The Fractal Prince

‘I see you are a quick learner, too. So what are you doing here?’

Matjek gets up and walks a few angry steps towards the sea. ‘I could tell them about you, you know. The other chens. They would cut you out.’

‘If they caught me,’ the thief says.

Matjek turns around. The thief is looking up at him, squinting his eyes at the sun, head cocked to one side, grinning.

‘Tell me about the last time,’ Matjek says.

‘Ask me nicely.’

Matjek is about to tell the thief what he thinks, that he is a figment of Matjek’s imagination and Matjek does not have to ask him anything. But the thief is so full of mirth, like a little Buddha that Matjek’s mother used to have in her garden, that the words die on his lips and he takes a deep breath instead. Slowly, he walks back to the towel and sits down, hugging his knees.

‘All right,’ he says. ‘Tell me about how they caught you the last time. Please.’

‘That’s better,’ the thief says. The sun is barely more than a golden wink in the horizon now, but he still puts his sunglasses on. The sunset spreads out in the sea, like flowing watercolours. ‘Well. It’s a story told against death, like I am, like you are, like we all are. Did anyone ever teach you that?’

Matjek gives him an impatient look. The thief leans back and grins at him.

‘Here’s how it goes,’ he says. ‘On the day the Hunter came for me, I was killing ghost cats from the Schrodinger Box.’

All around them, the dream vir begins to paint the thief’s words with the sunset, sand and sea.

1 THE THIEF AND THE BOX

On the day the Hunter comes for me, I am killing ghost cats from the Schrodinger Box.

Q-dot tendrils like sparks from a Tesla coil trail from my fingers into the little box of lacquered wood floating in the middle of my cabin. Behind it, displayed on one gently curving wall, is the Highway – a constantly flowing river of spaceships and thoughtwisps, a starry brushstroke in the dark. A branch of the gravitational artery through the Solar System our ship, Perhonen, is following from Mars to Earth. But today, I’m blind to its glory. My world is the size of a black box, just big enough to hold a wedding ring, the mind of a god – or the key to my freedom.

I lick sweat from my lips. My field of vision is a spiderweb of quantum protocol diagrams. Perhonen’s mathematics gogols whisper and mutter in my head. To help my all-too- human senses and brain, they translate the problem into yosegi: opening a Japanese trick box. The quantum protocols are sensations, imperfections and valleys in the marquetry, pressure points inside the wood like tense muscles, faint grins of sliding sections. I need to find the right sequence that opens it.

Except that here, the trick is not opening it too early, the wood patterns are hidden in the countless qubits inside – each zero and one at the same time – and the moves are quantum logic operations, executed by the arrays of lasers and interferometers the gogols have built in the ship’s wings. It all amounts to what the ancients called quantum process tomography: trying to figure out what the Box does to the probe states we ease into it, gently, like lockpicks. It feels like trying to juggle eight-side Rubik’s cubes while trying to solve them at the same time.

And every time I drop one, God kills a billion kittens.

The gogols light up a section of the diagram, red threads in the tangle. Immediately, I can see another section that is linked. If we rotate this arrow and that state and apply a Hadamard gate and measure—

The imaginary wood beneath my fingers groans and clicks.

‘Sesame,’ I whisper.

Drathdor the zoku elder liked to talk, and it wasn’t that hard to get him to explain what a Box was (without letting on that I had stolen one from their zoku twenty years ago, of course).

Imagine a box, he said. Now put a cat in it. Along with a death machine: a bottle of poison, cyanide, say, connected to a mechanism with a hammer and a single atom of a radioactive element. In the next hour, the atom either decays or not, either triggering or not triggering the hammer. So, in the next hour, the cat is either alive or dead.

Quantum mechanics claims that there is no definite cat in the box, only a ghost, a superposition of a live cat and a dead cat. That is, until we open it and look. A measurement will collapse the system into one state or the other. So goes Schrodinger’s thought experiment.

It is completely wrong, of course. A cat is a macroscopic system, and there is no mysterious intervention by a magical observer needed to make it live or die: just its interaction with the rest of the Universe, a phenomenon called decoherence, provides the collapse into one macrostate. But in the microscopic world – for qubits, quantum-mechanical equivalents of ones and zeroes – the Schrodinger’s cat is real.

The Box contains trillions of ghost cats. The live cat states encode information. A mind, even, a living, thinking mind. The Box qubits have been rotated into a limbo state between nothingness and existence. The mind inside would not notice anything – a set of quantum gates can let it continue thinking, feeling, dreaming. If it stays inside, all is well. But if it tries to get out, any interaction with the environment will bring the Universe down on it like a ton of bricks and collapse it into nothingness. Bad kitty, dead kitty.

‘So what do you put in a Box like that?’ I asked Drathdor.

‘Something very, very dangerous,’ he said.

A section of the Box in the qubit map we have created over the last week lights up like a city at night. I can feel it: the unknotting that always comes with a job when you discover the flaw in a lock or a security system or a con mark’s mind. Eagerly, I close my eyes and follow the flow of moves. The wood panels slide beneath my fingers. The gogols sing with the joy of the orgasmic jolts of pleasure they receive from computing spectral sequences of Hilbert space operators. More light in the map. The lid moves, ever so slightly—

And snaps shut. The next register dies, for good. The protocol network ties itself into a knot. The last measurement shows only death. I have destroyed another fragment of the contents of the Box.

I swear and throw the accursed thing across the cabin. The q-dot tendrils tear and dissolve. The Box bounces from the starry field of the wall and spins in the air.

The words that have been ringing in my head for days come back to me.

I am not Jean le Flambeur.

A small white butterfly lands deftly on the Box and brings its spin to a halt, fluttering its wings.

‘Before you break anything,’ the ship says in its soothing, feminine voice, ‘I would like to point out that this was all your idea.’

The ship is right: it was my idea. Or, rather, my earlier self’s idea. The original Jean le Flambeur, a thief and mind burglar of legend, an all around nice guy. Who left me with nothing apart from a few fragmented memories, old enemies, a prison sentence – and the thing inside the Box.

‘Touche,’ I say.

‘That’s three days straight now, Jean. Maybe you should leave it alone for a while.’

‘There is no time. You told me it’s decohering.’

Fatigue stings my eyes like sand. A reminder that, in spite of appearances, I am not free. Perhonen’s captain Mieli stubbornly refuses to give me root access to my Sobornost-made body, keeping it firmly within baseline human operating parameters in spite of my assurances that my previous attempts to escape our involuntary partnership were misunderstandings and that I am firmly committed to paying my debt of honour to her and her elusive Sobornost employer. Honest.

But I can’t give up. When the ship first examined the Box, it found that the quantum information inside is short-lived. In a few days, the kittens will die of old age.