Biomedical subjects

S Chelkowski

Publications and source records attributed to S Chelkowski.

12 recordsLinked to original sources

PubMed2005

Limits on gravitational-wave emission from selected pulsars using LIGO data.

We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10(-24). These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10(-5) for the four closest pulsars.

Journal Article↗

PubMed2001

Dynamic imaging of nuclear wave functions with ultrashort UV laser pulses.

Non-Born-Oppenheimer supercomputer simulations of dissociative ionization of H2(+) with an ultrashort (t(p) < 15 fs), intense UV (lambda = 30, 60 nm) laser pulse are used to illustrate the imaging of nuclear motion. The resulting kinetic energy spectra of protons from Coulomb explosion lead by a simple inversion procedure to reconstruction of the initial nuclear probability distribution, i.e., laser Coulomb explosion imaging. Simultaneously, kinetic energy spectra of the ionized electron lead by energy conservation to the same reconstruction of the initial nuclear probability distribution, by laser photoelectron imaging.

Journal Article↗

PubMed2000

Asymmetric electron-nuclear dynamics in two-color laser fields: laser phase directional control of photofragments in H+2

Exact non-Born-Oppenheimer numerical solutions of the time-dependent Schrodinger equation for the 1D H+2 molecule in an intense, two-color (omega+2omega) laser field have been obtained. Both electron and proton kinetic energy spectra show spatial, correlated, asymmetric distributions. The calculated spectra exhibit the same unusual correlations as in experiments, in which both positively charged nuclear fragments and negatively charged photoelectrons were preferentially emitted in the same direction. The above asymmetries of photoemission of electrons seen in our quantum simulation are interpreted in the framework of a quasistatic tunneling model.

Journal Article↗

PubMed1996