Extract the Degradation Information in Squeezed States with Machine Learning.

In order to leverage the full power of quantum noise squeezing with unavoidable decoherence, a complete understanding of the degradation in the purity of squeezed light is demanded. By implementing machine-learning architecture with a convolutional neural network, we illustrate a fast, robust, and precise quantum state tomography for continuous variables, through the experimentally measured data generated from the balanced homodyne detectors. Compared with the maximum likelihood estimation method, which suffers from time-consuming and overfitting problems, a well-trained machine fed with squeezed vacuum and squeezed thermal states can complete the task of reconstruction of the density matrix in less than one second. Moreover, the resulting fidelity remains as high as 0.99 even when the antisqueezing level is higher than 20 dB. Compared with the phase noise and loss mechanisms coupled from the environment and surrounding vacuum, experimentally, the degradation information is unveiled with machine learning for low and high noisy scenarios, i.e., with the antisqueezing levels at 12 dB and 18 dB, respectively. Our neural network enhanced quantum state tomography provides the metrics to give physical descriptions of every feature observed in the quantum state with a single scan measurement just by varying the local oscillator phase from 0 to 2π and paves a way of exploring large-scale quantum systems in real time.

Frequency-Dependent Squeezed Vacuum Source for Broadband Quantum Noise Reduction in Advanced Gravitational-Wave Detectors.

The astrophysical reach of current and future ground-based gravitational-wave detectors is mostly limited by quantum noise, induced by vacuum fluctuations entering the detector output port. The replacement of this ordinary vacuum field with a squeezed vacuum field has proven to be an effective strategy to mitigate such quantum noise and it is currently used in advanced detectors. However, current squeezing cannot improve the noise across the whole spectrum because of the Heisenberg uncertainty principle: when shot noise at high frequencies is reduced, radiation pressure at low frequencies is increased. A broadband quantum noise reduction is possible by using a more complex squeezing source, obtained by reflecting the squeezed vacuum off a Fabry-Perot cavity, known as filter cavity. Here we report the first demonstration of a frequency-dependent squeezed vacuum source able to reduce quantum noise of advanced gravitational-wave detectors in their whole observation bandwidth. The experiment uses a suspended 300-m-long filter cavity, similar to the one planned for KAGRA, Advanced Virgo, and Advanced LIGO, and capable of inducing a rotation of the squeezing ellipse below 100 Hz.

Absolute frequency measurement of molecular iodine hyperfine transitions at 647 nm.

We report absolute frequency measurements of molecular iodine P(46) 5-4 a1, a10, and a15 hyperfine transitions at 647 nm with a fiber-based frequency comb. The light source is based on a Littrow-type external-cavity diode laser. A frequency stability of 5×10-12 at a 200 s integration time is achieved when the light source is stabilized to the P(46) 5-4 a15 line. The pressure shift is determined to be -8.3(7) kHz/Pa. Our determination of the line centers reached a precision of 21 kHz. The light source can serve as a reference laser for lithium spectroscopy (2S→3P).

Watt-level single-frequency tapered amplifier laser using a narrowband interference filter.

We demonstrate a tunable external cavity tapered amplifier laser (ECTAL) using a narrowband interference filter as the wavelength discriminator. The laser is tunable over a wavelength range from 1006 to 1031 nm with an output power of ∼1 W. The amplified stimulated emission of the laser system is suppressed to better than 32 dB. The laser is applied to study the saturation spectroscopy on the R(39) 57-0 line of iodine molecule, which, to our best knowledge, is the first measurement of this line close to the dissociation limit. The linewidth of the a1 component is ∼2 MHz at the iodine vapor pressure of ∼11 Pa, and the pressure-broadening coefficient is ∼156 kHz/Pa. This laser system is also used for the injection seeding of a 1030 nm disk laser to perform hyperfine spectroscopy of muonic hydrogen. To reach a satisfactory condition for disk laser use, the ECTAL is successfully stabilized to the iodine Doppler-free spectroscopy of the P(26) 43-0 line near 515 nm, with continuous locking over 48 h.

Precise frequency measurements of iodine hyperfine transitions at 671 nm.

We report absolute frequency measurements on the a(1), a(10), and a(15) hyperfine components of the R(78) 4-6 line of (127)I(2). An external-cavity diode laser system at 671 nm is frequency-stabilized to the saturated absorption center obtained by modulation transfer spectroscopy in an iodine vapor cell. Its absolute frequency is measured by an optical frequency comb. The effect of pressure shift is investigated to obtain the absolute transition frequency at zero pressure. Our determination of the line centers reaches a precision of better than 40 kHz and will provide useful input for theoretical calculations. This frequency-stabilized laser can be used as a reference laser for the spectroscopy of lithium D lines.

Effect of a robotic prescription-filling system on pharmacy staff activities and prescription-filling time.

PURPOSE: The effects of using an automated prescription-filling system, the ScriptPro SP-200, in an independent pharmacy were evaluated. METHODS: The study was conducted at Punches Pharmacy Plus, an independent pharmacy located in Clare, Michigan. The study design was a preinstallation and postinstallation assessment of the ScriptPro SP-200 automated prescription-filling system. Videotaping and work sampling techniques were used to collect the preinstallation and postinstallation data of the ScriptPro SP-200. The use of the pharmacy staff and the time spent in direct and indirect prescription- filling activities, such as receiving, order entry, filling, inspecting, packaging, dispensing, phone calls, and inventory management, were measured and compared preinstallation and postinstallation. RESULTS: With the installation of automation, the percentage of time spent by the pharmacy staff significantly changed (p < 0.001). Meanwhile, there was a statistically significant difference in terms of the percentages of time spent on various activities between the preinstallation and postinstallation of automation (p < 0.001). Before installation of automation, the direct and indirect prescription-filling times used were 6.07 and 2.11 minutes, respectively, to fill one prescription. Analyses of the average time spent per prescription showed that the installation of automation could save nearly 0.22 minute per prescription, especially filling time per prescription-which was significantly decreased from 2.63 to 2.07 minutes with an average of 0.56 minute saved (p < 0.05). CONCLUSION: An automated system reduced prescription-filling time but required staffing adjustments to optimize the efficiency gained.