A quantum processor, taking advantage of the qubit mutual superposition effects, should be able to solve O(n²) problems per single clock tick. Likewise, the universe -made up of quantum particles- should have the same computing power, being n the number of particles in the whole universe.

Nonetheless, aside from collapses, there is a fixed limit: the speed of light times distance. That means, two close atoms would process faster than two atoms with a light year between them.

More precisely, the top speed would be given by the number of possible collapses per second times the maximum distance in light seconds between the qubits involved in a given processor.

A fractal system which would use the fact that closer particles process faster, could actually process ¡faster than the universe!

At least at the level of problems not requiring more than a number of qubits divided by the simplification factor of whatever we would like to process. No quantum computer could possibly process the whole universe, as every next particle would require a n+1 higher complexity. Although, it would be an interesting experiment to calculate the possibility of calculating a simplified universe on a lower amount of particles. How much would the speed of light influence it? How bigger would be the increase than the decrease due to resolution?

The interesting part, though, is that with relatively small processors and a level of multiple abstraction good enough, it should be easily possible to simulate slices of reality big enough so the collapses would not differ much from those observed in the real world by those who live in it.

Compressed worlds, accelerated even though at a lower resolution. Would be like to live in them? The speed of light would be no obstacle, given that only the distance between simulating particles would matter, not the simulated ones. Even losing a big amount of resolution in the simulation process, it surely would be quite an interesting place.

But everything poses dangers -and not only social ones- as to much distance reduction could lead to, a black hole!

We think that inside a black hole, relativistic equations should be maintained, so from the point of view of a world simulated by particles in a black hole, there would be no speed increase; it would always be the same.

Will it be our future, to become a phantom world inside a black hole, with no possibility whatsoever to go back and escape the reality we would impose on ourselves?

Or, maybe, the evaporation effect would come to the rescue, letting us extract information from nano-scale black holes, making with them quantum processors at the highest possible speed.

Really, right now I would be glad to have a quantum processor with a few million qubits, if possible running at a few gigaflops, to solve a cool O(n³) problem I have in mind. Maybe in the next decade, the world of programming will be quite different.

One of the basic questions when choosing a digital camera, deciding at what resolution would we like our photos, or how to pint them, is the one about "how many Mpx is a human eye able to see".

Well, first thing would be to tell you that Mpx are an abstract unit, translatable to plain surface units, while the eye "sees" in units of spheric vision angle. To join both units, we need one more: the distance from the eye.

For example, if at a given distance the smallest point an eye can see has a width of 1cm, at double that distance it would not see anything smaller than 2cm in width, while at half the original distance will be able to distinguish points of only 0.5cm.

Once that is said, let's suppose a "normal" distance: 30cm from the eye. When we look at a printed photo that's more or less the normal distance, while on a PC screen it's usually more like 60cm or more, and on a TV it rarely goes below the 200cm (2 meters).

So with just that, we already can see that on a TV we barely make out points 6.66 times wider than on a photo, which -taking into account we are talking about both width and height- means we will see 44 times less points than on a photo. If on a printed photo we would see 44Mpx, on a TV we wouldn't see even 1Mpx.

Now, let's take a look at the eye.

Insinde the ete there are about 100 millon light detectors (100Mpx), but they aren't distributed homogeneously; over 30Mpx are at the fovea, on an circular area of about 15º in diameter. But even there are they evenly distributed, and we are talking about 30Mpx "monochrome". A photo is taken in 3 colors (red, green, blu), so the equivalent of the fovea would be arout 10Mpx.

At the eye there is another severe limitation: the optic nerve, with barely 1 million fibers. Clearly, you can't match 100M detectors t 1M fibers, so the information that gets transmitted is "pre-processed" inside the ete. Border detection, contrasts, relative colors and others, it's all done in the eye befor it even reaches the nerve (which is the reason behind some optical illusions). In the end, only 1M impulses reach the brain from each eye, even when we need to provide the eye with a bigger amount of points so they get converted in the right impulses.

To compensat, we have two eyes (2M impulses) and both are trembling all the time to get more detail from where there is none. In a way, the mind is constantly interpolating low resolutions signals, using the fact that they come from sensors with a much higher resolution. In the end, the brain is quite capable to capture about 2Mpx for each position that is looks at.

But... and this is the "big BUT"... ¡we rarely look at the same point for a long time!

Usually we first watch one place, then another, then one more... an thus all the time, scanning each image at a pace of 2Mpx for each position. Defects due to blurry vision not accounted.

So, the end result would be more or less:

A human sees abouit 2Mpx for every 15º of visual field diameter.

Applied to a photo, the upper limit would be at about 2Mpx in a 8x7cm area at a distance of 30cm, or in other words:

• ~6Mpx on a 15x10cm photo at 30cm (~500dpi)
• ~5Mpx on a 17" TV at 2m
• ~4Mpx on a poster at 2m to 10m (~40dpi)

Luckily, to appreciate a given photograph there is no need to reach these maximum levels, and we well might do well enough with 4 or even 16 times less. Even if it turns out to be less realistic