Schild’s Ladder

The Blue Room was packed from wall to wall; it hadn’t been so crowded since the Left Hand’s first trial run. The room was near the bottom of its module, and it had already been expanded as far as possible in all horizontal directions; several unobliging neighbors above prevented it from growing upward. As relations had deteriorated, some Yielders and Preservationists had swapped cabins in order to be surrounded by fellow partisans, but the Rindler hadn’t yet reached a state where every module was "owned" by one faction or another.

Yann paced the ceiling, ducking away from the tallest heads and shoulders — making his presence visible, but wisely desisting from trying to claim space that he could not defend with solid elbows. Other acorporeals came and went beside him, and no doubt he was conversing with some who weren’t bothering to display icons. Almost everyone who’d been born acorporeal had now donated their bodies to new arrivals, effectively splitting the Yielders into two distinct communities, more so in some ways than the factions themselves. Tchicaya had mixed feelings about this; their generosity had given many more people a chance to participate in events on the ship, in the only manner that would not have been alien to them. But the acorporeals had been willing to change modes in the first place, so why couldn’t the newcomers make do with software bodies? Maybe he had no right to think that way, having accepted the first such sacrifice himself, but the segregation by birth still depressed him, however well acclimatized to their condition the acorporeals were.

The Left Hand had scribed Yann’s state almost an hour before, and they were still waiting hopefully for an echo. Rasmah had ended up translating Yann’s purely algorithmic account into a kind of sophisticated scattering experiment: they were probing the far side by sending in an elaborately structured pulse that was capable of propagating relatively large distances. At least part of this pulse stood a good chance of bouncing off any structure that lay in its path, and coming back to them bearing an imprint of whatever it encountered.

This made it sound cozily familiar: a cross between radar, particle physics, and tomography. But the "distance" the pulse would travel and the "structures" it might or might not interact with were the raw topological details of an unknown superposition of quantum graphs, not properties of such elaborate near-side constructions as vacuum obeying Euclidean geometry, or the kind of matter that would reflect light or microwaves. Even the pulse itself had no real analogies in the ordinary world: it was not a particle, or a gravitational wave, or any kind of electromagnetic signal. It was a new form of dislocation in the pattern of threads from which all those mundane things were woven.

Rasmah cried out, "We’ve got something!"

People started jostling for a better view of the screen, though the image was being made available directly to everyone in the room. Tchicaya stubbornly stood his ground behind Rasmah for several seconds, then he gave up and let the crowd percolate around him, forcing him back.

He closed his eyes and saw, unobstructed, the first raw image of the returning pulse. It was a speckled, monochrome, pockmarked pattern, like a fuzzy shot of a cratered landscape, taken in such low light levels that you could count the individual photons. As he watched, the speckling of the image shimmered; it reminded Tchicaya of some kind of weird laser effect.

"Interference!" Yann crowed happily from the ceiling. "Wait, wait, let me — " An inset blossomed in the image, a huge, tangled, branching polymer, studded with loops and knots, built from nodes of every valence. Different parts of the pulse would have been modified in different ways by the same topology; Yann had used the interference between these altered components to reconstruct a typical portion of the kind of graph the signal must have passed through.

Rasmah said, "That’s far from an unbiased superposition. It’s not the sum of all random haystacks in there. There’s no vacuum, but there’s still order."

Tchicaya stared at the polymer. From childhood, he’d studied the Sarumpaet patterns, the quantum graphs that could maintain stability under the old rules. And for months, he’d seen the alternatives: all the different possible families of particles, deduced from the physics they’d trapped on the border.

This was like an amalgam that some magpie of a sculptor had created to sum up that experience, combining features from all of them — grabbing fragments of every kind of ordinary, vacuumbased physics and welding them together, without regard to such niceties as having to build a uniform, homogeneous geometry, or having to respect a simple set of rules that stayed constant over time.

Hayashi called out from behind Tchicaya, "Is that fractal? Can you give it a dimension?"