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checking everything to her own satisfaction. "Okay. So why does that have to
break down? Why can t we just keep being blue-shifted?"
Vikram zoomed in on the diagram. "All phase shifts ultimately come from
interactions
intersections of one world line with another. In the Kumar model, every
network of world lines has a finite weave. At each intersection, there s a
tiny phase shift that makes time jump by about ten-to-the-minus-forty-three
seconds . . .
and it s meaningless to talk about either a smaller phase shift, or a shorter
time scale. So if you try to blue-shift a wave indefinitely, eventually you
reach a point where the whole system no longer has the resolution to keep
reproducing it." As the wave packet spiraled in, it began to take on a
smeared, jagged approximation of its former shape. Then it disintegrated into
unrecognizable noise.
Cordelia examined the diagram carefully, tracing individual components through
the final stages of the process. Finally she said, "How long before we see
evidence of this? Assuming the model s correct?"
Vikram didn t reply; he seemed to be having second thoughts about the wisdom
of the whole demonstration.
Gisela said, "In about two hours we should be able to detect quantized phase
in the experimental beams. And then we ll have another hour or so before "
Vikram glanced meaningfully at her privately, but Cordelia must have guessed
why the sentence trailed off, because she turned on him.
"What do you think I m going to do?" she demanded indignantly. "Collapse into
hysterics at the first glimmering of mortality?"
Vikram looked stung. Gisela said, "Be fair. We ve only known you three days.
We don t know what to expect."
"No." Cordelia gazed up at the stylized image of the beam that encoded them,
swarming now with everything from photons to the heaviest mesons. "But I m not
going to ruin the Dive for you. If I d wanted to brood about death, I would
have stayed home and read bad flesher poetry."
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Asimov's - The Planck Dive
She smiled. "Baudelaire can screw himself. I m here for the physics."
Everyone gathered round a single window as the moment of truth for the Kumar
model approached. The data it displayed came from what was essentially a
two-slit interference experiment, complicated by the need to perform it
without anything resembling solid matter. A
sinusoidal pattern showed the numbers of particles detected across a region
where an electron beam recombined with itself after traveling two different
paths;
since there were only a finite number of detection sites, and each count had
to be an integer, the pattern was already "quantized," but the analysis
software took this into account, and the numbers were large enough for the
image to appear smooth. At a certain wavelength, any genuine Planck scale
effects would rise above these artifacts, and once they appeared they d only
grow stronger.
The software said, "Found something!" and zoomed in to show a slight
staircasing of the curve. At first it was so subtle that Gisela had to take
the program s word that it wasn t merely showing them the usual, unavoidable
jagging. Then the tiny steps visibly broadened, from two horizontal pixels to
three. Sets of three adjacent detection sites, which moments ago had been
registering different particle counts, were now returning identical results.
The whole apparatus had shrunk to the point where the electrons couldn t tell
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that the path lengths involved were different.
Gisela felt a rush of pure delight, then an aftertaste of fear. They were
reaching down to brush their fingertips across the weave of the vacuum. It was
a triumph that they d survived this far, but their descent was almost
certainly unstoppable.
The steps grew wider; the image zoomed out to show more of the curve. Vikram
and Tiet cried out simultaneously, a moment before the analysis software
satisfied itself with rigorous statistical tests. Vikram repeated softly,
"That s wrong." Tiet nodded, and spoke to the software. "Show us a single
wave s phase structure." The display changed to a linear staircase. It was
impossible to measure the changing phase of a single wave directly, but
assuming that the two versions of the
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Asimov's - The Planck Dive beam were undergoing identical changes, this was
the progression implied by the interference pattern.
Tiet said, "This is not in agreement with the Kumar model. The phase is
quantized, but the steps aren t equal or even random, like the Santini model.
They re structured across the wave, in cycles. Narrower, broader, narrower
again . . ."
Silence descended. Gisela gazed at the pattern and struggled to concentrate,
elated that they d found something unexpected, terrified that they might fail
to make sense of it. Why wouldn t the phase shift come in equal units? This
cyclic pattern was a violation of symmetry, allowing you to pick the phase
with the smallest quantum step as a kind of fixed reference point an idea that
quantum mechanics had always declared to be as meaningless as singling out one
direction in empty space.
But the rotational symmetry of space wasn t perfect: in small enough networks,
the usual guarantee that all directions would look the same no longer held up.
Was that the answer?
The angles the two beams had to take to reach the detector were themselves
quantized, and that effect was superimposed on the phase?
No. The scale was all wrong. The experiment was still taking place over too
large a region.
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