Feedback-free optical cavity with self-resonating mechanism

We demonstrated the operation of a high finesse optical cavity without utilizing an active feedback system to stabilize the resonance. The effective finesse, which is a finesse including the overall system performance, of the cavity was measured to be $394,000 \pm 10,000$, and the laser power stored in the cavity was $2.52 \pm 0.13$ kW, which is approximately 187,000 times greater than the incident power to the cavity. The stored power was stabilized with a fluctuation of $1.7 \%$, and we confirmed continuous cavity operation for more than two hours. This result has the potential to trigger an innovative evolution for applications that use optical resonant cavities such as compact photon sources with laser-Compton scattering or cavity enhanced absorption spectroscopy.Comment: 5 pages, 7 figure

Dark Energy Survey Year 1 Results: Tomographic cross-correlations between Dark Energy Survey galaxies and CMB lensing from South Pole Telescope + Planck

We measure the cross-correlation between REDMAGIC galaxies selected from the Dark Energy Survey (DES) year 1 data and gravitational lensing of the cosmic microwave background (CMB) reconstructed from South Pole Telescope (SPT) and Planck data over 1289  deg^2. When combining measurements across multiple galaxy redshift bins spanning the redshift range of 0.15 < z < 0.90, we reject the hypothesis of no correlation at 19.9σ significance. When removing small-scale data points where thermal Sunyaev-Zel’dovich signal and nonlinear galaxy bias could potentially bias our results, the detection significance is reduced to 9.9σ. We perform a joint analysis of galaxy-CMB lensing cross-correlations and galaxy clustering to constrain cosmology, finding Ω_m = 0.276^(+0.029)_(−0.030_ and S_8 = σ_8√Ω_m/0.3 = 0.800^(+0.090)_(−0.094). We also perform two alternate analyses aimed at constraining only the growth rate of cosmic structure as a function of redshift, finding consistency with predictions from the concordance ΛCDM model. The measurements presented here are part of a joint cosmological analysis that combines galaxy clustering, galaxy lensing and CMB lensing using data from DES, SPT and Planck

Dark Energy Survey Year 1 Results: Cross-correlation between Dark Energy Survey Y1 galaxy weak lensing and South Pole Telescope+Planck CMB weak lensing

We cross-correlate galaxy weak lensing measurements from the Dark Energy Survey (DES) year-one data with a cosmic microwave background (CMB) weak lensing map derived from South Pole Telescope (SPT) and Planck data, with an effective overlapping area of 1289  deg^2. With the combined measurements from four source galaxy redshift bins, we obtain a detection significance of 5.8σ. We fit the amplitude of the correlation functions while fixing the cosmological parameters to a fiducial ΛCDMmodel, finding A=0.99±0.17. We additionally use the correlation function measurements to constrain shear calibration bias, obtaining constraints that are consistent with previous DES analyses. Finally, when performing a cosmological analysis under the ΛCDM model, we obtain the marginalized constraints of Ω_m=0.261^(+0.070)_(−0.051) and S_8≡σ_8√Ω_m/0.3=0.660^(+0.085)_(−0.100). These measurements are used in a companion work that presents cosmological constraints from the joint analysis of two-point functions among galaxies, galaxy shears, and CMB lensing using DES, SPT, and Planck data

A 2500 deg^2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg^2 SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader ℓ coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential C^(φ φ)_L, and compare it to the theoretical prediction for a ΛCDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95^(+0.06)_(-0.06)(stat.)^(+0.01)_(-0.01)(sys). The null hypothesis of no lensing is rejected at a significance of 24σ. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, C^(φG)_L, between the SPT+Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit C^(φG)_L to a power law of the form p_L = s(L/L_0)^(-b) with a, L_0, and b fixed, and find η^( φG) = C^( φG)_L/P_L = 0.94^(+0.04)_(-0.04), which is marginally lower, but in good agreement with η^( φG) = 1.00^(+0.02)_(-0.01), the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISEgalaxies over ~67% of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg^2 field