Phase Space Tomography of Classical and Nonclassical Vibrational States of Atoms in an Optical Lattice

Atoms trapped in optical lattice have long been a system of interest in the AMO community, and in recent years much study has been devoted to both short- and long-range coherence in this system, as well as to its possible applications to quantum information processing. Here we demonstrate for the first time complete determination of the quantum phase space distributions for an ensemble of $^{85}Rb$ atoms in such a lattice, including a negative Wigner function for atoms in an inverted state.Comment: Submitted to Journal of Optics B: Quantum and Semiclassical Optics. Special issue in connection with the 9th International Conference on Squeezed States and Uncertainty Relations, to be held in Besancon, France, on 2-6 May 200

Coherent control of population transfer between vibrational states in an optical lattice via two-path quantum interference

We demonstrate coherent control of population transfer between vibrational states in an optical lattice by using interference between a one-phonon transition at $2\omega$ and a two-phonon transition at $\omega$. The $\omega$ and $2\omega$ transitions are driven by phase- and amplitude-modulation of the lattice laser beams, respectively. By varying the relative phase between these two pathways, we control the branching ratio of transitions to the first excited state and to the higher states. Our best result shows an improvement of the branching ratio by a factor of 3.5$\pm$0.7. Such quantum control techniques may find broad application in suppressing leakage errors in a variety of quantum information architectures.Comment: 5 pages, 4 figure

Measurement and characterization of sub-5 fs broadband UV pulses in the 230-350 nm range

We report a new design of all-reflective 3rd-order frequency resolved optical gating setup (FROG) for measurement and characterization of ultrashort UV-pulses in the 230-350 nm range and tested it using 7.3 fs pulses generated in the 250-300 nm range. This setup allows also heterodyne detection which significantly increases its sensitivity

Broadband electronic two-dimensional spectroscopy in the deep UV

We developed an all-reflective fully-noncollinear setup for two-dimensional electronic spectroscopy in the broadband UV (2DUV) with great phase stability (L/150) and applied it to the UV-chromophores dissolved in ethanol using 8-fs UV-pulses, generated in the 245-300 nm range. We are able to resolve 2D-spectra in the ~6000 cm-1 spectral window

Investigating Quantum Electronic or Vibronic Coherences via Energy Migration Dynamics in Light-Harvesting Complex II

The possibility of quantum electronic coherence in photosynthetic complexes is a hotly-debated topic. Our two-dimensional spectroscopic results at physiologically-relevant temperatures attribute these commonly-seen oscillations to vibrational, instead of excitonic, origins. Expanding our laser excitation wavelength into the vibronic shoulder of the complex should provide the smoking gun for the vibrational nature of the oscillations

Chemical Weapons, Ayatollah Khomeini and Islamic Law

Peer reviewe

Dynamic Functional Connectivity in the Musical Brain

Musical training causes structural and functional changes in the brain due to its sensory-motor demands. This leads to differences in how musicians perceive and process music as compared to non-musicians, thereby providing insights into brain adaptations and plasticity. Correlational studies and network analysis investigations have indicated the presence of large-scale brain networks involved in the processing of music and have highlighted differences between musicians and non-musicians. However, studies on functional connectivity in the brain during music listening tasks have thus far focused solely on static network analysis. Dynamic Functional Connectivity (DFC) studies have lately been found useful in unearthing meaningful, time-varying functional connectivity information in both resting-state and task-based experimental settings. In this study, we examine DFC in the fMRI obtained from two groups of participants, 18 musicians and 18 non-musicians, while they listened to a musical stimulus in a naturalistic setting. We utilize spatial Group Independent Component Analysis (ICA), sliding time window correlations, and a deterministic agglomerative clustering of windowed correlation matrices to identify quasi-stable Functional Connectivity (FC) states in the two groups. To compute cluster centroids that represent FC states, we devise and present a method that primarily utilizes windowed correlation matrices occurring repeatedly over time and across participants, while excluding matrices corresponding to spontaneous fluctuations. Preliminary analysis indicate states with greater visuo-sensorimotor integration in musicians, larger presence of DMN states in non-musicians, and variability in states found in musicians due to differences in training and prior experiences.peerReviewe