1,076,573 research outputs found

    Long range statistical fluctuations of the crossed Josephson current

    Full text link
    We investigate the crossed Josephson effect in a geometry consisting of a double ferromagnetic bridge between two superconductors, with tunnel interfaces. The crossed Josephson current vanishes on average because the Andreev reflected hole does not follow the same sequence of impurities as the incoming electron. We show that i) the root mean square of the crossed Josephson current distribution is proportional to the square root of the junction area; and ii) the coherent coupling mediated by fluctuations is ``long range'' since it decays over the ferromagnet phase coherence length lϕl_\phi, larger than the exchange length. We predict a crossed Josephson current due to fluctuations if the length of the ferromagnets is smaller than lϕl_\phi and larger than the exchange length Οh\xi_h.Comment: 8 pages, 3 figures, modifications in the presentatio

    A Non-supersymmetric Large N CFT from Type 0 String Theory

    Full text link
    We show that type 0B theory has a classical AdS_5 x S^5 solution and argue that it is stable at the string-theory level for small enough radius. The dual 4-d conformal field theory is the infrared limit of the theory on N electric D3-branes coincident with N magnetic D3-branes. We explicitly construct this SU(N) x SU(N) gauge theory with global SO(6) symmetry and verify that the one-loop term in the beta function vanishes exactly, while the two-loop term vanishes in the large N limit. We find that this theory is related by a certain projection to the maximally supersymmetric Yang-Mills theory suggesting its large N conformal invariance to all orders in perturbation theory.Comment: 15 pages, harvmac. v2: references and a note on renormalization of Yukawa and scalar couplings added; v3: a note on orbifold interpretation added; the version to appear in JHE

    Pressure-induced spin-state transition of iron in magnesiow\"ustite (Fe,Mg)O

    Full text link
    We present a detailed theoretical study of the electronic, magnetic, and structural properties of magnesiow\"ustite Fe1−x_{1-x}Mgx_xO with xx in the range between 0−-0.875 using a fully charge self-consistent implementation of the density functional theory plus dynamical mean-field theory (DFT+DMFT) method. In particular, we compute the electronic structure and phase stability of the rock-salt B1-structured (Fe,Mg)O at high pressures relevant for the Earth's lower mantle. We obtain that upon compression paramagnetic (Fe,Mg)O exhibits a spin-state transition of Fe2+^{2+} ions from a high-spin to low-spin (HS-LS) state which is accompanied by a collapse of local magnetic moments. The HS-LS transition results in a substantial drop of the lattice volume by about 4−-8 %, implying a complex interplay between electronic and lattice degrees of freedom. Our results reveal a strong sensitivity of the calculated transition pressure Ptr.P_{\rm tr.} upon addition of Mg. While for Fe-rich magnesiow\"ustite, Mg x<0.5x < 0.5, Ptr.P_{\rm tr.} exhibits a rather weak variation at ∌\sim80 GPa, for Fe-poor (Fe,Mg)O it drops, e.g., by about 35 % to 52 GPa for Mg x=0.75x=0.75. This behavior is accompanied by a substantial change of the spin transition range from 50−-140 GPa in FeO to 30−-90 GPa for x=0.75x=0.75. In addition, the calculated bulk modulus (in the HS state) is found to increase by ∌\sim12 % from 142 GPa in FeO to 159 GPa in (Fe,Mg)O with Mg x=0.875x=0.875. We find that the pressure-induced HS-LS transition has different consequences for the electronic properties of the Fe-rich and poor (Fe,Mg)O. For the Fe-rich (Fe,Mg)O, the transition is found to be accompanied by a Mott insulator to (semi-) metal phase transition. In contrast to that, for x>0.25x>0.25, (Fe,Mg)O remains insulating up to the highest studied pressures, implying a Mott insulator to band insulator phase transition at the HS-LS transformation.Comment: 9 pages, 9 figure

    KEDUDUKAN AHLI WARIS NON MUSLIM DALAM KEWARISAN ISLAM (STUDI KASUS PUTUSAN NOMOR : 1578/PDT.G/2010/PA.JT)

    Get PDF
    Salah satu pembahasan dalam ilmu mawaris adalah pembahasan tentang penghalang dalam kewarisan. Penghalang dalam kewarisan ada tiga penyebabnya yaitu pembunuhan yang disengaja, beda agama dan perbudakan. Beda agama adalah apabila antara ahli waris dan pewaris salah satunya beragama Islam dan yang lain tidak beragama Islam. Tentang perbedaan agama antara pewaris dan ahli waris, dapat menggugurkan hak seseorang untuk mewarisi harta peninggalan. Rumusan masalah dalam penelitian ini ialah bagaimana kedudukan ahli waris non muslim dalam kewarisan Islam dan apakah pertimbangan Hakim dalam putusan nomor : 1578/Pdt.G/2010/PA.JT telah sesuai dengan hukum Islam serta Kompilasi Hukum Islam. Metode pendekatan yang digunakan peneliti adalah library research (yurudis normatif). Yaitu suatu pendekatan alternatif yang menganalisa bahan-bahan pustaka di bidang hukum yang norma- normanya tertulis dan spesifikasi penelitian deskriptis analitis, yaitu dengan menggunakan metode dan teori ilmu-ilmu sosial tentang hukum untuk membantu peneliti dalam melakukan analisis. Hasil dari penelitian ini diperoleh kesimpulan yakni : (1) Hukum Islam menegaskan prinsip dalam kewarisan bahwa ahli waris non muslim tidak mempunyai kedudukan untuk mewarisi harta dari pewaris muslim, sebagaimana yang telah diatur dalam Al-Qur’an, Hadits serta Kompilasi Hukum Islam. (2) Dalam pertimbangan hakim Pengadilan Agama Jakarta Timur dianggap telah terjadi kekeliruan mengenai pemahaman tentang kompetensi absolut Pengadilan Negeri Jakarta Timur yang menetapkan masalah kewarisan Islam, karena pada dasarnya yang mempunyai kewenangan absolut ialah Pengadilan Agama Jakarta Timur. Hal tersebut menimbulkan dasar penolakan hakim Pengadilan Agama menolak gugatan perkara ahli waris, yang menyebabkan ahli waris non muslim memperoleh kembali hak kewarisannya. Hasil dari putusan tersebut ditinjau secara sudut pandang Islam sangat bertentangan dengan Al- Qur’an dan Hadits serta ketentuan menurut perspektif Kompilasi Hukum Islam, bahwa mengenai sistem kewarisan Islam tidak mengakui ahli waris non muslim sebagai ahli waris dari pewaris muslim

    Quasiclassical Green function in an external field and small-angle scattering

    Get PDF
    The quasiclassical Green functions of the Dirac and Klein-Gordon equations in the external electric field are obtained with the first correction taken into account. The relevant potential is assumed to be localized, while its spherical symmetry is not required. Using these Green functions, the corresponding wave functions are found in the approximation similar to the Furry-Sommerfeld-Maue approximation. It is shown that the quasiclassical Green function does not coincide with the Green function obtained in the eikonal approximation and has a wider region of applicability. It is illustrated by the calculation of the small-angle scattering amplitude for a charged particle and the forward photon scattering amplitude. For charged particles, the first correction to the scattering amplitude in the non-spherically symmetric potential is found. This correction is proportional to the scattering angle. The real part of the amplitude of forward photon scattering in a screened Coulomb potential is obtained.Comment: 20 pages, latex, 1 figur

    Exciton Condensate Modulation in Electron-Hole Bilayers: A Real-Space Visualization

    Full text link
    We study the texture of the exciton condensate at low temperatures in an independently gated electron-hole bilayer system. A model Hamiltonian is solved in real space within a mean-field approximation. It is found that, with increased electron-hole density polarization, the system experiences phase transformations from the zero center-of-mass momentum superfluid state, through one- and two-dimensional exciton pair modulated states, into the normal state. At weak density polarization, the modulating state resembles the Larkin-Ovchinikov state in superconductors in the presence of an exchange field in the weak-coupling BCS limit, and becomes stripe-like in the strong coupling BEC limit. In the one-dimensional modulated phase, the density of states exhibits low-energy intra-gap resonance quasiparticle states, which are localized in the nodal region.Comment: 4+ pages, 6 eps figure

    Possible quantum kinematics. II. Non-minimal case

    Full text link
    The quantum analogs of the N-dimensional Cayley-Klein spaces with different combinations of quantum and Cayley-Klein structures are described for non-minimal multipliers, which include the first and the second powers of contraction parameters in the transformation of deformation parameter. The noncommutative analogs of (N-1)-dimensional constant curvature spaces are introduced. Part of these spaces for N=5 are interpreted as the noncommutative analogs of (1+3) space-time models. As a result the wide variety of the quantum deformations of realistic kinematics are suggested.Comment: 13 pages, no figure

    The low temperature Fulde-Ferrell-Larkin-Ovchinnikov phases in 3 dimensions

    Full text link
    We consider the nature of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phases in three dimensions at low temperature. We introduce a new method to handle the quasiclassical equations for superconductors with space dependent order parameter, which makes use of a Fourier expansion. This allows us to show that, at T=0, an order parameter given by the linear combination of three cosines oscillating in orthogonal directions is preferred over the standard single cosine solution. The transition from the normal state to this phase is first order, and quite generally the transition below the tricritical point to the FFLO phases is always first order.Comment: 4 pages, revtex, 1 figur

    Vortex tilt modulus in Fulde-Ferrell-Larkin-Ovchinnikov state

    Get PDF
    Vortex tilt response in Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) vortex lattice is theoretically examined as a probe reflecting the spatial structure of this state. In the FFLO state with nodal planes perpendicular to the magnetic field in a quasi 2D material under a parallel field, the tilt modulus E_{2} {\it of the nodal planes} decreases as the paramagnetic effect is effectively enhanced, and this reduction of E_{2} in turn reduces the vortex tilt modulus. This reduction of vortex tilt modulus, more remarkable in more anisotropic systems, accompanying the FFLO transition may be an origin of the monotonous reduction of sound velocity detected upon cooling in a ultrasound measurement for CeCoIn5.Comment: 14 pages, 5 figures. Accepted for publication in Phys. Rev.

    Radio and optical orientations of galaxies

    Full text link
    We investigate the correlations between optical and radio isophotal position angles for 14302 SDSS galaxies with rr magnitudes brighter than 18 and which have been associated with extended FIRST radio sources. We identify two separate populations of galaxies using the colour, concentration and their principal components. Surprisingly strong statistical alignments are found: late-type galaxies are overwhelmingly biased towards a position angle differences of 0∘0^{\circ} and early-type galaxies to 90∘90^{\circ}. The late-type alignment can be easily understood in terms of the standard picture in which the radio emission is intimately related to areas of recent star-formation. In early-type galaxies the radio emission is expected to be driven by accretion on to a nuclear black hole. We argue that the observed correlation of the radio axis with the minor axis of the large-scale stellar distribution gives a fundamental insight into the structure of elliptical galaxies, for example, whether or not the nuclear kinematics are decoupled form the rest of the galaxy. Our results imply that the galaxies are oblate spheroids with their radio emission aligned with the minor axis. Remarkably the strength of the correlation of the radio major axis with the optical minor axis depends on radio loudness. Those objects with a low ratio of FIRST radio flux density to total stellar light show a strong minor axis correlation while the stronger radio sources do not. This may reflect different formation histories for the different objects and we suggest we may be seeing the different behaviour of rationally supported and non-rotationally supported ellipticals.Comment: Version to appear in MNRA
    • 

    corecore