131 research outputs found

    A systematic review of interpersonal processes and their measurement within experience sampling studies of self-injurious thoughts and behaviours

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    Self-injurious thoughts and behaviours (SITBs) are a leading cause of death, and interpersonal processes (IPs) appear to play a role in SITBs. This systematic review synthesises the literature on IPs and SITBs in daily life and addresses four critical questions: (1) Which IPs have been assessed and how, (2) What is the relationship between IPs and SITBs in daily life?, (3) Do daily-life fluctuations in IPs differ between individuals with and without SITBs?, and (4) Do IPs relate differently to self-injurious thoughts than behaviours? Our review followed PRISMA guidelines and eligible literature was screened until 29 August 2023. We identified 52 Experience Sampling studies (34.62% daily-diary studies) of which most focused on IPs from suicide theories (e.g., thwarted belongingness) but largely used inconsistent operationalizations. Results from 35 studies investigating within-person associations were mixed. Based on 24 studies, whether individuals with and without SITBs differ in their interpersonal experiences remains unclear. Four studies have investigated whether IPs relate to the transition from thoughts to behaviours, but temporal models are needed to draw firm conclusions. Studies investigating IPs and SITBs in daily life are largely inconclusive. Psychometrically validated measures are warranted, and future daily-life studies would benefit from drawing on ideation-to-action frameworks

    Half-Periodic Josephson Effect in an s-Wave Superconductor - Normal Metal -d-Wave Superconductor Junction

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    We predict that the Josephson current in a clean s-wave superconductor-normal metal-d-wave superconductor junction is periodic in superconducting phase difference ϕ\phi with period π\pi instead of 2π2\pi. The frequency of non-stationary Josephson effect is correspondingly 2ωJ=4eV.2\omega_J = 4eV. The effect is due to coexistence in the normal layer of current carrying Andreev levels with phase differences ϕ\phi and ϕ+π.\phi+\pi.Comment: 4 pages, REVTeX, 3 figure

    Extended bound states and resonances of two fermions on a periodic lattice

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    The high-TcT_c cuprates are possible candidates for d-wave superconductivity, with the Cooper pair wave function belonging to a non-trivial irreducible representation of the lattice point group. We argue that this d-wave symmetry is related to a special form of the fermionic kinetic energy and does not require any novel pairing mechanism. In this context, we present a detailed study of the bound states and resonances formed by two lattice fermions interacting via a non-retarded potential that is attractive for nearest neighbors but repulsive for other relative positions. In the case of strong binding, a pair formed by fermions on adjacent lattice sites can have a small effective mass, thereby implying a high condensation temperature. For a weakly bound state, a pair with non-trivial symmetry tends to be smaller in size than an s-wave pair. These and other findings are discussed in connection with the properties of high-TcT_c cuprate superconductors.Comment: 21 pages, RevTeX, 4 Postscript figures, arithmetic errors corrected. An abbreviated version (no appendix) appeared in PRB on March 1, 199

    Fluxoid dynamics in superconducting thin film rings

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    We have measured the dynamics of individual magnetic fluxoids entering and leaving photolithographically patterned thin film rings of the underdoped high-temperature superconductor Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}, using a variable sample temperature scanning SQUID microscope. These results can be qualitatively described using a model in which the fluxoid number changes by thermally activated nucleation of a Pearl vortex in, and transport of the Pearl vortex across, the ring wall.Comment: 9 pages, 10 figures, fixed typo

    Vortices and Quantum tunneling in Current-Biased 0-\pi-0 Josephson Junctions of d-wave Superconductors

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    We study a current-biased 0-\pi-0 Josephson junction made by high-T_c superconductors, theoretically. When a length of the \pi junction is large enough, this junction contains a vortex-antivortex pair at both ends of the \pi junction. Magnetic flux carried by the vortices is calculated using the sine-Gordon equation. The result shows that the magnetic flux of the vortices is suppressed to zero as the distance between the vortices is reduced. By applying an external current, the orientation of the vortices is reversed, and a voltage pulse is generated. The current needed for this transition and generated pulse energy are calculated. Macroscopic quantum tunneling (MQT) in this transition is also studied. The tunneling rate has been evaluated by an effective Hamiltonian with one degree of freedom.Comment: 12 pages, LaTeX with 5 PS figures, using jpsj.st

    Superconducting gap node spectroscopy using nonlinear electrodynamics

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    We present a method to determine the nodal structure of the energy gap of unconventional superconductors such as high TcT_c materials. We show how nonlinear electrodynamics phenomena in the Meissner regime, arising from the presence of lines on the Fermi surface where the superconducting energy gap is very small or zero, can be used to perform ``node spectroscopy'', that is, as a sensitive bulk probe to locate the angular position of those lines. In calculating the nonlinear supercurrent response, we include the effects of orthorhombic distortion and aba-b plane anisotropy. Analytic results presented demonstrate a systematic way to experimentally distinguish order parameters of different symmetries, including cases with mixed symmetry (for example, d+sd+s and s+ids+id). We consider, as suggested by various experiments, order parameters with predominantly dd-wave character, and describe how to determine the possible presence of other symmetries. The nonlinear magnetic moment displays a distinct behavior if nodes in the gap are absent but regions with small, finite, values of the energy gap exist.Comment: 18 pages, Revtex, 9 postscript figures. Submitted to Phys. Rev

    Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor

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    In the presence of an external magnetic field, the low lying elementary excitations of a d-wave superconductor have quantized energy and their momenta are locked near the node direction. It is argued that these discrete states can most likely be detected by a local probe, such as a scanning tunneling microscope. The low temperature local tunneling conductance on the Wigner-Seitz cell boundaries of the vortex lattice is predicted to show peaks spaced as ±n,n=0,1,2,...\pm \sqrt{n}, n ={0,1,2, ...}. The n=0n=0 peak is anomalous, and it is present only if the superconducting order parameter changes sign at certain points on the Fermi surface. Away from the cell boundary, where the superfluid velocity is nonzero, each peak splits, in general, into four peaks, corresponding to the number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included

    Frustrated kinetic energy, the optical sum rule, and the mechanism of superconductivity

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    The theory that the change of the electronic kinetic energy in a direction perpendicular to the CuO-planes in high-temperature superconductors is a substantial fraction of the condensation energy is examined. It is argued that the consequences of this theory based on a rigorous cc-axis conductivity sum rule are consistent with recent optical and penetration depth measurements.Comment: 4 pages (RevTeX) and 2 eps figure

    Nanoscopic Tunneling Contacts on Mesoscopic Multiprobe Conductors

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    We derive Bardeen-like expressions for the transmission probabilities between two multi-probe mesoscopic conductors coupled by a weak tunneling contact. We emphasize especially the dual role of a weak coupling contact as a current source and sink and analyze the magnetic field symmetry. In the limit of a point-like tunneling contact the transmission probability becomes a product of local, partial density of states of the two mesoscopic conductors. We present expressions for the partial density of states in terms of functional derivatives of the scattering matrix with respect to the local potential and in terms of wave functions. We discuss voltage measurements and resistance measurements in the transport state of conductors. We illustrate the theory for the simple case of a scatterer in an otherwise perfect wire. In particular, we investigate the development of the Hall-resistance as measured with weak coupling probes.Comment: 10 pages, 5 figures, revte

    Multiband model of high Tc superconductors

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    We propose an extension to other high T_{c } compounds of a model introduced earlier for YBCO. In the ''self-doped'' compounds we assume that the doping part (namely the BiO, HgO, TlO planes in BSCCO, HBCCO, TBCCO respectively) is metallic, which leads to a multiband model. This assumption is supported by band structure calculations. Taking a repulsive pairing interaction between these doping bands and the CuO_{2} bands leads to opposite signs for the order parameter on these bands and to nodes whenever the Fermi surfaces of these bands cross. We show that in BSCCO the low temperature dependence of the penetration depth is reasonably accounted for. In this case the nodes are not located near the 45^{o} direction, which makes the experimental determination of the node locations an important test for our model. The situation in HBCCO and TBCCO is rather analogous to BSCCO. We consider the indications given by NMR and find that they rather favor a metallic character for the doping bands. Finally we discuss the cases of NCCO and LSCO which are not ''self-doped'' and where our model does not give nodes.Comment: 11 pages, revtex, 1 figure
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