Satoshi Murakawa

Surface Majorana cone of the superfluid 3He B phase

The superfluid 3 He B phase, one of the oldest unconventional fermionic condensates experimentally realized, is recently predicted to support Majorana fermion surface states. Majorana fermion, which is characterized by the equivalence of particle and antiparticle, has a linear dispersion relation referred to as the Majorana cone. We measured the transverse acoustic impedance Z of the superfluid 3 He B phase changing its boundary condition and found a growth of peak in Z on a higher specularity wall. Our theoretical analysis indicates that the variation of Z is induced by the formation of the cone-like dispersion relation and thus confirms the important feature of the Majorana fermion in the specular limit.

Odd-frequency Cooper pairs and zero-energy surface bound states in superfluid 3He

He. The odd-frequency pair amplitude is closely related to the local density of states in the low energy limit. Wederive a formula relating explicitly the two quantities. This formula holds for arbitrary boundarycondition at the surface. We also present some numerical results on the surface odd-frequency pairamplitude in superfluid

Resonant Frequency Change of Torsional Oscillator Induced by Solid 4He in Torsion Rod

The contribution of solid 4He contained in the torsion rod of a torsional oscillator to its resonant frequency is investigated using a modified torsional oscillator. The purpose of the present study is to discriminate between two possible contributions to the resonant frequency of the torsional oscillator, which abruptly increases below ∼0.2 K. The first possible contribution is the elastic property change of solid 4He in the torsion rod (i.e., shear modulus increase), and the second possible contribution is mass decoupling by the supersolid transition of solid 4He in the oscillating body (i.e., a decrease in the momentum inertia). A torsional oscillator that has no hollow space for solid 4He in the body was constructed, and its resonant frequency and Q-factor were compared to those of the conventional oscillator. The shear modulus contributions of solid 4He in the torsion rod were identical, but the momentum inertias of solid 4He in the oscillating body were quite different between the two oscillators. S...

Effect of Rotation on Elastic Moduli of Solid

We report measurements of elastic moduli of hcp solid

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He

He down to 15 mK when the samples are rotated unidirectionally. Recent investigations have revealed that the elastic behavior of solid

Transverse Acoustic Impedance of Superfluid 3 He B Phase in Weak Magnetic Fields

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Surface condition dependence of transverse acoustic impedance in superfluid 3He

He is dominated by gliding of dislocations and pinning of them by

Transverse acoustic impedance of normal liquid 3He with 4He coating

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New Anomaly in the Transverse Acoustic Impedance of Superfluid 3He-B with a Wall Coated by Several Layers of 4He

He impurities, which move in the solid like Bloch waves (impuritons). Motivated by the recent controversy of torsional oscillator studies, we have preformed direct measurements of shear and Youngs moduli of annular solid