Chemical potential of an antiferromagnetic magnon gas

Abstract

Understanding the statistics of quasi-particle excitations in magnetic systems is essential for exploring new magnetic phases and collective quantum phenomena. While the chemical potential of a ferromagnetic gas has been extensively investigated both theoretically and experimentally, its antiferromagnetic counterpart remains uncharted. Here, we derive the statistics of a two-component U(1)-symmetric Bose gas and apply our results to an axially-symmetric antiferromagnetic insulator. We find that the two magnon eigenmodes of the system are described by an equal and opposite chemical potential, in analogy with a particle-antiparticle pair. Furthermore, we derive the thermomagnonic torques describing the interaction between the coherent and incoherent antiferromagnetic spin dynamics. Our results show that the magnitude and sign of the chemical potential can be tuned via an AC magnetic field driving resonantly one of the magnon modes. Finally, we propose NV-center relaxometry as a method to experimentally test our predictions.

References in corpus (5)

• Probing condensed matter physics with magnetometry based on nitrogen-vacancy centres in diamond
• Electrically controlled long-distance spin transport through an antiferromagnetic insulator
• Experimental Signatures of Spin Superfluid Ground State in Canted Antiferromagnet Cr2O3 via Nonlocal Spin Transport
• Quantum-impurity relaxometry of magnetization dynamics
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• Exceptional sign changes of the non-local spin Seebeck effect in antiferromagnetic hematite
• Non-local spin Seebeck effect in the bulk easy-plane antiferromagnet NiO
• Thermal squeezing and nonlinear spectral shift of magnons in antiferromagnetic insulators
• Magnonics in collinear magnetic insulating systems
• Quantum-impurity sensing of altermagnetic order
• Thickness-dependent magnon spin transport in antiferromagnetic insulators: Crossover from quasi-three-dimensional to quasi-two-dimensional regimes