Question

The following pop science video discusses the experimental difficulty of measuring "quanta" of gravity. It seems to me that a significant argument involves how it would be difficult to investigate fluctuations of gravity on the plank scale, requiring detection methods that have densities that would collapse as a black hole.

In optics, one way of "seeing" a photon is by interfering it with using homodyne detection to interfere it with a strong signal. The strong signal essentially magnifies the signal, allowing it to be seen by detectors that are much less sensitive than single photon level.

Could such a scheme be used to measure gravitons? For example, if strong gravitational waves can be detected by LIGO, shouldn't a sufficiently strong wave already be measuring the "amplitude" statistics of the graviton? Similar to how a local oscillator (in a balanced homodyne detector) measures the shot noise (amplitude statistics) of the vacuum.

I suppose the issue is that this needs to be a particuarly strong wave signal so be above experimental noise?

Answer 1

LIGO is one tool being used to search for gravitational waves and the graviton. Gravitational waves are detected by measuring the shift in the relative positions of two masses caused by the waves. While LIGO has not directly detected the graviton, the presence of a gravitational wave would suggest its existence.

Step-by-step explanation:

The search for gravitational waves and the detection of the graviton have been ongoing challenges for scientists. LIGO (Laser Interferometer Gravitational-Wave Observatory) is one tool being used to search for gravitational waves. The detectors at LIGO are designed to measure the slight shift in the relative positions of two masses caused by gravitational waves. While LIGO has not directly detected the graviton, the presence of a gravitational wave would suggest the existence of the graviton according to wave-particle duality.