Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physics
Evolution Of Magnetic-Field-Induced Ordering In The Layered Structure Quantum Heisenberg Triangular-Lattice Antiferromagnet Ba3Cosb2O9, Nathanael Alexander Fortune, Q. Huang, T. Hong, J. Ma, E. S. Choi, S. T. Hannahs, Z. Y. Zhao, X. F. Sun, Y. Takano, H. D. Zhou
Evolution Of Magnetic-Field-Induced Ordering In The Layered Structure Quantum Heisenberg Triangular-Lattice Antiferromagnet Ba3Cosb2O9, Nathanael Alexander Fortune, Q. Huang, T. Hong, J. Ma, E. S. Choi, S. T. Hannahs, Z. Y. Zhao, X. F. Sun, Y. Takano, H. D. Zhou
Physics: Faculty Publications
Quantum fluctuations in the effective spin-1/2 layered structure triangular-lattice quantum Heisenberg antiferromagnet Ba3CoSb2O9 lift the classical degeneracy of the antiferromagnetic ground state in magnetic field, producing a series of novel spin structures for magnetic fields applied within the crystallographic ab plane, including a celebrated collinear ‘up-up-down’ spin ordering with magnetization equal to 1/3 of the saturation magnetization over an extended field range. Theoretically unresolved, however, are the effects of interlayer antferromagnetic coupling and transverse magnetic fields on the ground states of this system. Additional magnetic-field-induced phase transitions are theoretically expected and in some cases have …
Vortex-Antivortex Physics In Shell-Shaped Bose-Einstein Condensates, Karmela Padavić, Kuei Sun, Courtney Lannert, Smitha Vishveshwara
Vortex-Antivortex Physics In Shell-Shaped Bose-Einstein Condensates, Karmela Padavić, Kuei Sun, Courtney Lannert, Smitha Vishveshwara
Physics: Faculty Publications
Shell-shaped hollow Bose-Einstein condensates (BECs) exhibit behavior distinct from their filled counterparts and have recently attracted attention due to their potential realization in microgravity settings. Here we study distinct features of these hollow structures stemming from vortex physics and the presence of rotation. We focus on a vortex-antivortex pair as the simplest configuration allowed by the constraints on superfluid flow imposed by the closed-surface topology. In the two-dimensional limit of an infinitesimally thin shell BEC, we characterize the long-range attraction between the vortex-antivortex pair and find the critical rotation speed that stabilizes the pair against energetically relaxing towards self-annihilation. In …
Pulsed Triple Frequency Modulation For Frequency Stabilization And Control Of Two Lasers To An Optical Cavity, William Williams, Maria Teresa Herd, E. C. Cook
Pulsed Triple Frequency Modulation For Frequency Stabilization And Control Of Two Lasers To An Optical Cavity, William Williams, Maria Teresa Herd, E. C. Cook
Physics: Faculty Publications
We present a method to stabilize two lasers to an optical cavity using pulsed triple frequency modulation. The setup allows simultaneous Pound–Drever–Hall stabilization, as well as independent frequency control, while removing interference terms that limit the frequency scan range and allowing for smaller modulation depths. A review of single, dual, and triple frequency modulation is also presented in addition to a discussion of how to effectively turn pulsed triple frequency modulation into independent dual frequency modulation for each laser. This method would increase the scan range to half the free spectral range.
Thermodynamics Of Rotating Quantum Matter In The Virial Expansion, Casey E. Berger, K. J. Morrell, J. E. Drut
Thermodynamics Of Rotating Quantum Matter In The Virial Expansion, Casey E. Berger, K. J. Morrell, J. E. Drut
Physics: Faculty Publications
We characterize the high-temperature thermodynamics of rotating bosons and fermions in two-dimensional (2D) and three-dimensional (3D) isotropic harmonic trapping potentials. We begin by calculating analytically the conventional virial coefficients bn for all n in the noninteracting case, as functions of the trapping and rotational frequencies. We also report on the virial coefficients for the angular momentum and associated moment of inertia. Using the bn coefficients, we analyze the deconfined limit (in which the angular frequency matches the trapping frequency) and derive explicitly the limiting form of the partition function, showing from the thermodynamic standpoint how both the 2D and 3D …
Resonant Two-Photon Spectroscopy Of The 2s3d 1D2 Level Of Neutral 9Be, Eryn C. Cook, Alisha D. Vira, William Williams
Resonant Two-Photon Spectroscopy Of The 2s3d 1D2 Level Of Neutral 9Be, Eryn C. Cook, Alisha D. Vira, William Williams
Physics: Faculty Publications
We report an absolute frequency measurement of the 2s3d 1 D2 state in neutral 9Be using two-photon spectroscopy with a resonant intermediate state. The absolute center-of-gravity energy is determined to be 64 428.40 321(55) cm−1, a factor of 180 more precise than the previous experimental measurement. We also confirm our previous result for the energy of the intermediate 2s2p 1 P1 level. Precision is limited by unresolved hyperfine structure and the complications of performing resonant two-photon spectroscopy on an atomic beam. A three-level rate-equation analysis is presented to explore, and minimize, systematic uncertainties arising from small deviations of the angle …