Yasumasa Tsutsumi

Field-Angle-Dependent Specific Heat Measurements and Gap Determination of a Heavy Fermion Superconductor URU2Si2

To identify the superconducting gap structure in URu2Si2, we perform field-angle-dependent specific heat measurements for the two principal orientations in addition to field rotations, and a theoretical analysis based on microscopic calculations. The Sommerfeld coefficient gamma(H)s in the mixed state exhibit a distinctly different field dependence. This comes from point nodes and the substantial Pauli paramagnetic effect of URu2Si2. These two features combined give rise to a consistent picture of superconducting properties, including a possible first order transition of Hc2 at low temperatures.

Twofold spontaneous symmetry breaking in the heavy-fermion superconductor UPt3.

The field-orientation dependent thermal conductivity of the heavy-fermion superconductor UPt3 was measured down to very low temperatures and under magnetic fields throughout the distinct superconducting phases: B and C phases. In the C phase, a striking twofold oscillation of the thermal conductivity within the basal plane is resolved reflecting the superconducting gap structure with a line of node along the a axis. Moreover, we find an abrupt vanishing of the oscillation across a transition to the B phase, as a clear indication of a change of gap symmetries. We also identify extra two line nodes below and above the equator in both B and C phases. From these results together with the symmetry consideration, the gap function of UPt3 is determined as a E(1u) representation characterized by a combination of two line nodes at the tropics and point nodes at the poles.

Symmetry-Protected Topological Superfluids and Superconductors —From the Basics to 3He—

In this article, we give a comprehensive review of recent progress in research on symmetry-protected topological superfluids and topological crystalline superconductors, and their physical consequences such as helical and chiral Majorana fermions. We start this review article with the minimal model that captures the essence of such topological materials. The central part of this article is devoted to the superfluid

Majorana surface states of superfluid He3 A and B phases in a slab

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Chiral Symmetry Breaking in Superfluid 3He-A

He, which serves as a rich repository of novel topological quantum phenomena originating from the intertwining of symmetries and topologies. In particular, it is emphasized that the quantum fluid confined to nanofabricated geometries possesses multiple superfluid phases composed of the symmetry-protected topological superfluid B-phase, the A-phase as a Weyl superfluid, the nodal planar and polar phases, and the crystalline ordered stripe phase. All these phases generate noteworthy topological phenomena, including topological phase transitions concomitant with spontaneous symmetry breaking, Majorana fermions, Weyl superfluidity, emergent supersymmetry, spontaneous edge mass and spin currents, topological Fermi arcs, and exotic quasiparticles bound to topological defects. In relation to the mass current carried by gapless edge states, we also briefly review a longstanding issue on the intrinsic angular momentum paradox in

Symmetry protected topological superfluid 3He-B

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A Spin Triplet Superconductor UPt3

He-A. Moreover, we share the current status of our knowledge on the topological aspects of unconventional superconductors, such as the heavy-fermion superconductor UPt

UPt3as a topological crystalline superconductor

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Edge Current due to Majorana Fermions in Superfluid 3He A- and B-Phases

and superconducting doped topological insulators, in connection with the superfluid

Stability of a half-quantum vortex in rotating superfluid He 3 − A between parallel plates

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