3,011 research outputs found

    Note on the Electron Energy Spectrum in the Inner Van Allen Belt

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    Electron energy spectrum in the inner van allen bel

    Geomagnetically Trapped Radiation Produced by a High-Altitude Nuclear Explosion on July 9, 1962

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    Geomagnetically trapped radiation produced by a high altitude nuclear explosio

    Hierarchy wave functions--from conformal correlators to Tao-Thouless states

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    Laughlin's wave functions, describing the fractional quantum Hall effect at filling factors ν=1/(2k+1)\nu=1/(2k+1), can be obtained as correlation functions in conformal field theory, and recently this construction was extended to Jain's composite fermion wave functions at filling factors ν=n/(2kn+1)\nu=n/(2kn+1). Here we generalize this latter construction and present ground state wave functions for all quantum Hall hierarchy states that are obtained by successive condensation of quasielectrons (as opposed to quasiholes) in the original hierarchy construction. By considering these wave functions on a cylinder, we show that they approach the exact ground states, the Tao-Thouless states, when the cylinder becomes thin. We also present wave functions for the multi-hole states, make the connection to Wen's general classification of abelian quantum Hall fluids, and discuss whether the fractional statistics of the quasiparticles can be analytically determined. Finally we discuss to what extent our wave functions can be described in the language of composite fermions.Comment: 9 page

    Pairing via Index theorem

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    This work is motivated by a specific point of view: at short distances and high energies the undoped and underdoped cuprates resemble the π\pi-flux phase of the t-J model. The purpose of this paper is to present a mechanism by which pairing grows out of the doped π\pi-flux phase. According to this mechanism pairing symmetry is determined by a parameter controlling the quantum tunneling of gauge flux quanta. For zero tunneling the symmetry is dx2y2+idxyd_{x^2-y^2}+id_{xy}, while for large tunneling it is dx2y2d_{x^2-y^2}. A zero-temperature critical point separates these two limits

    Experimental determination of dipole moments for molecular ions: Improved measurements for ArH^+

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    An improved value for the dipole moment of ArH^+ has been obtained from new measurements of the rotational g factors of ArH^+ and ArD^+ made with tunable far‐IR laser spectroscopy. Systematic errors present in earlier measurements have been eliminated. The new result (μ=3.0±0.6 D) is slightly higher than the ab initio value of Rosmus (2.2 D) at the 2σ limits of precision

    Fractional Quantum Hall Effect and vortex lattices

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    It is demonstrated that all observed fractions at moderate Landau level fillings for the quantum Hall effect can be obtained without recourse to the phenomenological concept of composite fermions. The possibility to have the special topologically nontrivial many-electron wave functions is considered. Their group classification indicates the special values of of electron density in the ground states separated by a gap from excited states

    A First-Landau-Level Laughlin/Jain Wave Function for the Fractional Quantum Hall Effect

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    We show that the introduction of a more general closed-shell operator allows one to extend Laughlin's wave function to account for the richer hierarchies (1/3, 2/5, 3/7 ...; 1/5, 2/9, 3/13, ..., etc.) found experimentally. The construction identifies the special hierarchy states with condensates of correlated electron clusters. This clustering implies a single-particle (ls)j algebra within the first Landau level (LL) identical to that of multiply filled LLs in the integer quantum Hall effect. The end result is a simple generalized wave function that reproduces the results of both Laughlin and Jain, without reference to higher LLs or projection.Comment: Revtex. In this replacement we show how to generate the Jain wave function explicitly, by acting with the generalized ls closed-shell operator discussed in the original version. We also walk the reader through a classical 1d caricature of this problem so that he/she can better understand why 2s+1, where s is the spin, should be associated with the number of electrons associated with the underlying clusters or composites. 11 page

    Meron excitations in the nu =1 quantum Hall bilayer and the plasma analogy

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    We study meron quasiparticle excitations in the \nu = 1 quantum Hall bilayer. Considering the well known single meron state, we introduce its effective form, valid in the longdistance limit. That enables us to propose two (and more) meron states in the same limit. Further, establishing a plasma analogy of the (111) ground state, we find the impurities that play the role of merons and derive meron charge distributions. Using the introduced meron constructions in generalized (mixed) ground states and corresponding plasmas for arbitrary distance between the layers, we calculate the interaction between the construction implied impurities. We also find a correspondence between the impurity interactions and meron interactions. This suggests a possible explanation of the deconfinement of the merons recently observed in the experiments.Comment: 5 pages, 3 figure

    Spin Susceptibility and Gap Structure of the Fractional-Statistics Gas

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    This paper establishes and tests procedures which can determine the electron energy gap of the high-temperature superconductors using the t ⁣ ⁣Jt\!-\!J model with spinon and holon quasiparticles obeying fractional statistics. A simpler problem with similar physics, the spin susceptibility spectrum of the spin 1/2 fractional-statistics gas, is studied. Interactions with the density oscillations of the system substantially decrease the spin gap to a value of (0.2±0.2)(0.2 \pm 0.2) ωc\hbar \omega_c, much less than the mean-field value of ωc\hbar\omega_c. The lower few Landau levels remain visible, though broadened and shifted, in the spin susceptibility. As a check of the methods, the single-particle Green's function of the non-interacting Bose gas viewed in the fermionic representation, as computed by the same approximation scheme, agrees well with the exact results. The same mechanism would reduce the gap of the t ⁣ ⁣Jt\!-\!J model without eliminating it.Comment: 35 pages, written in REVTeX, 16 figures available upon request from [email protected]

    Band Structure of the Fractional Quantum Hall Effect

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    The eigenstates of interacting electrons in the fractional quantum Hall phase typically form fairly well defined bands in the energy space. We show that the composite fermion theory gives insight into the origin of these bands and provides an accurate and complete microscopic description of the strongly correlated many-body states in the low-energy bands. Thus, somewhat like in Landau's fermi liquid theory, there is a one-to-one correspondence between the low energy Hilbert space of strongly interacting electrons in the fractinal quantum Hall regime and that of weakly interacting electrons in the integer quantum Hall regime.Comment: 10 page
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