D17 Quantum Cosmology: Search for Primordial Gravitational Waves

Topic

Central to this model are next-generation experiments—one a satellite-based mission surveying the entire sky, the other a network of ground-based cryogenic telescopes—designed to measure the polarization of the cosmic microwave background with sufficient sensitivity to conclusively detect, or entirely rule out, the signal of primordial gravitational waves from inflation; they achieve this by deploying a vast number of superconducting detectors across many distinct frequency bands.

Both experiments require techniques to first eliminate a contaminating signal caused by ordinary gravitational lensing before they can access the much weaker inflationary signal itself, which lies beneath that contamination.

The satellite experiment’s most notable feature is its continuous, all-sky observation across multiple simultaneous frequency bands, allowing for the clean separation of the cosmic signal from dust within our own galaxy and from synchrotron emission; this is crucial because the target signal is far weaker than the ordinary polarization of the cosmic background itself, and at low frequencies, galactic dust produces a polarization pattern that can easily be mistaken for it. The availability of numerous distinct bands enables the separate modeling and subtraction of various foreground components, thereby revealing the primordial signal—if it exists at that level of sensitivity—while ensuring that, should it fail to appear even at that sensitivity, entire families of inflationary models would be definitively ruled out. Thus, from the next-generation experiments that open this document to the potential definitive exclusion that concludes it—encompassing the removal of gravitational lensing contamination and the separation of the cosmic signal from galactic dust—quantum cosmology demonstrates how a single search, conducted with sufficient sensitivity, can ultimately confirm or rule out an entire family of theories regarding the origin of the universe once and for all.

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