- Scientists are developing an experiment to test whether gravity is quantum
- In quantum mechanics, which describes the behavior of atoms and molecules – objects behave differently from what we know: they can exist in a quantum superposition of being in two places at the same time.
- Now, scientists are looking for a way to determine if gravity works this way by blowing up micro-diamonds in a vacuum.
- If gravity were quantum, it would 'burn' the diamond – a fascinating phenomenon that strongly binds two objects together in a way impossible in everyday life.
- This research will help drive understanding of black holes, the big bangand the universe
The Quantum Gravity Experiment
Scientists are developing an experiment to test whether gravity is quantum – one of the most profound questions about our universe.
General relativity and quantum mechanics are the two most fundamental descriptions of nature we have. General relativity explains gravity on large scales while quantum mechanics explains the behavior of atoms and molecules.
The challenge of unified theory
Arguably the most important unsolved problem in fundamental physics is the correct way to combine these two theories—determining whether gravity works at the quantum level. Although theoretical work has suggested many possibilities, experiments are needed to fully understand the behavior of gravity.
Revolutionary Test by Global Consortium
For a hundred years, experiments on the quantum nature of gravity seemed out of reach, but now scientists based at Warwick, UCL, Yale (USA), Northwestern (USA) and Groningen (Holland) will work together to investigate the problem. .
Their new idea is to evacuate two microdiamonds in a vacuum and put each in a quantum superposition of being in two places at the same time. This counterintuitive behavior is a fundamental feature of quantum mechanics.
Professor Morley's insight into the exam
Each diamond can be thought of as a smaller version of Schrödinger's cat. Principal Investigator Professor Gavin Morley, Department of Physics, University of Warwick, explains: “Schrödinger's Cat is a thought experiment that suggests that it would be really strange if everyday objects (and pets!) could exist in a quantum superposition of being in two places at once. We want to test the limits of this idea.
“Atoms and molecules have been successfully placed in such a superposition state, but we want to do this with much larger objects. Our diamond is made of a billion or more atoms. To test the quantum nature of gravity, we look for interactions between two such diamonds due to gravity. will do
“If gravity were quantum, it would be able to entangle two diamonds. Entanglement is a unique quantum effect where two objects are more strongly connected than is possible in our everyday lives. For example, if two coins could be entangled, you would see that whenever you Flip them over, they both land the same, even if it is not possible to know in advance whether they will be both heads or both tails.”
Challenges and implications
There are still many challenges to realizing this concept, which the team will investigate during the project. “For example, we have to eliminate all interactions between nanoparticles other than gravity, which is incredibly challenging because gravity is so weak,” said Dr. David Moore, Yale University.
Professor Morley, who is founding director of Warwick Quantum, a new interdisciplinary initiative for quantum technology research, added: “For me, the most important problem in physics at the moment is to develop an experiment that can test the quantum nature of gravity. This new project is our first step in this direction. An acceleration of the exciting journey.
Perspectives from allied scientists
Professor Sougato Bose, UCL, commented “It is difficult to overstate how significant this will be for experimental physicists who can find the right way to combine quantum mechanics and general relativity. People working on quantum gravity theory, such as string theory, are generally at high energies, Focuses on what happens in the vicinity of black holes and in the Big Bang.
“In contrast, our work is in the low-energy regime here on Earth, but will also provide invaluable information about it whether Gravity is quantum. Also, the experiment can be regarded as a verification of the generic predictions of any quantum theory of gravity at low energies.”
“By understanding the nature of gravity, we may be able to probe other aspects of fundamental physics, such as short-range exotic deviations from Newtonian gravity,” added Professor Anupam Majumder of the University of Groningen.
“This is a challenging experiment, and this project is a pathfinder in addressing some of the key technical challenges in making these experiments of the quantum aspects of gravity a reality,” said Andrew Gerasi, associate professor of physics. Northwestern University.
The project is called 'MAST-QG: macroscopic superposition towards witnessing the quantum nature of gravity'.