Researchers claim to have derived particles obeying the theory of relativity from a quantum system in a paper published in the journal Science. If correct, it would provide a promising approach towards a Grand Unified Theory. But according to a Nobel Laureate, the claim is 鈥渂asically untrue鈥�.
A Grand Unified Theory is the greatest goal of physics and would unify the four fundamental forces of nature; electromagnetism, the strong and weak nuclear forces and gravity. But the theory of quantum mechanics, which encompasses the first three forces, seems to be incompatible with general relativity, which describes gravity.
In the new work, Shou-Cheng Zhang and Jiangping Hu of Stanford University in California claim they have mathematically derived relativistic particles from a four dimensional Quantum Hall System. In the Quantum Hall Effect, electrons pair up to share quantum states and behave like a fluid.
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If Zhang and Hu were right, it would be the first example of mathematical consistency between quantum theory and relativity outside string theory. However, string theory involves not four but 11 dimensions, which some researchers find hard to accept.
Making waves
Although Zhang and Hu鈥檚 equations and mathematical derivation are sound, they have misinterpreted the meaning of terms in their equations says Bob Laughlin, also at Stanford, who shared the 1998 Nobel prize for Physics for solving the Quantum Hall effect in two dimensions. 鈥淲hen you examine the meaning of what they鈥檙e saying, it鈥檚 basically untrue,鈥� he says.
However, Zhang and Hu have now done what Laughlin himself could not 鈥� generalise his Quantum Hall effect solution to a four dimensional fluid. Laughlin acknowledges: 鈥淭his is a major breakthrough in theoretical physics鈥�.
But Zhang and Hu do not stop there. They go on to show that when waves moving in the four-dimensional fluid break the three-dimensional surface, they obey the same equations of motion as particles do in special and general relativity.
They claim some of these waves are gravitons, the quantum mechanical particles that mediate gravity. 鈥淪ome are gravitons and some are photons,鈥� says Hu.
But Laughlin says the waves are unstable and will dissolve into their component parts when they hit something. 鈥淭heir equations are true, but they鈥檙e just not applying to real particles,鈥� he says.
Interactive argument
Hu says this does not invalidate the claim of having derived relativity. 鈥淚nteractions are not included,鈥� he says.
But the very fact that they are not included is what makes it misleading to label the mathematical entities in the theory as particles, says Laughlin.
He believes more thorough refereeing before publication would have prevented the problem. 鈥淭hese problems should have been exposed,鈥� he told New 杏吧原创.
An editor at Science, Brooks Hanson, said: 鈥淭his paper is starting to address a fundamental question in physics.鈥� But no-one able to address Laughlin鈥檚 claim in detail was available for comment.
