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Slepian, Zachary,Eisenstein, Daniel J.,Brownstein, Joel R.,Chuang, Chia-Hsun,Gil-Marí,n, Hé,ctor,Ho, Shirley,Kitaura, Francisco-Shu,Percival, Will J.,Ross, Ashley J.,Rossi, Graziano,Seo, H Oxford University Press 2017 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.469 No.2
<P>We present the large-scale three-point correlation function (3PCF) of the Sloan Digital Sky Survey DR12 Constant stellar Mass (CMASS) sample of 777 202 Luminous Red Galaxies, the largest-ever sample used for a 3PCF or bispectrum measurement. We make the first high-significance (4.5 sigma) detection of baryon acoustic oscillations (BAO) in the 3PCF. Using these acoustic features in the 3PCF as a standard ruler, we measure the distance to z = 0.57 to 1.7 per cent precision (statistical plus systematic). We find DV = 2024 +/- 29 Mpc (stat) +/- 20 Mpc (sys) for our fiducial cosmology (consistent with Planck 2015) and bias model. This measurement extends the use of the BAO technique from the two-point correlation function (2PCF) and power spectrum to the 3PCF and opens an avenue for deriving additional cosmological distance information from future large-scale structure redshift surveys such as DESI. Our measured distance scale from the 3PCF is fairly independent from that derived from the pre-reconstruction 2PCF and is equivalent to increasing the length of BOSS by roughly 10 per cent; reconstruction appears to lower the independence of the distance measurements. Fitting a model including tidal tensor bias yields a moderate-significance (2.6 sigma) detection of this bias with a value in agreement with the prediction from local Lagrangian biasing.</P>
Cosmological constraints from the SDSS luminous red galaxies
Tegmark, Max,Eisenstein, Daniel J.,Strauss, Michael A.,Weinberg, David H.,Blanton, Michael R.,Frieman, Joshua A.,Fukugita, Masataka,Gunn, James E.,Hamilton, Andrew J. S.,Knapp, Gillian R.,Nichol, Robe American Physical Society 2006 PHYSICAL REVIEW D - Vol.74 No.12
Jungho Kim,Meuer, C,Bimberg, D,Eisenstein, G IEEE 2010 IEEE journal of quantum electronics Vol.46 No.11
<P>We numerically investigate the effect of inhomogeneous broadening caused by quantum-dot (QD) size fluctuations on the gain and phase recovery of QD semiconductor optical amplifiers (SOAs). We establish 1088 coupled rate equations to simulate the carrier dynamics of the inhomogeneously broadened QD ensembles as inhomogeneous broadening increases. When all the QD ensembles are identical and inhomogeneous broadening becomes zero, eight coupled rate equations are solved for the homogeneous QDs. The gain and phase recovery responses are calculated when an ultrashort pump pulse is injected into a QD SOA. As the inhomogeneous broadening increases, the slow component of the phase recovery at the QD ground state increases due to the enlarged contribution from the slow phase recovery of carrier reservoirs such as the QD excited states. By separately calculating the gain and phase recovery responses of the homogeneous QDs with different sizes, we identify how increasing inhomogeneous broadening affects the enlarged slow phase recovery components from carrier reservoirs. We also demonstrate that the effect of inhomogeneous broadening on the temporal variation of the α-factor is more significant compared to the injection pump power.</P>
Kim, Jungho,Meuer, Christian,Bimberg, Dieter,Eisenstein, Gadi Institute of Physics 2011 Semiconductor science and technology Vol.26 No.1
<P>We numerically investigate the influence of the pump-probe wavelength on the gain and phase recovery dynamics of quantum-dot (QD) semiconductor optical amplifiers (SOAs). The temporal variations of the gain and phase recovery response are calculated at various pump-probe wavelengths, covering the emission wavelength of both the QD ground and excited states. The gain recovery becomes faster at the longer pump-probe wavelength due to the enlarged carrier escape time. The initial phase change turns from a negative to a positive value as the pump-probe wavelength becomes smaller, which is determined by the spectral position of the pump-probe wavelength in reference to the Gaussian-shaped inhomogeneous broadening. The calculated results agree with the previous experimental results measured by other experimental groups.</P>
Jungho Kim,Meuer, C.,Bimberg, D.,Eisenstein, G. IEEE 2010 IEEE journal of quantum electronics Vol.46 No.3
<P>We numerically investigate the gain and phase recovery dynamics of quantum-dot (QD) semiconductor optical amplifiers (SOAs) by simultaneous consideration of the temporal and spectral variations. We solve 1088 coupled rate equations to simulate the carrier recovery dynamics of the inhomogeneously broadened QD ensemble, where QD electron and hole states are considered separately. The gain and phase recovery responses induced by an ultrafast pump pulse are calculated by considering different carrier relaxation time constants and spectral line shape functions involved in the successive carrier recovery process. The interband transition is assumed to have a Lorentzian line shape function and the intraband free-carrier absorption is described by the Drude model. We demonstrate that the actual behavior of the gain and phase recovery in QD SOAs can be clearly understood by simultaneously considering the temporal and spectral behavior of the gain and phase recovery responses, which are visualized by means of plots in the time and wavelength domains. We identify how the respective QD state-the ground state, the excited state, and an upper state-and quantum-well carrier reservoirs contribute to the gain and phase recovery of QD SOAs both temporally and spectrally.</P>
Meuer, C.,Jungho Kim,Laemmlin, M.,Liebich, S.,Eisenstein, G.,Bonk, R.,Vallaitis, T.,Leuthold, J.,Kovsh, A.,Krestnikov, I.,Bimberg, D. IEEE 2009 IEEE journal of selected topics in quantum electro Vol.15 No.3
<P>Wavelength conversion using cross-gain modulation (XGM) in quantum-dot (QD) semiconductor optical amplifiers (SOAs) is investigated. Small-signal measurements reveal that the XGM bandwidth as well as the conversion efficiency strongly depends on the bias current. Thus, it is possible to tune the XGM by increasing the current from a low efficiency with a 10-GHz bandwidth to a very efficient one with bandwidths well exceeding 40 GHz. Two different saturation mechanisms are responsible for this pronounced influence of the bias current: 1) total carrier depletion that leads to a slow broadband cross-gain saturation and 2) spectral hole burning that causes spectrally narrow-band high-speed XGM. With increasing current, the saturation by depleting the carrier reservoir, which feeds the QDs, is minimized, and therefore, spectral hole burning becomes more dominant. Large-signal wavelength conversion experiments using 50 ps pulses indicate that efficient high-speed XGM is feasible for pump and probe signal detuning up to 10 nm. With increasing detuning, larger pulse broadening and a decreasing efficiency are observed, consistent with the small-signal results. The results on the QD SOAs are compared to conventional quantum-well devices.</P>