A PART of the results obtained from Monash University Malaysia students’ final-year projects under the supervision of Associate Professor Lan Boon Leong from the Engineering School has led to groundbreaking discovery in quantum physics.
It is conventionally thought that the predictions of the non-relativistic and relativistic versions of quantum theory are always close for the motion of a microscopic system at low speed.
Lan and two Electrical and Computer
Systems Engineering students ― Mehdi Pourzand and Chu Rui Jian ― in a paper recently published in the journal Results in Physics, however, wrote that this expectation was proven to be not true in general.
They said the two predictions will eventually disagree and the breakdown of agreement could happen quickly. They also showed the different predictions could be tested experimentally for the simplest atom ― hydrogen.
The standard practice to study the dynamics of quantum systems in the nonrelativistic regime is to use non-relativistic quantum theory, instead of the more complicated relativistic version. This is because the former is conventionally thought to yield similar results to the latter.
Lan said the surprising discovery at Monash had two important implications.
“To study the motion of a microscopic system at low speed, the standard scientific practice is to use non-relativistic quantum theory, which is mathematically and computationally less complicated than the relativistic version.
“Our finding implies that the relativistic theory must be used instead to correctly predict the motion after the agreement between the two theories breaks down.”
Lan added that this paradigm shift opens a new avenue of research in a wide range of fields; from atomic to molecular, chemical and condensed-matter physics, which could lead to new fundamental understandings and discoveries.
“Our finding also suggests some of the numerous studies, which utilised non-relativistic quantum theory, in the past are not entirely correct.
“For example, the puzzling discrepancies between the non-relativistic quantum predictions and experimental measurements for the simplest chemical reaction like the collision between hydrogen atom and deuterium molecule might be resolved by using relativistic quantum theory,” he added.
Lan said that after Mehdi returned to his home country, both of them continued to work on the project for about a year to obtain the rest of the results.
“The students’ achievements are all the more remarkable since they were not physics students. They only had rudimentary knowledge of quantum theory initially, since it is not a main part of the curriculum, but they were able to learn the essential parts of the theory quickly on their own.”
Mehdi said the project was very challenging but he enjoyed it tremendously.
“It is not common to have the opportunity to engage in a serious scientific research at the undergraduate level. I’m very happy that our group effort led to an important discovery,” he said.
“I have learned a lot about how to conduct research. But the most valuable thing I have learned is that we should always question conventional wisdom,” said Chu.
The two Monash graduates continue to pursue their passion in research.
Mehdi is applying to do a masters in physics in Canada, while Chu has moved on to doing his PhD in signal and image processing in France.
Both are still collaborating with Lan to extend their initial study.