We study atom scattering from two colliding Bose-Einstein condensates using a position sensitive, time resolved, single detector. In analogy to quantum optics, the process can also be thought of as spontaneous, degenerate four-wave mixing de Broglie waves. find clear correlation between atoms with opposite momenta, demonstrating pair production in process. observe Hanbury Brown--Twiss for collinear which permits an independent measurement size source and thus spatial mode. The back-to-back...

An independent catalyst layer is used to improve the coking resistance of a Ni-based SOFC anode.

Amino-functionalized SBA-15 materials were synthesized by cocondensation of tetraethoxysilane (TEOS) with organosilane aminopropyltrimethoxysilane (APTMS) in a wide range molar ratios APTMS to TEOS the presence triblock copolymer P123 under acidic synthesis conditions. The effects F– periodically added into solution and concentration initial on textural properties functionalized investigated detail. addition can adversely affect mesostructure, whereas ordered mesostructure...

Quantum metrology with ultrahigh precision usually requires atoms prepared in an ultrastable environment well-defined quantum states. Thus, optical lattice clock systems deep potentials are used to trap ultracold atoms. However, decoherence, induced by Raman scattering and higher order light shifts, can significantly be reduced if atomic clocks realized shallow lattices. On the other hand, such lattices, tunneling among different sites cause additional dephasing strongly broadening of Rabi...

The dependence of the shift an optical bistability hysteresis curve on nonlinear phase induced by a controlling light is observed in four-level atomic system 87 Rb inside ring cavity. In process intensity coupling beam keeps constant and operated at near conditions coherent population trapping due to coherence. refractive absorptive chi3 nonlinearities enhanced coherence provide physical mechanism phenomena. Based effects, all-optical flip-flop storage pulse signals with low peak power...

We report the 87Sr optical lattice clock developed at National Time Service Center. achieved a closed-loop operation of based on atoms. The linewidth spin-polarized peak is 3.9 Hz with laser pulse length 300 ms, which corresponds to Fourier-limited 3 Hz. fitting in-loop error signal data shows that instability approximately , affected primarily by white noise. fractional frequency difference averages down for an averaging time 3000 s.

Abstract A photoacoustic spectroscopy sensor for nitrogen dioxide (NO 2 ) detection was presented based on a high‐power broadband blue diode laser emitting at 446 nm. An optical chopper replaced by transistor logic modulation signal generated the generator to reduce mechanical noise. The limit of NO system reached 46 ppt Allan variance analysis benefit reflection‐enhanced. continuous in atmosphere 48 h implemented collaboration with an adaptive Kalman filter lessening noise measurement....

We report our experimental observations of spatial shift and splitting four-wave mixing (FWM) signal beams induced by additional dressing laser beams. These effects are caused the enhanced cross-Kerr nonlinearity due to atomic coherence in a two-level system. The separation number split FWM can both be controlled intensity beam, Kerr nonlinearity, density. Theoretical results agree quite well with observations. Studies such beam very useful understanding soliton formation interactions,...

Abstract In the last decade, considerable advances have been made in investigation of dipolar quantum gases. Previous theoretical investigations a rotating binary Bose-Einstein condensate, where only one component possesses dipole moment, were mainly focused on two special orientations dipoles: perpendicular or parallel to plane motion. Here we study ground-state and rotational properties such system for an arbitrary orientation dipoles. We demonstrate vortex structures depend strongly...

We report a measurement of the radiative lifetime $5s5p\phantom{\rule{0.25em}{0ex}}{}^{3}{P}_{0}^{\mathrm{o}}$ metastable state in ${}^{87}\mathrm{Sr}$, which is coupled to $5{s}^{2}\phantom{\rule{0.25em}{0ex}}\phantom{\rule{0.2em}{0ex}}{}^{1}{S}_{0}$ ground via hyperfine-induced electric dipole transition. The determined be 151.4(48) s, good agreement with theoretical results. Our approach relies on accurate measurements laser intensity and free-space Rabi frequency, enabling any excited...

Abstract Dipolar Bosonic atoms confined in external potentials open up new avenues for quantum-state manipulation and will contribute to the design exploration of novel functional materials. Here we investigate ground-state rotational properties a rotating two-component dipolar Bose-Einstein condensate, which consists both bosonic with magnetic dipole moments aligned vertically condensate one without moments, concentrically coupled annular traps. For nonrotational case, it is found that...

We periodically modulate the lattice trapping potential of a $^{87}$Sr optical clock to Floquet engineer transition. In context atomic gases in lattices, engineering has been used shape dispersion and topology Bloch quasi-energy bands. Differently from these previous works manipulating external (spatial) quasi-energies, we target internal degrees freedom. spin quasi-energies measure their resonance profiles with Rabi spectroscopy. provide spectroscopic sensitivity each band by measuring...

We report an experiment in which optical pulses stored atomic system can be controllably released into two different photonic channels. By turning on the retrieve control at either 795 or $780\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ to read a four-level double $\ensuremath{\Lambda}$-type medium, we obtain probe pulse $780\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, respectively. These readout further separated spatially and directed propagation channels through grating. Such controlled release of...

Carbon deposition on a Ni-based anode is troublesome for the direct power generation from methane-based fuels using solid oxide fuel cell. In this paper, redox-stable double-perovskite Sr2MoFeO6-δ (SMFO) applied as an independent on-cell reforming catalyst over Ni-YSZ to improve coking resistance. The morphology, catalytic activity and electrochemical performance wet methane/coal-bed gas (CBG) are investigated. A supported cell with SMFO generates high output of 1.77 W·cm−2 exhibits...

We report a transportable one-dimensional optical lattice clock based on 87 Sr at the National Time Service Center. The apparatus consists of compact vacuum system and subsystems. with size 90 cm× 20 42 cm beam distributors are assembled double-layer breadboard. modularized subsystems integrated independent breadboards. By using 230 ms laser pulse, spin-polarized spectroscopy linewidth 4.8 Hz is obtained which close to 3.9 Fourier-limit linewidth. time interleaved self-comparison frequency...

We propose a method that enables precise determination of the number atoms in Dick-noise-free optical lattice clock, by effectively addressing quantum projection noise. Our approach relies on conducting stability measurements at three distinct parameter sets, allowing us to differentiate between noise, photon shot and technical Importantly, our accurate extraction atom number, even presence noise To validate effectiveness approach, we employ numerical simulations optimize modulation...