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Full-Text Articles in Physical Sciences and Mathematics
Dipole-Dipole Interaction Between Rubidium Rydberg Atoms, Emily Altiere, Donald P. Fahey, Michael W. Noel, Rachel J. Smith, Thomas J. Carroll
Dipole-Dipole Interaction Between Rubidium Rydberg Atoms, Emily Altiere, Donald P. Fahey, Michael W. Noel, Rachel J. Smith, Thomas J. Carroll
Physics and Astronomy Faculty Publications
Ultracold Rydberg atoms in a static electric field can exchange energy via the dipole-dipole interaction. The Stark effect shifts the energy levels of the atoms which tunes the energy exchange into resonance at specific values of the electric field (F¨orster resonances). We excite rubidium atoms to Rydberg states by focusing either a 480 nm beam from a tunable dye laser or a pair of diode lasers into a magneto-optical trap. The trap lies at the center of a configuration of electrodes. We scan the electric field by controlling the voltage on the electrodes while measuring the fraction of atoms that …
Local Origins Of Volume Fraction Fluctuations In Dense Granular Materials, James G. Puckett, Frederic Lechenault, Karen E. Daniels
Local Origins Of Volume Fraction Fluctuations In Dense Granular Materials, James G. Puckett, Frederic Lechenault, Karen E. Daniels
Physics and Astronomy Faculty Publications
Fluctuations of the local volume fraction within granular materials have previously been observed to decrease as the system approaches jamming.We experimentally examine the role of boundary conditions and interparticle friction μ on this relationship for a dense granular material of bidisperse particles driven under either constant volume or constant pressure.Using a radicalVorono¨ı tessellation, we find the variance of the local volume fraction φ monotonically decreases as the system becomes more dense, independent of boundary condition and μ. We examine the universality and origins of this trend using experiments and the recent granocentric model, modified to draw particle locations from an …