Anomalous tunneling transport of spin and heat by magnonic criticality

ORAL

Abstract

We present thermomagnetic transport in an ultracold atomic system with two ferromagnets linked via a magnetic quantum point contact [1]. Using the nonequilibrium field theory in the Schwinger-Keldysh formalism, we show a divergence in spin conductance and a slowing down of spin relaxation that manifest in the weak effective-Zeeman-field limit. These anomalous spin dynamics result from the magnonic critical point at which magnons become gapless due to spontaneous magnetization. Our findings unveil untapped dynamics in ultracold atomic systems, opening new avenues in thermomagnetism.

*We acknowledge JSPS KAKENHI for Grants (No. JP19J01006, No. JP20H01863, No. JP21H04565, No. JP21H01800, No. JP21K03436, No. JP22H01158, No. JP22K13981, No. JP23H01839, and No. JP24H00322) from MEXT, Japan, Pioneering Program of RIKEN for Evolution of Matter in the Universe (r-EMU), the RIKEN TRIP initia- tive (RIKEN Quantum), and by JST ERATO Grant No. JPMJER2302, Japan, JST PRESTO (JPMJPR2351) Matsuo Foundation, the National Natural Science Foundation of China (NSFC) under Grant No. 12374126, and the Priority Program of the Chinese Academy of Sciences, Grant No. XDB28000000.

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Publication: [1] Y. Sekino, Y. Ominato, H. Tajima, S. Uchino, and M. Matsuo, Thermomagnetic Anomalies by Magnonic Criticality in Ultracold Atomic Transport, Phys. Rev. Lett. 133, 163402 (2024)

Presenters

  • Yuta Sekino

    • RIKEN

Authors

  • Yuta Sekino

    • RIKEN

  • Yuya Omitano

    • Waseda University

  • Hiroyuki Tajima

    • The University of Tokyo

  • Shun Uchino

    • Waseda University

  • Mamoru Matsuo

    • University of Chinese Academy of Sciences