Burden of Family Care-Givers and the Rationing in the Long Term Care Insurance Benefits of Japan

Long Term Care Insurance introduced in Japan in 2000 is rapidly turning into a system of rationed benefits due to financial difficulty. Based on our survey of 2500 family care-givers and the Zarit Care-Giver Burden Index, we have examined how these changes are affecting their subjective burden, following Kishida's seminary work. We have found evidence that (a)rationings in short-term-stays, day-services, or home-helper services, (b)disruptive or anti-social behaviors of the elderly, and (c)care-giver's own sleeping disorders are substantially adding to their burden. We have also found (d)a causal relationship where a higher burden is resulting in poor self-reported health.Long-term Care Insurance, Burden Index of Care-Givers, Rationning

Study on the Kondo effect in the tunneling phenomena through a quantum dot

We review our recent studies on the Kondo effect in the tunneling phenomena through quantum dot systems. Numerical methods to calculate reliable tunneling conductance are developed. In the first place, a case in which electrons of odd number occupy the dot is studied, and experimental results are analyzed based on the calculated result. Tunneling anomaly in the even-number-electron occupation case, which is recently observed in experiment and is ascribed to the Kondo effect in the spin singlet-triplet cross over transition region, is also examined theoretically.Comment: 9 pages, 5 figures, Proceedings of the 2nd Hiroshima Workshop--Transport and Thermal Properties of Advanced Materials--, Hiroshima, Japan, August 16-19, 200

Phonon-assisted tunneling in interacting suspended single wall carbon nanotubes

Transport in suspended metallic single wall carbon nanotubes in the presence of strong electron-electron interaction is investigated. We consider a tube of finite length and discuss the effects of the coupling of the electrons to the deformation potential associated to the acoustic stretching and breathing modes. Treating the interacting electrons within the framework of the Luttinger liquid model, the low-energy spectrum of the coupled electron-phonon system is evaluated. The discreteness of the spectrum is reflected in the differential conductance which, as a function of the applied bias voltage, exhibits three distinct families of peaks. The height of the phonon-assisted peaks is very sensitive to the parameters. The phonon peaks are best observed when the system is close to the Wentzel-Bardeen singularity.Comment: 14 pages, 3 figure

Quantum energy teleportation in a quantum Hall system

We propose an experimental method for a quantum protocol termed quantum energy teleportation (QET), which allows energy transportation to a remote location without physical carriers. Using a quantum Hall system as a realistic model, we discuss the physical significance of QET and estimate the order of energy gain using reasonable experimental parameters

Transverse profile and three-dimensional spin canting of a Majorana state in carbon nanotubes

The full spatial 3D profile of Majorana bound states (MBS) in a nanowirelike setup featuring a semiconducting carbon nanotube (CNT) as the central element is discussed. By atomic tight-binding calculations, we show that the chiral nature of the CNT lattice is imprinted in the MBS wave function which has a helical structure, anisotropic in the transverse direction. The local spin-canting angle displays a similar spiral pattern, varying around the CNT circumference. We reconstruct the intricate 3D profile of the MBS wave function analytically, using an effective low-energy Hamiltonian accounting both for the electronic spin and valley degrees of freedom of the CNT. In our model, the four components of the Majorana spinor are related by the three symmetries of our Bogoliubov-de Gennes Hamiltonian, reducing the number of independent components to one. A Fourier transform analysis uncovers the presence of three contributions to the MBS, one from the Gamma-point and one from each of the Fermi points, with further complexity added by the presence of two valley states in each contribution

Majorana quasiparticles in semiconducting carbon nanotubes

Engineering effective p-wave superconductors hosting Majorana quasiparticles (MQPs) is nowadays of particular interest, also in view of the possible utilization of MQPs in fault-tolerant topological quantum computation. In quasi-one-dimensional systems, the parameter space for topological superconductivity is significantly reduced by the coupling between transverse modes. Together with the requirement of achieving the topological phase under experimentally feasible conditions, this strongly restricts in practice the choice of systems which can host MQPs. Here, we demonstrate that semiconducting carbon nanotubes (CNTs) in proximity with ultrathin s-wave superconductors, e.g., exfoliated NbSe2, satisfy these needs. By precise numerical tight-binding calculations in the real space, we show the emergence of localized zero-energy states at the CNT ends above a critical value of the applied magnetic field, of which we show the spatial evolution. Knowing the microscopic wave functions, we unequivocally demonstrate the Majorana nature of the localized states. An effective four-band model in the k-space, with parameters determined from the numerical spectrum, is used to calculate the topological phase diagram and its phase boundaries in analytic form. Finally, the impact of symmetry breaking contributions, like disorder and an axial component of the magnetic field, is investigated

Dynamics of quantum cellular automata electron transition in triple quantum dots

The quantum cellular automata (QCA) effect is a transition in which multiple electron move coordinately by Coulomb interactions and observed in multiple quantum dots. This effect will be useful for realizing and improving quantum cellular automata and information transfer using multiple electron transfer. In this paper, we investigate the real-time dynamics of the QCA charge transitions in a triple quantum dot by using fast charge-state readout realized by rf reflectometry. We observe real-time charge transitions and analyze the tunneling rate comparing with the first-order tunneling processes. We also measure the gate voltage dependence of the QCA transition and show that it can be controlled by the voltage.Comment: 11pages, 4 figure