Signatures of hidden order symmetry in torque oscillations, elastic constant anomalies and field induced moments in URu2Si2

We discuss the conclusions on the symmetry of hidden order (HO) in URu2Si2 that may be drawn from recent torque experiments in rotating magnetic field by Okazaki et al. [1]. They are very sensitive to changes in the magnetic susceptibility induced by HO. We show that the observed twofold angular torque oscillations give evidence that hidden order has degenerate E- type (yz,zx) symmetry where both components are realised. The oscillations have the wrong characteristics or are absent for the 1D nontrivial representations like quadrupolar B1 (x^2-y^2) and B2 (xy) type HO or hexadecapolar A2(xy(x^2-y^2)) type HO. Therefore they may be excluded as candidates for hidden order. We also predict the field-angular variation of possible field-induced Bragg peaks based on underlying E-type order parameter and discuss the expected elastic constant anomalies.Comment: 11 pages, 1 figure ; to appear in Phys. Rev.

Derivation of the superconducting gap equation for the noncentrosymmetric superconductor Li2Pt3B

We present here the mathematical background of our approach, presented in Phys. Rev. B 86, 134526 (2012) regarding the gap function and symmetry for the noncentrosymmetric (NCS) superconductor $Li_2Pt_3B$. As revealed by the experiment, this NCS superconductor gives rise to line nodes in the superconducting order parameter, which is responsible for many of its experimental behaviors. Owing to the enhanced d-character of the relevant bands that cross the Fermi level,the system gets weakly correlated. The nature and symmetry of this nodal behavior is explained from a microscopic viewpoint. In this article starting with an Hubbard model relevant for this NCS system by considering the effect of the onsite Coulomb repulsion on the pairing potential perturbatively, we extract the superconducting gap equation. Further analysis of this equation predicts a $s_\pm$ wave gap function with line nodes as the most promising candidate in the superconducting state.Comment: 7 pages, Proceeding versio

A phase diagram for a topological Kondo insulating system

The discovery of topological insulators in non-interacting electron systems has motivated the community to search such topological states of matter in correlated electrons both theoretically and experimentally. In this paper we investigate a phase diagram for a topological Kondo insulating system, where an emergent "spin"-dependent Kondo effect gives rise to an inversion for heavy-fermion bands, responsible for a topological Kondo insulator. Resorting to the U(1) slave-boson mean-field analysis, we uncover an additional phase transition inside the Kondo insulating state in two dimensions, which results from the appearance of the topological Kondo insulator. On the other hand, we observe that the Kondo insulating state is distinguished into three insulating phases in three dimensions, identified with the weak topological Kondo insulator, the strong topological Kondo insulator, and the normal Kondo insulator, respectively, and classified by Z$_{2}$ topological indices. We discuss the possibility of novel quantum criticality between the fractionalized Fermi liquid and the topological Kondo insulator, where the band inversion occurs with the formation of the heavy-fermion band at the same time

Strong-coupling theory of superconductivity in a degenerate Hubbard model

In order to discuss superconductivity in orbital degenerate systems, a microscopic Hamiltonian is introduced. Based on the degenerate model, a strong-coupling theory of superconductivity is developed within the fluctuation exchange (FLEX) approximation where spin and orbital fluctuations, spectra of electron, and superconducting gap function are self-consistently determined. Applying the FLEX approximation to the orbital degenerate model, it is shown that the $d_{x^2-y^2}$-wave superconducting phase is induced by increasing the orbital splitting energy which leads to the development and suppression of the spin and orbital fluctuations, respectively. It is proposed that the orbital splitting energy is a controlling parameter changing from the paramagnetic to the antiferromagnetic phase with the $d_{x^2-y^2}$-wave superconducting phase in between.Comment: 4 figures, submitted to PR

Phase II Clinical Trial for Newly Diagnosed Children and Adolescents with Localized Lymphoblastic Lymphoma (Japanese Leukemia/Lymphoma Study Group Trial LLB-NHL03) : Study Protocol for Nationwide Multicenter Trial

Pediatric patients with lymphoblastic lymphoma are generally treated using the Berlin-Frankfurt-Munster (BFM) 90 protocol, which is the standard treatment strategy for pediatric acute lymphoblastic leukemia, and have a favorable outcome. However, this intense regimen includes high total doses of anthracycline and alkylating agents, and is known to cause late complications. We therefore planned a clinical trial to examine the efficacy and safety of a modified BFM regimen. We expect that this phase II, nationwide multicenter trial will help to establish an effective and safer standard therapy for stage I/II pediatric lymphoblastic lymphoma