6,346 research outputs found
Electronic and phononic Raman scattering in detwinned YBaCuO and YCaBaCuO: s-wave admixture to the -wave order parameter
Inelastic light (Raman) scattering has been used to study electronic
excitations and phonon anomalies in detwinned, slightly overdoped
YBaCuO and moderately overdoped
YCaBaCuO single crystals. In both samples
modifications of the electronic pair-breaking peaks when interchanging the a-
and b-axis were observed. The lineshapes of several phonon modes involving
plane and apical oxygen vibrations exhibit pronounced anisotropies with respect
to the incident and scattered light field configurations. Based on a
theoretical model that takes both electronic and phononic contributions to the
Raman spectra into account, we attribute the anisotropy of the
superconductivity-induced changes in the phonon lineshapes to a small s-wave
admixture to the pair wave-function. Our theory allows us to
disentangle the electronic Raman signal from the phononic part and to identify
corresponding interference terms. We argue that the Raman spectra are
consistent with an s-wave admixture with an upper limit of 20 percent.Comment: accepted in Phys. Rev. B, 11 page
Characterization and assessment of PAH content in spent char to be used for soil amendment and carbon sequestration
Systematic study of Optical Feshbach Resonances in an ideal gas
Using a narrow intercombination line in alkaline earth atoms to mitigate
large inelastic losses, we explore the Optical Feshbach Resonance (OFR) effect
in an ultracold gas of bosonic Sr. A systematic measurement of three
resonances allows precise determinations of the OFR strength and scaling law,
in agreement with coupled-channels theory. Resonant enhancement of the complex
scattering length leads to thermalization mediated by elastic and inelastic
collisions in an otherwise ideal gas. OFR could be used to control atomic
interactions with high spatial and temporal resolution.Comment: Significant changes to text and figure presentation to improve
clarity. Extended supplementary material. 4 pages, 4 figures; includes
supplementary material 8 pages, 4 figures. Submitted to Physical Review
Letter
Isotope shifts of the (3s3p)P - (3s4s)S Mg I transitions
We report measurements of the isotope shifts of the (3s3p)P -
(3s4s)S Mg I transitions for the stable isotopes Mg (I=0),
Mg (I=5/2) and Mg (I=0). Furthermore the Mg S
hyperfine coefficient A(S) = (-321.6 1.5) MHz is extracted and
found to be in excellent agreement with state-of-the-art theoretical
predictions giving A(S) = -325 MHz and B(S)
MHz. Compared to previous measurements, the data presented in this work is
improved up to a factor of ten.Comment: 4 pages, 4 figures submitted to PR
Measurement of the Spin-forbidden Decay rate (3s3d)D (3s3p)P in Mg
We have measured the spin-forbidden decay rate from (3s3d)D
(3s3p)P in Mg atoms trapped in a magneto-optical trap. The
total decay rate, summing up both exit channels (3s3p)P and
(3s3p)P, yields (196 10) s in excellent agreement with
resent relativistic many-body calculations of [S.G. Porsev et al., Phys. Rev.
A. \textbf{64}, 012508 (2001)]. The characterization of this decay channel is
important as it may limit the performance of quantum optics experiments carried
out with this ladder system as well as two-photon cooling experiments currently
explored in several groups.Comment: 9 pages, 4 figure
Toward an Energy Efficient Language and Compiler for (Partially) Reversible Algorithms
We introduce a new programming language for expressing reversibility,
Energy-Efficient Language (Eel), geared toward algorithm design and
implementation. Eel is the first language to take advantage of a partially
reversible computation model, where programs can be composed of both reversible
and irreversible operations. In this model, irreversible operations cost energy
for every bit of information created or destroyed. To handle programs of
varying degrees of reversibility, Eel supports a log stack to automatically
trade energy costs for space costs, and introduces many powerful control logic
operators including protected conditional, general conditional, protected
loops, and general loops. In this paper, we present the design and compiler for
the three language levels of Eel along with an interpreter to simulate and
annotate incurred energy costs of a program.Comment: 17 pages, 0 additional figures, pre-print to be published in The 8th
Conference on Reversible Computing (RC2016
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