civilization would have vanished beyond any hope of recall. You want immortality? Here's news for you. All things are transient and impermanent and will pass away. From dust we come, and to dust we return. Remember we are born to die. We will be forgotten.

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This will be a very practical application to string theory in the future. String theorists can put that in their grant applications in the future. There are a couple of technical problems to solve first. We need to know which N=2 supersymmetric compactifications with a zero cosmological constant can support the possibility of open ended computation. Most likely, it requires the existence of a solid phase of matter. I don't see how else one can have a stable storage of information. This probably requires an excess of matter over antimatter to prevent a mass annihilation into radiation, the existence of fermionic particles as a crucial building block component to get the Pauli exclusion principle to prevent an overall condensation, and other factors which are probably physics dependent. It is up to future generations to find such a compactification.

Then, we need to find a way of engineering such a phase transition. Once again, this requires string theorists to find out the precise compactification of our phase, and also a mechanism to create exactly the new phase we want and not any other. Then, they need to find a way of seeding the new bubble with von Neumann replicators to take over, and finally, transmit a stream of information from our phase to the replicators in the new phase.

This will be a sign string theory has come into maturity. Who says string theory has no practical applications? This is why we need to encourage more research into string theory.

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