We give a new and simple compactness criterion for composition operators Cφ on BMOA and the Bloch space in terms of the norms of φ in the respective spaces.

The fine-structure spots in an electron diffraction pattern from a crystal wedge represent the strong partial waves of strongly excited Bloch waves. Diffraction experiments near the [100] and the [110] zone axes of a CaF, crystal were carried out in order to determine from a fine-structure profile analysis the low-indexed structure potentials V n i , V200 and V220 the absorption coefficients of...

We define and characterize the harmonic Besov space Bp, 1 ≤ p ≤ ∞, on the unit ball B in Rn. We prove that the Besov spaces Bp, 1 ≤ p ≤ ∞, are natural quotient spaces of certain Lp spaces. The dual of Bp, 1 ≤ p < ∞, can be identified with Bq , 1/p + 1/q = 1, and the dual of the little harmonic Bloch space B0 is B1.

We experimentally study dispersive shock waves in nonlinear waveguide arrays. In contrast with gap solitons, the nonlinearity here pushes the propagation constant further into the transmission bands, facilitating Bloch mode coupling and energy transport. We directly observe this coupling, both within and between bands, by recording intensity in position space and power spectra in momentum space.

The Bloch equation provides the fundamental description of nuclear magnetic resonance(NMR) and relaxation(T1 andT2). This equation is the basis for both NMR spectroscopy andmagnetic resonance imaging (MRI). The fractional-order Bloch equation is a generalizationof the integer-order equation that interrelates the precession of the x, y and z componentsof magnetization wit...

Starting from Bloch equation for a canonical ensemble, we deduce a set of hierarchy equations for the reduced statistical density operator for an identical many-body system with two-body interaction. They provide a law according to which the reduced density operator varies in temperature. By definition of the reduced density operator in Fock space for a grand canonical ensemble, we also obtain ...

We study harmonic Bergman functions on the upper half-space of Rn. Among our main results are: The Bergman projection is bounded for the range 1 < p <∞; certain nonorthogonal projections are bounded for the range 1 ≤ p < ∞; the dual space of the Bergman L1-space is the harmonic Bloch space modulo constants; harmonic conjugation is bounded on the Bergman spaces for the range 1 ≤ p <∞; the Bergma...

Starting from Bloch equation for a canonical ensemble, we deduce a set of hierarchy equations for the reduced statistical density operator for an identical many-body system with two-body interaction. They provide a law according to which the reduced density operator varies in temperature. By definition of the reduced density operator in Fock space for a grand canonical ensemble, we also obtain ...

We study the homogenization of a Schrödinger equation in a periodic medium with a time dependent potential. This is a model for semiconductors excited by an external electromagnetic wave. We prove that, for a suitable choice of oscillating (both in time and space) potential, one can partially transfer electrons from one Bloch band to another. This justifies the famous ”Fermi golden rule” for th...

Products of integral-type and composition operators has been recently introduced by Li and Stević and studied in a series of their papers. In this note we study the boundedness and compactness of these products from generally weighted Bloch space to F (p, q, s) space, where 0 < p, s < ∞, q > −2, α > 0.