Trap-integrated fluorescence detection with silicon photomultipliers for sympathetic laser cooling in a cryogenic Penning trap.

We present a fluorescence-detection system for laser-cooled 9Be+ ions based on silicon photomultipliers (SiPMs) operated at 4 K and integrated into our cryogenic 1.9 T multi-Penning-trap system. Our approach enables fluorescence detection in a hermetically sealed cryogenic Penning-trap chamber with limited optical access, where state-of-the-art detection using a telescope and photomultipliers at room temperature would be extremely difficult. We characterize the properties of the SiPM in a cryocooler at 4 K, where we measure a dark count rate below 1 s-1 and a detection efficiency of 2.5(3)%. We further discuss the design of our cryogenic fluorescence-detection trap and analyze the performance of our detection system by fluorescence spectroscopy of 9Be+ ion clouds during several runs of our sympathetic laser-cooling experiment.

BASE-STEP: A transportable antiproton reservoir for fundamental interaction studies.

Currently, the world's only source of low-energy antiprotons is the AD/ELENA facility located at CERN. To date, all precision measurements on single antiprotons have been conducted at this facility and provide stringent tests of fundamental interactions and their symmetries. However, magnetic field fluctuations from the facility operation limit the precision of upcoming measurements. To overcome this limitation, we have designed the transportable antiproton trap system BASE-STEP to relocate antiprotons to laboratories with a calm magnetic environment. We anticipate that the transportable antiproton trap will facilitate enhanced tests of charge, parity, and time-reversal invariance with antiprotons and provide new experimental possibilities of using transported antiprotons and other accelerator-produced exotic ions. We present here the technical design of the transportable trap system. This includes the transportable superconducting magnet, the cryogenic inlay consisting of the trap stack and detection systems, and the differential pumping section to suppress the residual gas flow into the cryogenic trap chamber.

A high-Q superconducting toroidal medium frequency detection system with a capacitively adjustable frequency range >180 kHz.

We describe a newly developed polytetrafluoroethylene/copper capacitor driven by a cryogenic piezoelectric slip-stick stage and demonstrate with the chosen layout cryogenic capacitance tuning of ≈60 pF at ≈10 pF background capacitance. Connected to a highly sensitive superconducting toroidal LC circuit, we demonstrate tuning of the resonant frequency between 345 and 685 kHz, at quality factors Q > 100 000. Connected to a cryogenic ultra low noise amplifier, a frequency tuning range between 520 and 710 kHz is reached, while quality factors Q > 86 000 are achieved. This new device can be used as a versatile image current detector in high-precision Penning-trap experiments or as an LC-circuit-based haloscope detector to search for the conversion of axion-like dark matter to radio-frequency photons. This new development increases the sensitive detection bandwidth of our axion haloscope by a factor of ≈1000.

A 16-parts-per-trillion measurement of the antiproton-to-proton charge-mass ratio.

The standard model of particle physics is both incredibly successful and glaringly incomplete. Among the questions left open is the striking imbalance of matter and antimatter in the observable universe1, which inspires experiments to compare the fundamental properties of matter/antimatter conjugates with high precision2-5. Our experiments deal with direct investigations of the fundamental properties of protons and antiprotons, performing spectroscopy in advanced cryogenic Penning trap systems6. For instance, we previously compared the proton/antiproton magnetic moments with 1.5 parts per billion fractional precision7,8, which improved upon previous best measurements9 by a factor of greater than 3,000. Here we report on a new comparison of the proton/antiproton charge-to-mass ratios with a fractional uncertainty of 16 parts per trillion. Our result is based on the combination of four independent long-term studies, recorded in a total time span of 1.5 years. We use different measurement methods and experimental set-ups incorporating different systematic effects. The final result, [Formula: see text], is consistent with the fundamental charge-parity-time reversal invariance, and improves the precision of our previous best measurement6 by a factor of 4.3. The measurement tests the standard model at an energy scale of 1.96 × 10-27 gigaelectronvolts (confidence level 0.68), and improves ten coefficients of the standard model extension10. Our cyclotron clock study also constrains hypothetical interactions mediating violations of the clock weak equivalence principle (WEPcc) for antimatter to less than 1.8 × 10-7, and enables the first differential test of the WEPcc using antiprotons11. From this interpretation we constrain the differential WEPcc-violating coefficient to less than 0.030.

Sympathetic cooling of a trapped proton mediated by an LC circuit.

Efficient cooling of trapped charged particles is essential to many fundamental physics experiments1,2, to high-precision metrology3,4 and to quantum technology5,6. Until now, sympathetic cooling has required close-range Coulomb interactions7,8, but there has been a sustained desire to bring laser-cooling techniques to particles in macroscopically separated traps5,9,10, extending quantum control techniques to previously inaccessible particles such as highly charged ions, molecular ions and antimatter. Here we demonstrate sympathetic cooling of a single proton using laser-cooled Be+ ions in spatially separated Penning traps. The traps are connected by a superconducting LC circuit that enables energy exchange over a distance of 9 cm. We also demonstrate the cooling of a resonant mode of a macroscopic LC circuit with laser-cooled ions and sympathetic cooling of an individually trapped proton, reaching temperatures far below the environmental temperature. Notably, as this technique uses only image-current interactions, it can be easily applied to an experiment with antiprotons1, facilitating improved precision in matter-antimatter comparisons11 and dark matter searches12,13.

Direct limits on the interaction of antiprotons with axion-like dark matter.

Astrophysical observations indicate that there is roughly five times more dark matter in the Universe than ordinary baryonic matter1, and an even larger amount of the Universe's energy content is attributed to dark energy2. However, the microscopic properties of these dark components remain unknown. Moreover, even ordinary matter-which accounts for five per cent of the energy density of the Universe-has yet to be understood, given that the standard model of particle physics lacks any consistent explanation for the predominance of matter over antimatter3. Here we present a direct search for interactions of antimatter with dark matter and place direct constraints on the interaction of ultralight axion-like particles (dark-matter candidates) with antiprotons. If antiprotons have a stronger coupling to these particles than protons do, such a matter-antimatter asymmetric coupling could provide a link between dark matter and the baryon asymmetry in the Universe. We analyse spin-flip resonance data in the frequency domain acquired with a single antiproton in a Penning trap4 to search for spin-precession effects from ultralight axions, which have a characteristic frequency governed by the mass of the underlying particle. Our analysis constrains the axion-antiproton interaction parameter to values greater than 0.1 to 0.6 gigaelectronvolts in the mass range from 2 × 10-23 to 4 × 10-17 electronvolts, improving the sensitivity by up to five orders of magnitude compared with astrophysical antiproton bounds. In addition, we derive limits on six combinations of previously unconstrained Lorentz- and CPT-violating terms of the non-minimal standard model extension5.

Measurement of Ultralow Heating Rates of a Single Antiproton in a Cryogenic Penning Trap.

We report on the first detailed study of motional heating in a cryogenic Penning trap using a single antiproton. Employing the continuous Stern-Gerlach effect we observe cyclotron quantum transition rates of 6(1) quanta/h and an electric-field noise spectral density below 7.5(3.4)×10^{-20} V^{2} m^{-2} Hz^{-1}, which corresponds to a scaled noise spectral density below 8.8(4.0)×10^{-12} V^{2} m^{-2}, results which are more than 2 orders of magnitude smaller than those reported by other ion-trap experiments.

A parts-per-billion measurement of the antiproton magnetic moment.

Precise comparisons of the fundamental properties of matter-antimatter conjugates provide sensitive tests of charge-parity-time (CPT) invariance, which is an important symmetry that rests on basic assumptions of the standard model of particle physics. Experiments on mesons, leptons and baryons have compared different properties of matter-antimatter conjugates with fractional uncertainties at the parts-per-billion level or better. One specific quantity, however, has so far only been known to a fractional uncertainty at the parts-per-million level: the magnetic moment of the antiproton, . The extraordinary difficulty in measuring with high precision is caused by its intrinsic smallness; for example, it is 660 times smaller than the magnetic moment of the positron. Here we report a high-precision measurement of in units of the nuclear magneton µN with a fractional precision of 1.5 parts per billion (68% confidence level). We use a two-particle spectroscopy method in an advanced cryogenic multi-Penning trap system. Our result = -2.7928473441(42)µN (where the number in parentheses represents the 68% confidence interval on the last digits of the value) improves the precision of the previous best measurement by a factor of approximately 350. The measured value is consistent with the proton magnetic moment, µp = 2.792847350(9)µN, and is in agreement with CPT invariance. Consequently, this measurement constrains the magnitude of certain CPT-violating effects to below 1.8 × 10-24 gigaelectronvolts, and a possible splitting of the proton-antiproton magnetic moments by CPT-odd dimension-five interactions to below 6 × 10-12 Bohr magnetons.

Associations between different aspects of alcohol habits in adolescence, early adulthood, and early middle age: a prospective longitudinal study of a representative cohort of men and women.

Previous research has indicated that the relation between adolescent and adult alcohol habits is not very strong. The objective of the present study was to illustrate associations between different aspects of alcohol habits from adolescence to early middle age in a normal, representative Swedish birth cohort of male (n = 122) and female (n = 90) participants. The sample was prospectively followed by means of self-reports on drinking habits at ages 18, 25, and 36. The results show that heavy drinking at age 18 and frequent intoxication at age 25 substantially increase the risk of heavy consumption at age 36 but that hazardous alcohol habits at either age 18 or 25 alone cannot be considered a substantial risk factor.

Alcohol habits in a suburban male cohort.

OBJECTIVE: Using data from a prospective birth-to-maturity project, the study presents normally occurring variations in alcohol involvement of alcohol-related problems among a representative cohort of Swedish males in young middle age, born in a Swedish metropolitan area (n = 106). METHODS: Description and classification were based on an analysis of self-reported information (collected at about 36 years of age) about frequency and quantity of alcohol consumption (four-week timeline), self-reported alcohol-related symptoms, and registry data. RESULTS: According to a broad, operationally defined classification of "harmful drinking" (at least three alcohol-related symptoms, including alcohol-related crimes), 43 subjects (41%) had experienced a substantial drinking problem during their lifetime, to an extent that might warrant labels such as "alcoholism" or "hazardous drinking". About one-third of these misusers were currently using other drugs. Of the 106 subjects, 80 (75%) reported having had at least one alcohol-related symptom or problem at some time during their life. Taking various life events into account, including sociomedical circumstances and heavy consumption at 18 and 25 years, 23 subjects (22%) were classified as having a lifetime prevalence of alcohol abuse/dependence according to DSM-III criteria. CONCLUSION: Problem drinking was largely unknown to the healthcare system and only a few subjects had received treatment. The results are discussed in the light of data from other national and international epidemiological surveys.

Variations and stability in drinking patterns in a cohort of Swedish males.

OBJECTIVE: Information on drinking patterns may make an important contribution to our understanding of the risks and consequences of alcohol consumption. The objective of the present study is to describe variations and stability of patterns of alcohol use at both the aggregate and the individual levels. METHODS: The reported alcohol consumption was recorded of a normal, representative birth cohort of Swedish male (n = 122) subjects followed from the age of 18 years to early middle age and more extensively scrutinized at the age of 36, using a 28 day time-line follow-back technique. RESULTS: In young middle age a high proportion of total consumption occurred on Fridays and Saturdays (about 60%). In addition, it was possible to classify "standard drinkers", "sporadic binge drinkers", and "frequent drinkers" as separate clusters. CONCLUSION: While binge drinking was more stable than frequency of drinking from the age of 18 to the age of 36, frequent drinking showed the highest short-term stability at the age of 36 years.

Replication of the Stockholm Adoption Study of alcoholism. Confirmatory cross-fostering analysis.

BACKGROUND: Two forms of alcoholism with distinct clinical features and mode of inheritance were first distinguished in the Stockholm Adoption Study. This involved a large sample of children born in Stockholm, Sweden, who were adopted at an early age and reared by nonrelatives. Type 1 alcoholism had adult onset and rapid progression of dependence without criminality, whereas type 2 had teenage onset of recurrent social and legal problems from alcohol abuse. METHODS: A replication study was carried out with 577 men and 660 women born in Gothenburg, Sweden, and adopted at an early age/by nonrelatives. The genetic and environmental backgrounds of the adoptees were classified by the exact procedures calibrated by discriminant analysis in the original study. RESULTS: Both type 2 and severe type 1 alcoholism were confirmed as independently heritable forms of alcoholism in male adoptees. The lifetime risk of severe alcoholism was increased 4-fold in adopted men with both genetic and environmental risk factors characteristic of type 1 alcoholism compared with the others (11.4% vs 3.0%). Neither genetic nor environmental risk factors for type 1 alcoholism by themselves were sufficient to cause alcoholism. In contrast, the risk of type 2 alcoholism was increased 6-fold in adopted sons with a type 2 genetic background compared with others; regardless of their postnatal environment (10.7% vs 2.0%). The sons with a type 2 genetic background in the replication sample had no excess of type 1 alcoholism, and vice versa. There was no increased risk of mild abuse in adopted men regardless of their genetic or environmental background. CONCLUSION: Type 1 and type 2 alcoholism are clinically distinct forms of alcoholism with causes that are independent but not mutually exclusive.

Predisposition to criminality: Swedish adoption studies in retrospect.

The predisposition to criminality was studied in 913 women and 862 men from the Stockholm Adoption Study. Different genetic and environmental antecedents influenced the development of criminality, depending on whether or not there was associated alcohol abuse. Male alcoholic criminals often committed repeated violent offences, whereas non-alcoholic criminals characteristically committed a small number of petty property crimes. These non-alcoholic petty criminals more often had biological fathers with histories of petty crime but no excess of alcohol abuse. The risk of criminality in alcohol abusers was correlated with the severity of their own alcohol abuse, but not with criminality in their biological or adoptive parents. Most explained variation in petty crime was due to differences between the genetic predispositions of the adoptees, but substantial contributions were also made by postnatal environment, either alone or in combination with specific genetic subtypes. There was no overlap between the congenital antecedents of alcoholism and non-alcoholic criminality, but some postnatal variables were common to this kind of criminality and type 2 or male-limited alcoholism. Low social status alone was not sufficient to lead to petty criminality, but did increase risk in combination with specific types of genetic predisposition. Unstable preadoptive placement contributed to the risks of both petty criminality and male-limited alcoholism.

Managing patient equipment as an asset.

As materiel managers review asset management of patient equipment, it is important to remember that tracking the use, not the inventory of the equipment, could increase revenue and operating profits. Tracking utilization, making effective acquisition decisions with regard to purchasing, leasing or renting, and considering the life cycle and support necessary for products will optimize the management of capital assets, and produce real savings.

A twin study of autism in Denmark, Finland, Iceland, Norway and Sweden.

The Nordic countries were screened for the occurrence of cases of autism with a same-sexed twin under age 25 years. Twenty-one pairs (11 monozygotic and 10 dizygotic) of twins and one set of identical triplets were found and extensively examined. The concordance for autism by pair was 91% in the monoygotic and 0% in the dizygotic pairs. The corresponding concordances for cognitive disorder were 91% and 30%, respectively. In most of the pairs discordant for autism, the autistic twin had more perinatal stress. The results lend support for the notion that autism sometimes has a hereditary component and that perinatal stress is involved in some cases.

Childhood personality predicts alcohol abuse in young adults.

431 children (233 boys, 198 girls) born in Stockholm, Sweden, had a detailed behavioral assessment at 11 years of age, including a detailed interview with their school teachers, and at age 27 years were reevaluated to identify alcoholism or alcohol abuse. Specific predictions from a neurobiological learning theory about the role of heritable personality traits in susceptibility to alcohol abuse were tested in this prospective longitudinal study. Three dimensions of childhood personality variation were identified and rated without knowledge of adult outcome. These three dimensions (novelty-seeking, harm avoidance, and reward dependence) were largely uncorrelated with one another, and each was predictive of later alcohol abuse. Absolute deviations from the mean of each of the three personality dimensions were associated with an exponential increase in the risk of later alcohol abuse. High novelty-seeking and low harm avoidance were most strongly predictive of early-onset alcohol abuse. These two childhood variables alone distinguished boys who had nearly 20-fold differences in their risk of alcohol abuse: the risk of alcohol abuse varied from 4 to 75% depending on childhood personality.

Genetic heterogeneity and the classification of alcoholism.

Recent progress toward a systematic pathophysiological model of alcoholism has led to identification of two distinct subtypes of alcoholism. These subtypes may be distinguished in terms of distinct alcohol-related symptoms, personality traits, ages of onset, and patterns of inheritance. Type 1 alcoholism is characterized by anxious (passive-dependent) personality traits and rapid development of tolerance and dependence on the anti-anxiety effects of alcohol. This leads to loss of control, difficulty terminating binges once they start, guilt feelings, and liver complications following socially encouraged exposure to alcohol intake. In contrast, type 2 alcoholism is characterized by antisocial personality traits and persistent seeking of alcohol for its euphoriant effects. This leads to early onset of inability to abstain entirely, as well as fighting and arrests when drinking. Empirical findings about sex differences, ages of onset, associated personality traits, and longitudinal course are described in a series of adoption and family studies in Sweden and the United States. Implications for future research and clinical practice are discussed.

Structure and stability of childhood personality: prediction of later social adjustment.

Four hundred and thirty-one children (233 boys, 198 girls) born in Stockholm, Sweden had detailed behavioral assessments at 11 and 15 yrs of age, including a detailed interview with their school teachers and at age 27 yrs were re-evaluated to identify convictions for violent or property crimes. Three dimensions of childhood personality variation were identified and rated without knowledge of later outcome. These three dimensions (novelty-seeking, harm-avoidance and reward-dependence) were largely uncorrelated with one another and each was moderately predictive of later personal and social adjustment, including type of adult criminality. Factor and correlational analyses confirmed predictions that the number and structure of personality dimensions based on teacher ratings throughout childhood is similar to that observed in self-reports by adults.

Alcoholism: lessons from population, family and adoption studies.

Recent population, family and adoption studies suggest that the susceptibility to alcoholism is a heterogenous phenomenon. Specific combinations of predisposing genetic factors and environmental stressors appear to interact before alcoholism develops. These studies indicate that the increasing use of alcohol markedly influence the observed inheritance of alcohol abuse. It is concluded that the problems of alcoholism is less a medical than a political problem.