Anyone with a high school diploma knows Newton’s universal law of gravitation: according to this law, the gravitational force is inversely proportional to the square of the distance separating the mass from the gravitational mass. Nowadays, almost everyone has also heard about quantum mechanics thanks to the advent of quantum computing, which even the Prime Minister of Canada is able to understand.Explain.
A remarkable behavior of quantum systems is their ability to allow an object to assume two (if not more) states simultaneously. Thus, a particle with a positive rest mass (“massive particle”) can end up in two places at once. This isn’t science fiction: in fact, atomic interferometers regularly arrange cesium or rubidium atoms into configurations such that the quantum state of the atom Divide and present in two placesThese two places could be separated from each other by up to several centimeters.
These states are very sensitive to gravity, resulting in the most accurate measurement that scientists have been able to form the Earth’s gravitational field, which corresponds to 1/1015 For example. But the question is: what gravitational field does a massive particle create in such a quantum state?
To answer this question, particle physicists from the University of Montreal said Richard Mackenzie And Manu Paranjab They have been working since 2012 with their colleague Urjit Yajnikfrom the Indian Institute of Technology Bombay, India, with a scholarship from Quebec and Maharashtra Cooperation Awarded by the Ministry of International Relations and La Francophonie of Quebec.
Together with many other students and collaborators, they have produced a large body of papers in theoretical particle physics, and their latest monograph, which has just been published in Physical review lettersThe Journal of the American Physical Society, asks this question: What is the gravitational field of mass in a nonlocal spatial quantum superposition? Their surprising discovery is as follows: while it wouldn’t let it be known that a massive particle splits and is in two places at the same time, the gravitational field appears to come from only one place, given the average-mass location. particle.
To reach this conclusion, the team looked at scattering experiments conducted by particle physicists, such as in Large Hadron ColliderExperiments that aim to look inside atoms, nuclei, and other subatomic particles. Experiences Inelastic deep dispersion Carried out at the end of the 70s of the last century, it also proved the existence of quarks in the nucleus and confirmed the theory of strong interaction, or quantum chromodynamics.
Manu Paranjab
Credit: image courtesy
“It seemed obvious to us that we had to calculate the gravitational scattering behavior of other particles compared to the spatial nonlocal massive particles,” says Manu Paranjape. This calculation will make it possible to investigate the nature of the gravitational field created by the nonlocal massive particles. In doing so, we have demonstrated very clearly that scattering behaves As if the massive particle was in its intermediate position and not as if there were half a particle in each of two spatially distinct positions. In truth, this result was somewhat unexpected.”
Now comes the arduous stage of work, which is the empirical verification of the scientists’ theoretical calculations.
Richard Mackenzie
Credit: image courtesy
“Currently, the gravitational field of a particular atom is too weak to be observed experimentally, even with the most sensitive gravitational field detectors, the atomic interferometers,” notes Richard Mackenzie. However, it is possible to measure the gravitational field of a group of about a billion atoms.
Although it represents much less than a microgram of matter, this number of atoms is roughly equivalent to the number that interferes with the quantum state on the macroscopic level corresponding to what one considers Bose-Einstein condenser. It would be possible to form a non-local spatial superposition of a Bose-Einstein condensate of this size, which would allow the creation of measurable gravitational fields.
If the scientists’ theory can be experimentally verified, “the results will be amazing,” says Manu Paranjab. So we invite you to stay up to date with this question… wherever you are.
about this study
The article “What is the gravitational field of a mass in a nonlocal quantum-spatial superposition?” , By Orgit Yagnik and colleagues, Kan published On March 7, 2023 Physical review letters.
