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Full-Text Articles in Physical Sciences and Mathematics
Measurement Of A Weak Transition Moment Using Coherent Control, Dionysios Antypas
Measurement Of A Weak Transition Moment Using Coherent Control, Dionysios Antypas
Open Access Dissertations
We have developed a two-pathway Coherent Control technique for measurements of weak optical transition moments. We demonstrate this technique through a measurement of the transition moment of the highly-forbidden magnetic dipole transition between the 6s2S1/21/2 and 7s2S1/21/2 states in atomic Cesium. The experimental principle is based on a two-pathway excitation, using two phase-coherent laser fields, a fundamental field at 1079 nm and its second harmonic at 539.5 nm. The IR field induces a strong two-photon transition, while the 539.5 nm field drives a pair of weak one-photon transitions: a Stark-induced transition of …
Experimental Studies Of Lirb: Spectroscopy And Ultracold Molecule Formation By Photoassociation, Sourav Dutta
Experimental Studies Of Lirb: Spectroscopy And Ultracold Molecule Formation By Photoassociation, Sourav Dutta
Open Access Dissertations
Heteronuclear polar molecules have recently attracted enormous attention owing to their ground state having a large electric dipole moment. The long range anisotropic dipole-dipole interaction in such systems is the basis for a variety of applications including quantum computing, precision measurements, ultracold chemistry and quantum simulations. Heteronuclear bi-alkali molecules, only a small subset of polar molecules, have received special attention mainly because the constituent alkali atoms are easy to laser cool and can be relatively easily associated to form molecules at ultracold temperatures. Our choice, the LiRb molecule, is motivated by the relatively high dipole moment (4.1 Debye) of the …
Applicability Of Continuum Fracture Mechanics In Atomistic Systems, Shao-Huan Cheng
Applicability Of Continuum Fracture Mechanics In Atomistic Systems, Shao-Huan Cheng
Open Access Dissertations
By quantitating the amplitude of the unbounded stress, the continuum fracture mechanics defines the stress intensity factor K to characterize the stress and displacement fields in the vicinity of the crack tip, thereby developing the relation between the stress singularity and surface energy (energy release rate G). This G-K relation, assigning physical meaning to the stress intensity factor, makes these two fracture parameters widely used in predicting the onset of crack propagation. However, due to the discrete nature of the atomistic structures without stress singularity, there might be discrepancy between the failure prediction and the reality of nanostructured materials. Defining …