Leveraging the unrivalled performance of optical clocks as key tools for geo-science, for astronomy and for fundamental physics beyond the standard model requires comparing the frequency of distant ...optical clocks faithfully. Here, we report on the comparison and agreement of two strontium optical clocks at an uncertainty of 5 × 10(-17) via a newly established phase-coherent frequency link connecting Paris and Braunschweig using 1,415 km of telecom fibre. The remote comparison is limited only by the instability and uncertainty of the strontium lattice clocks themselves, with negligible contributions from the optical frequency transfer. A fractional precision of 3 × 10(-17) is reached after only 1,000 s averaging time, which is already 10 times better and more than four orders of magnitude faster than any previous long-distance clock comparison. The capability of performing high resolution international clock comparisons paves the way for a redefinition of the unit of time and an all-optical dissemination of the SI-second.
We report the first demonstration of a long-distance ultra-stable frequency dissemination in the microwave range. A 9.15-GHz signal is transferred through an 86-km urban optical link with a ...fractional frequency instability of 1.3×10
−15
at 1-s integration time and below 10
−18
at one day. The optical link phase noise compensation is performed with a round-trip method. To achieve such a result we implement light polarisation scrambling and dispersion compensation. This link outperforms all the previous radio-frequency links and compares well with recently demonstrated full optical links.
A Watt-level continuous and single frequency blue laser at 461 nm is obtained by frequency-doubling an amplified diode laser operating at 922 nm via a LBO crystal in a resonant Fabry-Pérot cavity. We ...achieved a best optical conversion efficiency equal to 87% with more than 1 W output power in the blue, and limited by the available input power. The frequency-converted beam is characterized in terms of long term power stability, residual intensity noise, and geometrical shape. The blue beam has a linewidth of the order of 1 MHz, and we used it to magneto-optically trap
88
Sr atoms on the 5s
2
1
S
0
– 5s5p
1
P
1
transition. The low-finesse, linear-cavity doubling system is very robust, maintains the lock for several days, and is compatible with a tenfold increase of the power levels which could be obtained with fully-fibered amplifiers and large mode area fibers.
Introduction
It is proven that high levels of disgust contribute to implementing protective behaviors. Investigators also discovered that the emotion of disgust plays a central role in determining ...anxiety related to the contraction of COVID-19. Few data are available about the role of the contamination disgust, a specific disgust domain, in this relationship.
Objectives
The effect of contamination disgust on COVID-19-related anxiety was investigated.
Methods
295 healthy subjects were enrolled through an online survey. They completed Disgust Scale-Revised (DS-R) and were asked to estimate their levels of Covid-19-related anxiety in 12 proposed situations. A total score was then calculated. An ANOVA model having Covid-19-related anxiety total score as dependent variable, and DS-R contamination disgust, age, and sex as predictors was estimated.
Results
The overall model was significant (F(3,291)=6.402, p<0.001) and explained 6.2% of total Covid-19 anxiety variance (R
2
=0.062). The effect of DS-R contamination disgust on Covid-19-related anxiety was positive, significant (B=0.974, t(291)=3.227, p=0.001) and explained 3.5% of Covid-19-related anxiety variance (partial η
2
=0.035). A significant effect of sex was detected
(F(1,291)=4.919, p=0.027), with females having higher Covid-19-related anxiety than males, while no effect was detected for age (B=-0.024, t(291)=-0.884, p=0.377).
Conclusions
The presented data provide preliminary evidence for an effect of contamination disgust on Covid-19-related anxiety.
Disclosure
No significant relationships.
We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-SYRTE (Laboratoire ...National de métrologie et d'Essais-SYstème de Références Temps-Espace) in Paris (France) with two at PTB (Physikalisch-Technische Bundesanstalt) in Braunschweig (Germany). For a long time, these PFSs have been major contributors to accuracy of the International Atomic Time (TAI), with stated accuracies of around 3×10−16. They have also been the references for a number of absolute measurements of clock transition frequencies in various optical frequency standards in view of a future redefinition of the second. The phase coherent optical frequency transfer via a stabilized telecom fiber link enables far better resolution than any other means of frequency transfer based on satellite links. The agreement for each pair of distant fountains compared is well within the combined uncertainty of a few 10−16 for all the comparisons, which fully supports the stated PFSs' uncertainties. The comparison also includes a rubidium fountain frequency standard participating in the steering of TAI and enables a new absolute determination of the 87Rb ground state hyperfine transition frequency with an uncertainty of 3.1×10−16. This paper is dedicated to the memory of André Clairon, who passed away on 24 December 2015, for his pioneering and long-lasting efforts in atomic fountains. He also pioneered optical links from as early as 1997.
Progress in realizing the SI second had multiple technological impacts and enabled further constraint of theoretical models in fundamental physics. Caesium microwave fountains, realizing best the ...second according to its current definition with a relative uncertainty of 2-4 × 10(-16), have already been overtaken by atomic clocks referenced to an optical transition, which are both more stable and more accurate. Here we present an important step in the direction of a possible new definition of the second. Our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.5 × 10(-16). Their comparison with three independent caesium fountains shows a degree of accuracy now only limited by the best realizations of the microwave-defined second, at the level of 3.1 × 10(-16).
We report the measurement of the frequency noise power spectral density of a quantum cascade laser emitting at 2.5THz. The technique is based on heterodyning the laser emission frequency with a ...harmonic of the repetition rate of a near-infrared laser comb. This generates a beatnote in the radio frequency range that is demodulated using a tracking oscillator allowing measurement of the frequency noise. We find that the latter is strongly affected by the level of optical feedback, and obtain an intrinsic linewidth of ~230Hz, for an output power of 2mW.
We report the main features and performances of a prototype of an ultra-stable cavity designed and realized by industry for space applications with the aim of space missions. The cavity is a 100 mm ...long cylinder rigidly held at its midplane by a engineered mechanical interface providing an efficient decoupling from thermal and vibration perturbations. Intensive finite element modeling was performed in order to optimize thermal and vibration sensitivities while getting a high fundamental resonance frequency. The system was designed to be transportable, acceleration tolerant (up to several g) and temperature range compliant -33°C ; 73°C. Thermal isolation is ensured by gold coated Aluminum shields inside a stainless steel enclosure for vacuum. The axial vibration sensitivity was evaluated at (4 ± 0.5) × 10(-11)/(m.s(-2)), while the transverse one is < 1 × 10(-11)/(m.s(-2)). The fractional frequency instability is </~ 1×10(-15) from 0.1 to a few seconds and reaches 5-6×10(-16) at 1s.
Introduction
Attachment style is defined by the American Psychological Association as “the characteristic way people relate to others in the context of intimate relationships”. Four attachment styles ...have been described: secure, fearful, preoccupied, and dismissing. While the effect of attachment style on psychotherapy was widely investigated, few studies have investigated its role in determining beliefs about medicines in patients with Major Depressive Disorder (MDD).
Objectives
This study aimed to investigate the relationship between preoccupied attachment style and beliefs about medicines in patients with MDD.
Methods
27 patients admitted in the Psychiatric Unit of Careggi with diagnosis of MDD were enrolled. Working Alliance Inventory - patient version (WAI-P), Relationship Style Questionnaire (RSQ) and Beliefs about Medicines Questionnaire (BMQ) were administered. An ANCOVA model having BMQ total score as dependent variable and age, sex, RSQ preoccupied attachment subscale and WAI-P task subscale as predictors was considered. WAI-P task was intended to assess the role of agreement on therapeutic choices.
Results
The overall model was significant (F(4,22)=9,571, P<0.001) and explained 66.8% of BMQ total score variance (R
2
=0.668). Both RSQ preoccupied attachment subscale (B=3.331, t(22)=3.907, p=0.001) and WAI-P task subscale (B=0.238, t(22)=4.565, p<0.001) showed a positive correlation with BMQ total scores. RSQ preoccupied attachment subscale explained 44.6% of variance of BMQ total scores (partial η
2
=0.446), WAI-P task explained 52.3% of variance of BMQ total scores (partial η
2
= 0.523). Age (B=0.059, t(22)=1.588, p=0.129) and sex (F(1,22)=0.035, p=0.854) had no significant effect.
Conclusions
These preliminary data suggest a possible influence of preoccupied attachment style on beliefs about medicines in patients with MDD.
Disclosure
No significant relationships.
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