Electromagnetic Response of a kx±ikyk_x\pm ik_y Superconductor: Effect of Order Parameter Collective Modes

Effects of order parameter collective modes on electromagnetic response are studied for a clean spin-triplet superconductor with $k_x\pm ik_y$ orbital symmetry, which has been proposed as a candidate pairing symmetry for Sr$_2$RuO$_4$. It is shown that the $k_x \pm ik_y$ superconductor has characteristic massive collective modes analogous to the clapping mode in the A-phase of superfluid $^3$He. We discuss the contribution from the collective modes to ultrasound attenuation and electromagnetic absorption. We show that in the electromagnetic absorption spectrum the clapping mode gives rise to a resonance peak well below the pair breaking frequency, while the ultrasound attenuation is hardly influenced by the collective excitations.Comment: 4 pages RevTex, 1 eps figur

Chiral Correction to the Spin Fluctuation Feedback in two-dimensional p-wave Superconductors

We consider the stability of the superconducting phase for spin-triplet p-wave pairing in a quasi-two-dimensional system. We show that in the absence of spin-orbit coupling there is a chiral contribution to spin fluctuation feedback which is related to spin quantum Hall effect in a chiral superconducting phase. We show that this mechanism supports the stability of a chiral p-wave state.Comment: 8 pages. The final version is accepted for publication in Europhys Let

Vortex with Fractional Quantum Numbers in Chiral p-Wave Superconductor

We show that a vortex in a chiral p-wave superconductor, which has the p_{x}+ i p_{y}-wave pairing state and breaks U(1), parity and time reversal symmetry simultaneously, has fractional charge -{n e}/{4} and fractional angular momentum -n^{2}/{16} (n; vorticity). This suggests that the vortex could be anyon and could obey fractional statistics. Electromagnetic property of the vortex is also discussed and we find that an electric field is induced near the vortex core.Comment: 10 pages, 3 figures, accepted for publication in Phys. Rev.

Axial Anomaly Effect in Chiral p-wave Superconductor

We analyze the chiral p-wave superconductor in the low temperature region. The superconductor has a epsilon_{x} p_{x} + i epsilon_{y} p_{y}-wave gap in two dimensional space (2D). Near the second superconducting transition point, the system could be described by a quasi-1D chiral p-wave model in 2D. The axial anomaly occurs in such a model and causes an accumulation of the quasiparticle in an inhomogeneous magnetic field. The effect is related to the winding number of the gap.Comment: 12 pages, 1 figure, RevTex. The final version is accepted for publication in J. Phys. Soc. Jp

Multiple Superconducting Phases in New Heavy Fermion Superconductor PrOs4Sb12

The superconducting gap structure of recently discovered heavy fermion superconductor PrOs4Sb12 was investigated by using thermal transport measurements in magnetic field rotated relative to the crystal axes. We demonstrate that a novel change in the symmetry of the superconducting gap function occurs deep inside the superconducting state, giving a clear indication of the presence of two distinct superconducting phases with twofold and fourfold symmetries. We infer that the gap functions in both phases have a point node singularity, in contrast to the familiar line node singularity observed in almost all unconventional superconductors.Comment: 4 Pages, 4 Figure

Numerical Renormalization Group Study of Kondo Effect in Unconventional Superconductors

Orbital degrees of freedom of a Cooper pair play an important role in the unconventional superconductivity. To elucidate the orbital effect in the Kondo problem, we investigated a single magnetic impurity coupled to Cooper pairs with a $p_x +i p_y$ ($d_{x^2-y^2}+id_{xy}$) symmetry using the numerical renormalization group method. It is found that the ground state is always a spin doublet. The analytical solution for the strong coupling limit explicitly shows that the orbital dynamics of the Cooper pair generates the spin 1/2 of the ground state.Comment: 4 pages, 2 figures, JPSJ.sty, to be published in J. Phys. Soc. Jpn. 70 (2001) No. 1

Differentiation of Infectious Bursal Disease Virus (IBDV) Strains in Experimentally Infected Chickens

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). Differentiation of IBDV strains is crucial for effective vaccination programs and epidemiological investigations. In this study, a combination of clinical, histopathological examinations, immunohistochemistry and indirect immunofluorescence techniques were used to differentiate different IBDV strains. Sixty three weeks old chickens were divided randomly into five equal groups. Chickens of four groups were inoculated orally with different strains of IBDV. Chickens of the fifth group were kept as a control. Three chickens per group were euthanized at 3, 7, 14, 21 days post-inoculation (dpi). Euthanized chickens subjected to autopsy and tissue samples were collected in 10% neutral-buffered formalin for histopathology, immunohistochimestry and immunoflrourescence. The results revealed that clinical examination and histopathology cannot be used alone for differentiation of IBDV strains, while immunohistochemical and immunofluorescence techniques are reliable tools for differentiation of IBDV strains

Quasiparticle spectrum of the hybrid s+g-wave superconductors YNi_2B_2C and LuNi_2B_2C

Recent experiments on single crystals of YNi$_2$B$_2$C have revealed the presence of point nodes in the superconducting energy gap Delta(k} at k = (1,0,0), (0,1,0), (-1,0,0), and (0,-1,0). In this paper we investigate the effects of impurity scattering on the quasiparticle spectrum in the vortex state of s+g-wave superconductors, which is found to be strongly modified in the presence of disorder. In particular, a gap in the quasiparticle energy spectrum is found to open even for infinitesimal impurity scattering, giving rise to exponentially activated thermodynamic response functions, such as the specific heat, the spin susceptibility, the superfluid density, and the nuclear spin lattice relaxation. Predictions derived from this study can be verified by measurements of the angular dependent magnetospecific heat and the magnetothermal conductivity.Comment: 8 pages, RevTex, 4 figure

Abelian Chern-Simons Term in Superfluid 3He-A

We show in this paper that Abelian Chern-Simons term is induced in 2+1 and 3+1 dimensional rotating superfluid $^{3}$He-A and plays important roles in its dynamics. Because U(1) symmetry is spontaneously broken in $^{3}$He-A, Goldstone mode appears and contributes to induced Chern-Simons term. We found that the coefficient of Chern-Simons term, which is equivalent to Hall conductance, depends on an infra-red cut off of the Goldstone mode, and that the orbital angular momentum of $^{3}$He-A in a cylinder geometry is derived from Chern-Simons term.Comment: 16 pages, 2 figures, LaTeX, minor points are changed, references are added. Accepted for publication in Physics Letters

Temporal Oscillation of Conductances in Quantum Hall Effect of Bloch Electrons

We study a nonadiabatic effect on the conductances in the quantum Hall effect of two-dimensional electrons with a periodic potential. We found that the Hall and longitudinal conductances oscillate in time with a very large frequencies due to quantum fluctuation.Comment: 8 pages, 4 figure