Gravitons could bridge the divide between general relativity and quantum mechanics. But efforts to find these hypothetical particles have proved tricky — until now.
Subscribe to Seeker! http://bit.ly/subscribeseeker
Watch more Elements! http://bit.ly/ElementsPlaylist
Visit our shop at http://shop.seeker.com
The renowned physicist Freeman Dyson suggested that a hypothetical detector sensitive enough to observe a single graviton would be so massive that the detector itself would collapse into a black hole. But what if we’re going about this the wrong way? What if instead of trying to find just one graviton, we search for a telltale sign that only a group of them can create? That’s what three researchers proposed in a paper from October of 2020.
The physicists were inspired by Brownian motion, which describes how particles in a fluid bounce around randomly. If gravity really is carried by bosons, then maybe they move around randomly too, creating a sort of “noise” or fuzziness that existing gravitational wave detectors like LIGO can suss out.
Of course, the noise has to be pronounced enough for LIGO to notice. It’s a bit beyond the scope of this episode but just know that waves like light can come in different quantum states— in fact, LIGO uses light in a “squeezed” state for enhanced sensitivity The researchers calculated that gravitational waves in different quantum states would produce different amounts of noise.
How the Bits of Quantum Gravity Can Buzz https://www.quantamagazine.org/gravit… “New calculations show how hypothetical particles called gravitons would give rise to a special kind of noise.”
The Edge of Physics: Do Gravitons Really Exist? https://futurism.com/the-edge-of-phys… “In an attempt to marry gravity with quantum theory, physicists came up with a hypothetical particle—the graviton. The graviton is said to be a massless, stable, spin-2 particle that travels at the speed of light.”
Is Gravity Quantum? https://www.scientificamerican.com/ar… “To directly observe the minuscule effects a graviton would have on matter, physicist Freeman Dyson famously noted, a graviton detector would have to be so massive that it collapses on itself to form a black hole.”