We accurately evaluate the blackbody-radiation shift in a171 Yb optical lattice clock by utilizing temperature measurement and numerical simulation. In this work. three main radiation sources are considered for the blackbody-radiation shift, including the heated atomic oven, the warm vacuum chamber, and the room-temperature vacuum windows. The temperatures on the outer surface of the vacuum chamber are measured during the clock operation period by utilizing seven calibrated temperature sensors. Then we infer the temperature distribution inside the vacuum chamber by numerical simulation according to the measured temperatures. Furthermore, we simulate the temperature variation around the cold atoms while the environmental temperature is fluctuating. Finally, we obtain that the total blackbody-radiation shift is -1.289(7)Hz with an uncertainty of 1.25×10^(-17) for our ^(171)Yb optical lattice clock. The presented method is quite suitable for accurately evaluating the blackbody-radiation shift of the optical lattice clock in the case of lacking the sensors inside the vacuum chamber.
Using two tripartite Greenberger–Horne–Zeilinger(GHZ)states as the shared channels,we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state.By unitary matrix decomposition procedure,we first construct the quantum logic circuit of the deterministic joint remote state preparation protocol.Then,we analytically derive the fidelity and the average fidelity for the deterministic joint remote preparation of an arbitrary twoqubit state and of four types of special two-qubit states under the influence of the Pauli noises.It is found that the fidelity depends on the noise types,the qubit-environment coupling strength,and the state to be remotely prepared.Moreover,even if the two GHZ channels are subject to the same environmental noises,the average fidelities for remotely preparing different two-qubit states display different time evolution behaviors.The remote preparation of the identical two-qubit states also shows that the average fidelities affected by different noisy environments exhibit different evolution actions.
High power second harmonic generation(SHG) in MgO-doped LiNbO3 waveguides is investigated using a three-dimensional(3D) coupled thermo-optical model.Simulations performed for a 1111.6-nm fundamental laser show the in?uence of the absorptions and the thermally induced dephasing on the conversion efficiencies of the different waveguides.The onset of the thermally induced dephasing effect for each waveguide is also indicated.As a result of high light intensity in the waveguide,nonlinear absorptions are identified as the possible main factors in efficiency losses in specific cases.
We develop a permanent-magnet Zeeman slower with adjustable magnets along the longitudinal and radial directions.Produced by four arrays of cylindrical magnets, the longitudinal magnetic field in the slower is tunable if relevant parameters vary, for example, laser detuning or intensity. The proposed Zeeman slower can be reconfigured for Sr atoms. Additionally,we demonstrate that the residual magnetic field produced by the permanent magnets in the magneto-optical trap region can be as small as 0.5 Gs.
The optical atomic clocks have the potential to transform global timekeeping,relying on the state-of-the-art accuracy and stability,and greatly improve the measurement precision for a wide range of scientific and technological applications.Herein we report on the development of the optical clock based on 171Yb atoms confined in an optical lattice.A minimum width of 1.92-Hz Rabi spectra has been obtained with a new 578-nm clock interrogation laser.The in-loop fractional instability of the 171Yb clock reaches 9.1×10-18 after an averaging over a time of 2.0×104 s.By synchronous comparison between two clocks,we demonstrate that our 171Yb optical lattice clock achieves a fractional instability of 4.60×10-16/√τ.
We investigate the characteristics of three kinds of quantum correlations, measured by pairwise quantum discord(QD), geometric measure of quantum discord(GMQD), and measurement-induced disturbance(MID), in the systems of three- and four-dipole arrays. The influence of the temperature on the three quantum correlations and entanglement of the systems is also analyzed numerically. It is found that novel quantum correlation switches called QD, GMQD, and MID respectively can be constructed with the qubits consisting of electric dipoles coupled by the dipole–dipole interaction and oriented along or against the external electric field. Moreover, with the increase of temperature, QD, GMQD, and MID are more robust than entanglement against the thermal environment. It is also found that for each dipole pair of the three- and four-dipole arrangements, the MID is always the largest and the GMQD the smallest.
