311 research outputs found

    Wage adjustment and productivity shocks

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    We study how workers’ wages respond to TFP-driven innovations in firms’labor productivity. Using unique data with highly reliable firm-level output prices and quantities in the manufacturing sector in Sweden, we are able to derive measures of physical (as opposed to revenue) TFP to instrument labor productivity in the wage equations. We find that the reaction of wages to sectoral labor productivity is almost three times larger than the response to pure idiosyncratic (firm-level) shocks, a result which crucially hinges on the use of physical TFP as an instrument. These results are all robust to a number of empirical specifications, including models accounting for selection on both the demand and supply side through worker-firm (match) fixed effects. Further results suggest that technological progress at the firm level has negligible effects on the firm-level composition of employees.Matched employer-employee data; sorting; wage; labor productivity; TFP

    Non-ergodic Intensity Correlation Functions for Blinking Nano Crystals

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    We investigate the non-ergodic properties of blinking nano-crystals using a stochastic approach. We calculate the distribution functions of the time averaged intensity correlation function and show that these distributions are not delta peaked on the ensemble average correlation function values; instead they are W or U shaped. Beyond blinking nano-crystals our results describe non-ergodicity in systems stochastically modeled using the Levy walk framework for anomalous diffusion, for example certain types of chaotic dynamics, currents in ion-channel, and single spin dynamics to name a few.Comment: 5 pages, 3 figure

    Time-resolved detection of relative intensity squeezed nanosecond pulses in a Rb87 vapor

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    We present theoretical and experimental results on the generation and detection of pulsed, relative-intensity squeezed light in a hot Rb87 vapor. The intensity noise correlations between a pulsed probe beam and its conjugate, generated through nearly-degenerate four-wave mixing in a double-lambda system, are studied numerically and measured experimentally via time-resolved balanced detection. We predict and observe about -1 dB of time-resolved relative intensity squeezing with 50 nanosecond pulses at 1 MHz repetition rate. (-1.34 dB corrected for loss).Comment: 11 pages, 9 figure

    Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots

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    Fluorescence blinking in nanocrystal quantum dots is known to exhibit power-law dynamics, and several different mechanisms have been proposed to explain this behavior. We have extended the measurement of quantum-dot blinking by characterizing fluctuations in the fluorescence of single dots over time scales from microseconds to seconds. The power spectral density of these fluctuations indicates a change in the power-law statistics that occurs at a time scale of several milliseconds, providing an important constraint on possible mechanisms for the blinking. In particular, the observations are consistent with the predictions of models wherein blinking is controlled by diffusion of the energies of electron or hole trap states

    Diffraction limited optics for single atom manipulation

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    We present an optical system designed to capture and observe a single neutral atom in an optical dipole trap, created by focussing a laser beam using a large numerical aperture N.A.=0.5 aspheric lens. We experimentally evaluate the performance of the optical system and show that it is diffraction limited over a broad spectral range (~ 200 nm) with a large transverse field (+/- 25 microns). The optical tweezer created at the focal point of the lens is able to trap single atoms of 87Rb and to detect them individually with a large collection efficiency. We measure the oscillation frequency of the atom in the dipole trap, and use this value as an independent determination of the waist of the optical tweezer. Finally, we produce with the same lens two dipole traps separated by 2.2 microns and show that the imaging system can resolve the two atoms.Comment: 8 pages, 9 figures; typos corrected and references adde

    Recent progress on the manipulation of single atoms in optical tweezers for quantum computing

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    This paper summarizes our recent progress towards using single rubidium atoms trapped in an optical tweezer to encode quantum information. We demonstrate single qubit rotations on this system and measure the coherence of the qubit. We move the quantum bit over distances of tens of microns and show that the coherence is reserved. We also transfer a qubit atom between two tweezers and show no loss of coherence. Finally, we describe our progress towards conditional entanglement of two atoms by photon emission and two-photon interferences.Comment: Proceedings of the ICOLS07 conferenc

    Generation of pulsed and continuous-wave squeezed light with 87^{87}Rb vapor

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    We present experimental studies on the generation of pulsed and continuous-wave squeezed vacuum via nonlinear rotation of the polarization ellipse in a 87^{87}Rb vapor. Squeezing is observed for a wide range of input powers and pump detunings on the D1 line, while only excess noise is present on the D2 line. The maximum continuous-wave squeezing observed is -1.4±0.1 1.4 \pm0.1 dB (-2.0 dB corrected for losses). We measure -1.1 dB squeezing at the resonance frequency of the 85^{85}Rb F=3FF=3 \to F' transition, which may allow the storage of squeezed light generated by 87^{87}Rb in a 85^{85}Rb quantum memory. Using a pulsed pump, pulsed squeezed light with -1 dB of squeezing for 200 ns pulse widths is observed at 1 MHz repetition rate.Comment: 9 pages, 5 figure

    Generation of ultrabright tunable polarization entanglement without spatial, spectral, or temporal constraints

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    The need for spatial and spectral filtering in the generation of polarization entanglement is eliminated by combining two coherently-driven type-II spontaneous parametric downconverters. The resulting ultrabright source emits photon pairs that are polarization entangled over the entire spatial cone and spectrum of emission. We detect a flux of \sim12 000 polarization-entangled pairs/s per mW of pump power at 90% quantum-interference visibility, and the source can be temperature tuned for 5 nm around frequency degeneracy. The output state is actively controlled by precisely adjusting the relative phase of the two coherent pumps.Comment: 10 pages, 5 figure

    Non-Local Control of Single Surface Plasmon

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    Quantum entanglement is a stunning consequence of the superposition principle. This universal property of quantum systems has been intensively explored with photons, atoms, ions and electrons. Collective excitations such as surface plasmons exhibit quantum behaviors. For the first time, we report an experimental evidence of non-local control of single plasmon interferences through entanglement of a single plasmon with a single photon. We achieved photon-plasmon entanglement by converting one photon of an entangled photon pair into a surface plasmon. The plasmon is tested onto a plasmonic platform in a Mach-Zehnder interferometer. A projective measurement on the polarization of the photon allows the non-local control of the interference state of the plasmon. Entanglement between particles of various natures paves the way to the design of hybrid systems in quantum information networks.Comment: 6 pages, 3 figure
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