Biomedical subjects

R M Konik

Publications and source records attributed to R M Konik.

3 recordsLinked to original sources

PubMed2006

Doped spin liquid: Luttinger sum rule and low temperature order.

We analyze a model of two-leg Hubbard ladders weakly coupled by interladder tunneling. At half filling a semimetallic state with small Fermi pockets is induced beyond a threshold tunneling strength. The sign changes in the single electron Green's function relevant for the Luttinger sum rule now take place at surfaces with both zeros and infinities with important consequences for the interpretation of angle-resolved photoemission spectroscopy experiments. Residual interactions between electron and holelike quasiparticles cause a transition to long range order at low temperatures. The theory can be extended to small doping leading to superconducting order.

Journal Article↗

PubMed2003

Fano line shapes reconsidered: symmetric photoionization peaks from pure continuum excitation.

In a photoionization spectrum in which there is no excitation of the discrete states, but only the underlying continuum, we have observed resonances which appear as symmetric peaks, not the commonly expected window resonances. Furthermore, since the excitation to the unperturbed continuum vanishes, the cross section expected from Fano's configuration interaction theory is identically zero. This shortcoming is removed by the explicit introduction of the phase shifted continuum, which demonstrates that the shape of a resonance, by itself, provides no information about the relative excitation amplitudes to the discrete state and the continuum.

Journal Article↗

PubMed2001

Transport through quantum dots: analytic results from integrability.

Recent experiments have probed quantum dots through transport measurements in the regime where they are described by a two lead Anderson model. In this paper we develop a new method to analytically compute the corresponding transport properties. This is done by using the exact solvability of the Anderson Hamiltonian, together with a generalization of the Landauer-Büttiker approach to integrable systems. In the Kondo regime, we compute analytically for the first time the zero-field, finite temperature linear response conductance, as well as giving closed form expressions describing the zero-temperature, nonequilibrium conductance in an applied Zeeman field.

Journal Article↗