Schild’s Ladder

Tarek went through the tunnel first, then Mariama. Tchicaya followed her. "Do you remember that playground?" he whispered. "With all the pipes?" She glanced back at him, puzzled, and shook her head. Tchicaya felt a stab of disappointment; he’d assumed that the sight would have triggered the same memory in her.

In the control room, Branco instructed the stylus. With his gravelly voice and deliberate singsong intonation, he succeeded in making every word drip with contempt, like a kind of sardonic poetry. "The phase relationships between the twelve TeV and fifteen TeV beams will be as follows." They really are making me read this aloud.

Tchicaya looked out the window, down at the immutable plane of light. He’d had vivid dreams about the border, imagining as he slept that the wall of his cabin was the thing itself. He’d hold his ear against it, listening for sounds from the far side, straining with his whole body, urging the signal across.

Sometimes, the instant before he woke, he’d see an iridescent film blossoming on the wall, and his heart would race with joy and fear. Did this new infestation mean that he’d been found out? Or that his crime had never really happened?

Branco looked up and announced with mock astonishment, "Am I finished already? Is that all I have to do?"

Tarek said, "For now. But I’m invoking my right to a functional audit."

"Hooray," said Branco. He pushed himself away from the control panel and floated by the window with his hands on his head.

Tarek took his place, and instructed the stylus to rise from the border. Tchicaya had heard about functional audits, but he’d never witnessed one before. A package of detectors, verified by the faction invoking the audit, was placed under the tip of the stylus, and the particles emitted were scrutinized directly, to be sure that they conformed to the agreed sequence.

Tchicaya was tempted to say something derisive, but he held his tongue. Whatever made Tarek believe that this was necessary, complaining about the procedure would do nothing to lessen his suspicions.

He used the handholds beneath the windows to drag himself closer to Mariama. "Where have you been hiding? I haven’t seen you for weeks."

"I have a lot of meetings."

"I go to meetings, too."

"Not these ones," she said.

She didn’t need to spell it out. She’d come to the Rindler hoping to work with Tarek on Planck worm design, and apparently the notion still wasn’t dead.

The novo-vacuum was already the largest object in the galaxy, and it was growing so rapidly that its surface area would increase almost forty-fold while it was encircled at the speed of light. Even if the Preservationists discovered a potential method for dealing with it, there was no prospect whatsoever of surrounding the entire thing with conventional machinery to administer the cure. The only practical tool would be a self-replicating pattern embedded at the level of quantum graphs, able to "eat" novo-vacuum and excrete something more benign.

To supporters of the idea, these hypothetical Planck worms would do no more than reverse the disaster of Mimosa. To Tchicaya, the symmetry was false. The places lost to Mimosa — ordinary planets, unique as they were — had already been thoroughly understood. Learning just enough about the novo-vacuum to infect it with a kind of fungal rot struck him as a corruption of every impulse that made intelligence worthwhile. He had enough trouble forgiving that kind of cowardice in a child.

"So what do you think the prospects are?" He meant those for Branco’s experiment succeeding, though if she cared to disclose her thoughts on anything further down the line, so much the better.

Mariama thought carefully before replying. "I’m almost persuaded that Sophus is right, but I’m not certain that Branco’s ideas follow. When we have no access to any particular far-side dynamics, even plucking out a random correlated state seems like too much to ask."

Yann had been floating a polite distance away, but the room was too small for any real privacy, and now he gave up pretending that he couldn’t hear them. "You shouldn’t be so pessimistic," he said, approaching. "No Rules doesn’t mean no rules; there’s still some raw topology and quantum theory that has to hold. I’ve reanalyzed Branco’s work using qubit network theory, and it makes sense to me. It’s a lot like running an entanglement-creation experiment on a completely abstract quantum computer. That’s very nearly what Sophus is claiming lies behind the border: an enormous quantum computer that could perform any operation that falls under the general description of quantum physics — and in fact is in a superposition of states in which it’s doing all of them."

Mariama’s eyes widened, but then she protested, "Sophus never puts it like that."