Филип Керр - The Second Angel

‘Shit,’ said Cavor, recovering the use of his prosthetic arm and then retrieving the gun from the floor.

A large hole in the wall ahead of them glowed bright yellow, lighting up the whole of the labyrinth behind and ahead of them.

‘Come on,’ Dallas said urgently, moving toward the glowing hole. ‘We’ve got to be away from here. Quickly.’

He took off on a slow-motion jog, each step lifting him two to three feet above the ground. Cavor followed suit, bounding past the glowing melted hole in the wall and around the next corner into darkness again. He was surprised to see Dallas going on.

‘If the robot can’t see in darkness, then what’s the problem?’ he asked.

‘Light merely activates the robot to search and destroy. But once it’s been activated, its second detector kicks in — a microwave sensor that generates an electromagnetic wave using the Doppler effect. [124] The Doppler effect describes the way in which stationary objects return a transmitted signal at the same frequency. Objects moving toward the transmitter return the signal at a higher frequency, whereas objects moving away return it at a lower frequency. It picks up anything moving toward or away from the sensor.’

Dallas paused at the next turn, and this time looked carefully around before moving again.

‘Anything else I don’t know about?’

‘No, I think that almost covers it.’

‘Almost?’ And then, as they came to a dead end: ‘Are we lost?’

‘No, we’re not lost,’ Dallas said irritably. He turned and placed his back against the labyrinth wall. ‘Only right now I think it’s better we have a solid wall behind us. That way we only have to pay attention in one direction. Just stand completely still and we might be okay.’

‘Shit,’ panted Cavor, breathing hard from his short exertion. He was beginning to feel tired. ‘I may not have a microwave detector, Dallas, but I can sense there’s something you’re still not telling me.’

‘Okay, here’s the problem. This thing is big. Fills the whole damn corridor. But it’s also fast. You try and shoot it as it’s coming toward you, it’ll beat you to the draw every time. So if we have to shoot it, we shoot it in the back. However, shooting it at all still leaves us with a problem. You can’t shoot it when it’s blocking the corridor ahead of us. Because it’s also heavy. It has to be, to operate at speed in microgravity. With all this gear on, we might never be able to squeeze past the thing. So if we shoot it at all, it will have to be in a place where it can’t block our route. What’s more, we can’t afford to miss. We shoot, and we shoot together on my say, understand?’

‘Understood.’ Cavor waited a second, and then added: ‘Except for one thing. How come the sensors miss out infrared? They get the visible wave band and then they get microwaves. Why not infrared? Infrared wavelength’s in the middle of those two, right?’

‘Nobel prize for physics, Cav. Yes, but microwaves are sensitive to temperature. That necessitates the robot having a dedicated microwave sensor, as opposed to one larger, cruder...’ Dallas stopped talking as, at the junction of the last route they had taken, a large black machine, taller than a man by half and almost twice as wide, appeared and then disappeared in total silence.

‘Was that it?’ asked Cavor. ‘What’s it doing?’

‘First it’s going to the light made by your UHT,’ explained Dallas. ‘Then it will take up the search from there.’

Traveling on hidden wheels, the stealth robot reappeared at the junction ahead of them and paused, as if deciding which way to move. It was as black as the walls of the labyrinth itself, its rectangular shape making it look like a large steel door. Cavor could see how this enormous object might end up blocking their way and breathed a sigh of relief as it turned and began to move in the opposite direction. But after only a few yards, it halted and then started to come back. This time it did not stop at the junction, but kept on coming toward them.

Pressed against the wall at the end of the route the robot had taken, Dallas gritted his teeth and said, ‘Keep perfectly still.’

‘It’s going to crush us.’

‘No, it won’t,’ Dallas insisted. ‘It’ll stop. Doppler effect. It measures distance the same way it measures movement. As far as it’s concerned, we’re just part of the wall.’

The robot was still moving toward them, seeming to be picking up speed.

‘If it keeps on coming, I’m going to be a part of the robot,’ said Cavor, and closed his eyes.

‘Don’t move.’

‘Where would I go?’

Opening his eyes again, Cavor found that the robot had stopped just a foot short of them. Now that he had a better view of it, he found that there were few, if any, features for him to observe. There was something that looked a lot like the robot’s photoelectric and microwave sensors, and something else that looked very like the barrel of a directional electrical conductor. The robot now remained motionless in front of them.

‘Are you sure it can’t see us, Dallas?’

‘It’ll move in a minute.’

‘Suppose it doesn’t. Suppose it stays put. How long can we wait here?’

‘It’s programmed to search for the intruders. It will move. Just stay still.’

‘I can do that. I only wish my atoms could do the same.’

God is in the atoms.

No, I’ll try to make it simpler than that.

The basic unit of matter is the atom, which itself is composed of a nucleus consisting of protons and neutrons surrounded by orbiting electrons. These unstable particles, these quantum objects, carry a positive or negative electrical charge and, spinning one way and then the other, exhibit a propensity to occupy different positions and to do everything at once. A superposition, if you like. Or whether you don’t like, actually, that’s what it’s called. A superposition is like God in that the quantum object occupying a number of different spin states simultaneously can be everywhere at once. A superposition is a kind of immanence. Without these superpositions, quantum objects would simply crash into each other and solid matter could not possibly exist.

Now, a bit is the smallest amount of information that a computer can use. Effectively it means the same as a quantum, which, as you already know, means an indivisible unit of physical energy. Anything smaller would be insignificant.

To make a quantum computer you need only store bits of information using quantum particles instead of chips, or transistors. We call these qubits, which is not the same as a cubit. That was a unit of biblical length used by Noah in his construction of the ark (no more footnotes, I think; not now that my hand has been revealed, so to speak). Qubits are based on binary logic: An electron spins one way, you give it the value of one; it spins the other way, you give it the value of zero. You might do the same with protons and neutrons, and in this way an atom might constitute a whole computer made up of several bits. Now when you take into account what has already been learned about superpositions, it should begin to be a little clearer how with just one atom, made up of lots of quantum objects, encoded with information, and occupying many different positions at once, a great many computations might be carried on simultaneously. In fact, a quantum computer with just eight bits would represent one billion coexisting computers, all working in tandem. Thus it may be seen that quantum computing amounts to nothing less than a completely new way of harnessing nature. As I have already stated, the answers have been found here, on the Moon, in comparative isolation from the rest of the universe, where the natural quantum dynamics of the said quantum computer — which I may now describe as myself — have been allowed to unfold.