A quantum enhanced search for dark matter axions.

The manipulation of quantum states of light1 holds the potential to enhance searches for fundamental physics. Only recently has the maturation of quantum squeezing technology coincided with the emergence of fundamental physics searches that are limited by quantum uncertainty2,3. In particular, the quantum chromodynamics axion provides a possible solution to two of the greatest outstanding problems in fundamental physics: the strong-CP (charge-parity) problem of quantum chromodynamics4 and the unknown nature of dark matter5-7. In dark matter axion searches, quantum uncertainty manifests as a fundamental noise source, limiting the measurement of the quadrature observables used for detection. Few dark matter searches have approached this limit3,8, and until now none has exceeded it. Here we use vacuum squeezing to circumvent the quantum limit in a search for dark matter. By preparing a microwave-frequency electromagnetic field in a squeezed state and near-noiselessly reading out only the squeezed quadrature9, we double the search rate for axions over a mass range favoured by some recent theoretical projections10,11. We find no evidence of dark matter within the axion rest energy windows of 16.96-17.12 and 17.14-17.28 microelectronvolts. Breaking through the quantum limit invites an era of fundamental physics searches in which noise reduction techniques yield unbounded benefit compared with the diminishing returns of approaching the quantum limit.

First Results from a Microwave Cavity Axion Search at 24 µeV.

We report on the first results from a new microwave cavity search for dark matter axions with masses above 20 µeV. We exclude axion models with two-photon coupling g_{aγγ}≳2×10^{-14} GeV^{-1} over the range 23.55

Effect of preoperative pregabalin on post-caesarean delivery analgesia: a dose-response study.

INTRODUCTION: We hypothesised that preoperative administration of a single-dose of pregabalin would be associated with lower morphine consumption after uncomplicated caesarean delivery. METHODS: After Institutional Ethics Committee approval, 135 parturients scheduled for elective caesarean delivery under spinal anaesthesia were randomly allocated to receive either placebo, or oral pregabalin 150mg or 300mg, one hour before induction of anaesthesia. Maternal cumulative morphine requirement at 24h, pain scores, sedation scores, nausea and vomiting, pruritus, pregabalin-related adverse effects, Apgar scores, Neurologic and Adaptive Capacity scores and umbilical cord acid-base status were recorded. RESULTS: Compared with placebo or pregabalin 150mg, the use of a preoperative dose of pregabalin 300mg resulted in significantly lower cumulative morphine consumption at 24h (mean dose: placebo 12.9mg [95% CI 11.6 to 14.2]; pregabalin 150mg 11.9mg; [95% CI 10.7 to 13.1]; pregabalin 300mg 6mg [95% CI 5.4 to 7.3]; P<0.001). Pregabalin 300mg resulted in lower pain scores at 4h and 6h after delivery (P<0.001), and fewer instances of nausea, vomiting and pruritus (P<0.009). Dizziness and abnormal vision were observed most frequently in the pregabalin 300mg group (P<0.05 and P<0.009, respectively). The three groups were similar in terms of maternal sedation, Apgar scores, Neurologic and Adaptive Capacity scores and umbilical cord acid-base status. Three babies in the pregabalin 300mg group (6.7%) experienced short-term poor latching-on for breastfeeding. CONCLUSION: In our study, preoperative administration of pregabalin 300mg reduced postoperative morphine consumption and early postoperative pain in parturients undergoing elective caesarean delivery, although maternal side effects were more common.

Search for low-mass weakly interacting massive particles with SuperCDMS.

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30 GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42) cm(2) at 8 GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6 GeV/c(2).