Pressure dependence of theA-Bphase transition temperature in superfluid3Hein 1.1-μm slab geometry

Study of Superfluid $$^3$$ 3 He Under Nanoscale Confinement

“…In the first such experiments both the superfluid density and the NMR response were investigated [15,16] for 300 nm spacing; the equilibrium state was found to be A phase at all pressures. Later NMR studies used thicker nominal spacings of 0.8 [17]and 1.1 µm [18]. In this case the film is expected to undergo an A to B phase transition, however the experimental evidence of the B phase and of this transition was unclear highlighting the importance of cavity thickness uniformity; we compare these results with our subsequent work in [6].…”

Symmetry protected topological superfluid3He-B

“…The surface roughness drastically changes the surface structure of order parameters and low-lying surface states in the superfluid 3 He-B [106,108,152,154]. The pair-breaking effect and the enhancement of the surface density of states due to the existence of the surface Andreev bound states have been observed in several experiments [109,110,271,112,113,114,115,116,117,118,155,156,157,158,159]. The contributions of surface Andreev bound states have also been detected through the deviation of the heat capacity from that in the bulk 3 He-B [160] as well as the anomalous attenuation of transverse sound wave [161].…”

“…At the weak coupling limit, the planar is energetically degenerate to the A-phase that is the time-reversal symmetry breaking phase with point nodes, while the strong coupling effect that is the spin-fluctuation feedback effect can stabilize the A-phase relative to the planar phase and the A-B phase boundary becomes the first order transition. The pair breaking effect and the enhancement of the surface density of states due to the surface bound state have been observed by several experiments, by using the NMR techniques [112,113,114,115,116,117,118,155,156,157], the motion of a vibrating wire resonator [158], transverse acoustic impedance [162,163,164,165,166,167,168,169], surface contributions of the heat capacity [160], and anomalous attenuation of transverse sound [161]. Among them, Murakawa et al [165,168] has observed the specularity dependence of the surface density of states by systematically controlling the surface specularity by coating the surface with 4 He layers.…”

“…In both the experiments, the magnetic field is applied along the plates. NMR techniques have been developed to reveal the phase diagram in a restricted geometry [112,113,114,115,116,117,118]. Most recently, Levitin et al [117,118] has succeeded in uncovering thê n-textures and the confinement-induced order parameter distortion in a thin slab wellcontrolled surface condition.…”

“…This indicates that the topological phase transition from the time-reversal invariant B-phase to time-reversal breaking Aphase occurs at the critical value of the "thickness" even at zero pressures. Several experiments have observed the confinement-induced A-B phase transition in a slab geometry with a thickness comparable to the superfluid coherence length [109,110,271,112,113,114,115,116,117,118]. We introduce in Sec.…”