An unsolved mystery of quantum mechanics

Last night I saw … I know not what or who.
Pale twins, they stretched along the ground,
alive or dead – or even both at once.

They came from nowhere, silent, colourless.
A single wavelength, monochrome, rising
from darkness into ghostly light, they grew

and swelled, hoping for someone who might determine
their identity, know something of their substance,
give them a name – which is to say a home; or must they

stay unclaimed for ever, not known, not understood?
It's a mystery: like the way two slits in parallel allow
light waves, or particles, or single atoms at a time

to pass and make their marks in points of light
and though different, the outcome will be the same:
an interference pattern on a screen.

So even atoms can acknowledge kinship,
but these have none – just the tails of two cats
born of dark and fighting for their lives.