141 citations · 697 across the 29 of their papers we have counts for
29 papers
Magnonic Josephson junctions and synchronized precession
Kouki Nakata, Ji Zou, Jelena Klinovaja +1
There has been a growing interest in non-Hermitian physics. One of its main goals is to engineer dissipation and to explore ensuing functionality. In magnonics, the effect of dissi…
Non-Hermitian Casimir effect of magnons
Kouki Nakata, Kei Suzuki
There has been a growing interest in non-Hermitian quantum mechanics. The key concepts of quantum mechanics are quantum fluctuations. Quantum fluctuations of quantum fields confine…
Magnon dynamics in a Skyrmion-textured domain wall of antiferromagnets
Seungho Lee, Kouki Nakata, Oleg Tchernyshyov +1
We theoretically investigate the interaction between magnons and a Skyrmion-textured domain wall in a two-dimensional antiferromagnet and elucidate the resultant properties of magn…
Violation of the magnonic Wiedemann-Franz law in the strong nonlinear regime
Kouki Nakata, Yuichi Ohnuma, Se Kwon Kim
The celebrated Wiedemann-Franz (WF) law which governs the relation between charge and heat transport traces back to the experimental discovery in 1853 by Wiedemann and Franz. Despi…
Direct and alternating magnon spin currents across a junction interface irradiated by linearly polarized laser
Kouki Nakata, Yuichi Ohnuma
The developments in the field of quantum optics raise expectations that laser-matter coupling is a promising building block for magnonics. Here, we propose a method for the generat…
Magnonic Casimir Effect in Ferrimagnets
Kouki Nakata, Kei Suzuki
Quantum fluctuations are the key concepts of quantum mechanics. Quantum fluctuations of quantum fields induce a zero-point energy shift under spatial boundary conditions. This quan…
Optomagnonic Josephson effect in antiferromagnets
Kouki Nakata
Combining advanced technologies of optics and antiferromagnetic spintronics, we present a method to realize ultrafast spin transport. The optical Barnett effect provokes quasiequil…
Magnonic thermal transport using the quantum Boltzmann equation
Kouki Nakata, Yuichi Ohnuma
We present a formula for thermal transport in the bulk of Bose systems based on the quantum Boltzmann equation (QBE). First, starting from the quantum kinetic equation and using th…
Optomagnonic Barnett effect
Kouki Nakata, Shintaro Takayoshi
Combining the technologies of quantum optics and magnonics, we find that the circularly polarized laser can dynamically realize the quasiequilibrium magnon Bose-Einstein condensate…
Laser control of magnonic topological phases in antiferromagnets
Kouki Nakata, Se Kwon Kim, Shintaro Takayoshi
We study the laser control of magnon topological phases induced by the Aharonov-Casher effect in insulating antiferromagnets (AFs). Since the laser electric field can be considered…
Universal -suppression of magnonic shot noise in diffusive insulating magnets
Kouki Nakata, Yuichi Ohnuma, Mamoru Matsuo
Extending a Boltzmann-Langevin theory to magnons, we show a universality of current-noise suppression in diffusive systems against the difference of quantum-statistical properties…
Asymmetric quantum shot noise in magnon transport
Kouki Nakata, Yuichi Ohnuma, Mamoru Matsuo
We study a frequency-dependent noise-to-current ratio for asymmetric, symmetric, and noncommutative current-noise in a ferromagnetic insulating junction, and extract quantum-mechan…
Tunable Magnonic Thermal Hall Effect in Skyrmion Crystal Phases of Ferrimagnets
Se Kwon Kim, Kouki Nakata, Daniel Loss +1
We theoretically study the thermal Hall effect by magnons in skyrmion crystal phases of ferrimagnets in the vicinity of the angular momentum compensation point (CP). To this end, w…
Magnonic Noise and Wiedemann-Franz Law
Kouki Nakata, Yuichi Ohnuma, Mamoru Matsuo
We theoretically establish mutual relations among magnetic momentum, heat, and fluctuations of propagating magnons in a ferromagnetic insulating junction in terms of noise and the…
Magnonic topological insulators in antiferromagnets
Kouki Nakata, Se Kwon Kim, Jelena Klinovaja +1
Extending the notion of symmetry protected topological phases to insulating antiferromagnets (AFs) described in terms of opposite magnetic dipole moments associated with the magnet…
Magnonic quantum Hall effect and Wiedemann-Franz law
Kouki Nakata, Jelena Klinovaja, Daniel Loss
We present a quantum Hall effect of magnons in two-dimensional clean insulating magnets at finite temperature. Through the Aharonov-Casher effect, a magnon moving in an electric fi…
Spin Currents and Magnon Dynamics in Insulating Magnets
Kouki Nakata, Pascal Simon, Daniel Loss
Nambu-Goldstone theorem provides gapless modes to both relativistic and nonrelativistic systems. The Nambu-Goldstone bosons in insulating magnets are called magnons or spin-waves a…
Wiedemann-Franz Law for Magnon Transport
Kouki Nakata, Pascal Simon, Daniel Loss
One of the main goals of spintronics is to improve transport of information carriers and to achieve new functionalities with ultra-low dissipation. A most promising strategy for th…
Magnon transport through microwave pumping
Kouki Nakata, Pascal Simon, Daniel Loss
We present a microscopic theory of magnon transport in ferromagnetic insulators (FIs). Using magnon injection through microwave pumping, we propose a way to generate magnon dc curr…
Josephson and Persistent Spin Currents in Bose-Einstein Condensates of Magnons
Kouki Nakata, Kevin A. van Hoogdalem, Pascal Simon +1
Using the Aharonov-Casher (A-C) phase, we present a microscopic theory of the Josephson and persistent spin currents in quasi-equilibrium Bose-Einstein condensates (BECs) of magnon…
Bose-Einstein condensation of magnons in spin pumping systems
Kouki Nakata, Yusuke Korai
We clarify the condition for the occurrence of magnon Bose-Einstein condensation (BEC) in spin pumping systems without using external pumping magnetic fields. The Goldstone model i…
The temperature dependence of quantum spin pumping generated using electron spin resonance with three-magnon splittings
Kouki Nakata
On the basis of the Schwinger-Keldysh formalism, we have closely investigated the temperature dependence of quantum spin pumping by electron spin resonance. We have clarified that…
Thermal spin pumping mediated by magnon in the semiclassical regime
Kouki Nakata
We microscopically analyze thermal spin pumping mediated by magnons, at the interface between a ferromagnetic insulator and a non-magnetic metal, in the semiclassical regime. The g…
A short note on spin pumping theory with Landau-Lifshitz-Gilbert equation under quantum fluctuation; necessity for quantization of localized spin
Kouki Nakata
We would like to point out the blind spots of the approach combining the spin pumping theory proposed by Tserkovnyak et al. with the Landau-Lifshitz-Gilbert equation; this method h…