Researchers at the Theoretical Physics Division of Nankai University have proposed a groundbreaking hypothesis on the spin vector potential and its verification through the spin Aharonov-Bohm (AB) effect. Led by Professor Jing-Ling Chen, along with his students Xing-Yan Fan and Xiang-Ru Xie at Nankai University, this study presents a novel approach to understanding the interactions between spins and electromagnetic potentials. The research is published in the journal Fundamental Research.

“The Aharonov-Bohm effect is a quintessential quantum phenomenon where a charged particle is influenced by an electromagnetic potential despite being in a field-free region. This underscores the significance of potentials in quantum physics,” explains Professor Chen. He further adds, “Our work extends this concept to spin, proposing a spin vector potential and demonstrating its effects through a thought experiment akin to the classic double-slit interference experiment.”

The team proposes the existence of a spin vector potential induced by a particle with spin, which can be observed through a double-slit experiment. This gedanken experiment would involve an electron passing through two slits, with a spin source placed behind them. The resulting interference pattern would differ from the conventional one, indicating the influence of the spin vector potential. This effect, termed the spin AB effect, mirrors the traditional magnetic AB effect but replaces the magnetic field with spin.

The hypothesis was developed by considering the angular momentum operator and deriving a spin vector potential mathematically. The team also explored the implications of this potential in explaining various spin interactions, including the Dzyaloshinsky-Moriya (DM) interaction and the dipole-dipole interaction. These interactions, which are fundamental in condensed matter physics, emerge naturally from the Dirac Hamiltonian when the spin vector potential is considered.

Professor Chen elaborates, “The DM interaction, which explains weak ferromagnetism in antiferromagnetic materials, and the dipole-dipole interaction can both be derived from the spin vector potential. This provides a unified framework for understanding these complex interactions.”

The study’s results suggest that the spin AB effect can be experimentally verified, opening new avenues for research in quantum mechanics and spintronics. “Observing the spin AB effect in a lab would not only confirm our hypothesis but also pave the way for new technological applications in quantum computing and information processing,” says Professor Chen.

The implications of this research are profound, as it offers a new perspective on the role of potentials in quantum mechanics. By introducing the concept of spin vector potential, the study bridges a gap between classical and quantum physics, highlighting the indispensable nature of potentials in the quantum realm.

In conclusion, the Professor Chen’s team’s work presents a significant advancement in our understanding of spin interactions and the fundamental principles of quantum mechanics. The experimental verification of the spin AB effect could lead to breakthroughs in various fields, including quantum information science and condensed matter physics.

Journal Reference

Chen, J.-L., Fan, X.-Y., & Xie, X.-R. (2024). Spin vector potential and spin Aharonov-Bohm effect. Fundamental Research. DOI: https://doi.org/10.1016/j.fmre.2023.10.003

About The Author

Jing-Ling Chen is a professor of physics at Nankai University. He got his bachelor’s degree (1994), master’s degree (1997) and doctor’s degree (2000) in Nankai University, P. R. China. He has been a post-doc at Beijing institute of apply physics (2000-2002) and a research fellow at National University of Singapore (2002-2005), respectively. His research interest is quantum physics and quantum information, especially in quantum fundamental problems, such as EPR paradox, quantum entanglement, EPR steering, Bell’s nonlocality and quantum contextuality. Due to his contribution in quantum foundations, he has won the Paul Ehrenfest Best Paper Award for Quantum Foundations (2021). Recently, he has made some original explorations on spin, such as proposing the spin vector potential, presenting the spin-type Aharonov-Bohm effect, and predicting the spin angular-momentum wave.