Schild’s Ladder

The single graph on the wall was just a useful shorthand for the state they were hoping to create; the novo-vacuum itself was the sum of equal parts of forty-eight variations of the target graph, all generated by simple symmetry transformations of the original. All the individual variations favored one direction over another, but the sum combined every possible bias, canceling them all out and giving rise to a perfectly isotropic state. Since none of the graphs could be found in nature, this elegant description was useless as a recipe, but it wasn’t hard to show that the same state vector could also be described by a different sum: forty-eight regions of ordinary vacuum, each slightly curved, oriented in forty-eight different directions.

Inside the Quietener, an asteroid’s-mass worth of helium had been cooled into a Bose-Einstein condensate, and manipulated into a state where it was equally likely to be found in any of forty-eight different places. These alternative locations were distributed across the surface of a sphere six kilometers wide. Ordinary matter — or any kind of matter interacting with the outside world — would have behaved as if each distinct position had already become the sole reality; if a swarm of dust particles wandering by had made themselves part of the system, or if the helium’s behavior en masse had merely hinted at the detailed motion of its own atoms, then that behavior could only have told half the story — the classical half — and all the quantum subtleties would have been lost in the fine print. But the condensate was isolated as scrupulously as any cycling Qusp, and it had been cooled to the point where the states of all its individual atoms were dictated completely by its macroscopic properties. With no hidden complications, inside or out, the result was a quantum-mechanical system the size of a mountain.

The geometry of the vacuum in the Quietener inherited the helium’s multiplicity: its state vector was a sum of the vectors for forty-eight different gravitational fields. Once the condensate’s components had all been nudged into place, the quantum geometry at the center of the sphere would be equivalent to the novo-vacuum, and a new kind of space-time would blossom into existence.

That was the idealized version: a predictable event in a known location. In reality, the outcome remained hostage to countless imperfections and potential intrusions. If the experimenters were lucky, sometime over a period measured in minutes, somewhere over a region measured in meters, a few thousand cubic Planck lengths of novo-vacuum would be created, and survive for an unprecedented six-trillionths of a second.

Yann turned to Cass. "Are you ready to freeze?" The first time he’d asked her this, she’d been almost as nervous as the moment before she’d been transmitted from Earth, but the question had rapidly become a formality. Of course she was ready. That was how things were done. Just a few minutes of numb immobility, watching the data appear on the screen in front of her, and the odds were good that it would be the last time. A five-hour trip back to the station, a day or two of analysis, a brief celebration, and she would depart. Her Earth body, frozen more deeply than this one had ever been, was waiting for her. She’d step across the light-years in a subjective instant, a new set of memories to sweep away the icy cobwebs of her old self.

She said, "No. I’m not ready."

Yann looked alarmed, but only for a moment. Cass suspected that he’d just conferred privately with someone better able to guess what she had in mind. Though the Mimosans didn’t think any more rapidly than she did — running on Qusps themselves, they faced the same computing bottlenecks — they could communicate with each other about five times faster than her own form of speech allowed. That only annoyed her when they used it to talk about her behind her back.

She added dryly, "Tell Rainzi I’ve changed my mind."

Yann smiled, clearly delighted, and then his icon was instantly replaced by Rainzi’s. Fair enough: with the countdown proceeding, the Mimosans had better things to do than fake inertia for its own sake.

Rainzi’s response was more cautious than Yann’s. "Are you certain you want to do this? After everything you told me?"

"I’m the quintessential singleton," Cass replied. "I weigh up all my choices very carefully."