Polarization of electric field noise near metallic surfaces

Electric field noise in proximity to metallic surfaces is a poorly understood phenomenon that appears in different areas of physics. Trapped ion quantum information processors are particular susceptible to this noise, leading to motional decoherence which ultimately limits the fidelity of quantum operations. On the other hand they present an ideal tool to study this effect, opening new possibilities in surface science. In this work we analyze and measure the polarization of the noise field in a micro-fabricated ion trap for various noise sources. We find that technical noise sources and noise emanating directly from the surface give rise to different degrees of polarization which allows us to differentiate between the two noise sources. Based on this, we demonstrate a method to infer the magnitude of surface noise in the presence of technical noise

Two mode coupling in a single ion oscillator via parametric resonance

Atomic ions, confined in radio-frequency Paul ion traps, are a promising candidate to host a future quantum information processor. In this letter, we demonstrate a method to couple two motional modes of a single trapped ion, where the coupling mechanism is based on applying electric fields rather than coupling the ion's motion to a light field. This reduces the design constraints on the experimental apparatus considerably. As an application of this mechanism, we cool a motional mode close to its ground state without accessing it optically. As a next step, we apply this technique to measure the mode's heating rate, a crucial parameter determining the trap quality. In principle, this method can be used to realize a two-mode quantum parametric amplifier.Comment: 8 pages, 5 figure

Relaxation dynamics of the toric code in contact with a thermal reservoir: Finite-size scaling in a low temperature regime

We present an analysis of the relaxation dynamics of finite-size topological qubits in contact with a thermal bath. Using a continuous-time Monte Carlo method, we explicitly compute the low-temperature nonequilibrium dynamics of the toric code on finite lattices. In contrast to the size-independent bound predicted for the toric code in the thermodynamic limit, we identify a low-temperature regime on finite lattices below a size-dependent crossover temperature with nontrivial finite-size and temperature scaling of the relaxation time. We demonstrate how this nontrivial finite-size scaling is governed by the scaling of topologically nontrivial two-dimensional classical random walks. The transition out of this low-temperature regime defines a dynamical finite-size crossover temperature that scales inversely with the log of the system size, in agreement with a crossover temperature defined from equilibrium properties. We find that both the finite-size and finite-temperature scaling are stronger in the low-temperature regime than above the crossover temperature. Since this finite-temperature scaling competes with the scaling of the robustness to unitary perturbations, this analysis may elucidate the scaling of memory lifetimes of possible physical realizations of topological qubits.Comment: 14 Pages, 13 figure

Engineering vibrationally-assisted energy transfer in a trapped-ion quantum simulator

Many important chemical and biochemical processes in the condensed phase are notoriously difficult to simulate numerically. Often this difficulty arises from the complexity of simulating dynamics resulting from coupling to structured, mesoscopic baths, for which no separation of time scales exists and statistical treatments fail. A prime example of such a process is vibrationally assisted charge or energy transfer. A quantum simulator, capable of implementing a realistic model of the system of interest, could provide insight into these processes in regimes where numerical treatments fail. We take a first step towards modeling such transfer processes using an ion trap quantum simulator. By implementing a minimal model, we observe vibrationally assisted energy transport between the electronic states of a donor and an acceptor ion augmented by coupling the donor ion to its vibration. We tune our simulator into several parameter regimes and, in particular, investigate the transfer dynamics in the nonperturbative regime often found in biochemical situations

Prenatal Predictors of Infant Self-Regulation: The Contributions of Placental DNA Methylation of NR3C1 and Neuroendocrine Activity

We examined whether placental DNA methylation of the glucocorticoid receptor gene, NR3C1 was associated with self-regulation and neuroendocrine responses to a social stressor in infancy. Placenta samples were obtained at birth and mothers and their infants (n = 128) participated in the still-face paradigm when infants were 5 months old. Infant self-regulation following the still-face episode was coded and pre-stress cortisol and cortisol reactivity was assessed in response to the still-face paradigm. A factor analysis of NR3C1 CpG sites revealed two factors: one for CpG sites 1-4 and the other for sites 5-13. DNA methylation of the factor comprising NR3C1 CpG sites 5-13 was related to greater cortisol reactivity and infant self-regulation, but cortisol reactivity was not associated with infant self-regulation. The results reveal that prenatal epigenetic processes may explain part of the development of infant self-regulation

Comprehensive genetic assessment of the ESR1 locus identifies a risk region for endometrial cancer

Excessive exposure to estrogen is a well-established risk factor for endometrial cancer (EC), particularly for cancers of endometrioid histology. The physiological function of estrogen is primarily mediated by estrogen receptor alpha, encoded by ESR1. Consequently, several studies have investigated whether variation at the ESR1 locus is associated with risk of EC, with conflicting results. We performed comprehensive fine-mapping analyses of 3633 genotyped and imputed single nucleotide polymorphisms (SNPs) in 6607 EC cases and 37 925 controls. There was evidence of an EC risk signal located at a potential alternative promoter of the ESR1 gene (lead SNP rs79575945, P=1.86x10(-5)), which was stronger for cancers of endometrioid subtype (P=3.76x10(-6)). Bioinformatic analysis suggests that this risk signal is in a functionally important region targeting ESR1, and eQTL analysis found that rs79575945 was associated with expression of SYNE1, a neighbouring gene. In summary, we have identified a single EC risk signal located at ESR1, at study-wide significance. Given SNPs located at this locus have been associated with risk for breast cancer, also a hormonally driven cancer, this study adds weight to the rationale for performing informed candidate fine-scale genetic studies across cancer types

Comprehensive genetic assessment of the ESR1 locus identifies a risk region for endometrial cancer.

Excessive exposure to estrogen is a well-established risk factor for endometrial cancer (EC), particularly for cancers of endometrioid histology. The physiological function of estrogen is primarily mediated by estrogen receptor alpha, encoded by ESR1. Consequently, several studies have investigated whether variation at the ESR1 locus is associated with risk of EC, with conflicting results. We performed comprehensive fine-mapping analyses of 3633 genotyped and imputed single nucleotide polymorphisms (SNPs) in 6607 EC cases and 37 925 controls. There was evidence of an EC risk signal located at a potential alternative promoter of the ESR1 gene (lead SNP rs79575945, P=1.86×10(-5)), which was stronger for cancers of endometrioid subtype (P=3.76×10(-6)). Bioinformatic analysis suggests that this risk signal is in a functionally important region targeting ESR1, and eQTL analysis found that rs79575945 was associated with expression of SYNE1, a neighbouring gene. In summary, we have identified a single EC risk signal located at ESR1, at study-wide significance. Given SNPs located at this locus have been associated with risk for breast cancer, also a hormonally driven cancer, this study adds weight to the rationale for performing informed candidate fine-scale genetic studies across cancer types.This work was supported by the National Health and Medical Research Council of Australia (ID#1031333 to A B Spurdle, DF, A M Dunning, ID#39435 to ANECS, ID#552402, QIMR Controls); National Health and Medical Research Council of Australia Fellowship Scheme (to A B Spurdle); Principal Research Fellow of Cancer Research UK (to D F Easton); Joseph Mitchell Trust (to A M Dunning); Oxford Comprehensive Biomedical Research Centre (to I Tomlinson); The European Community's Seventh Framework Programme (grant agreement number 22175 (HEALTH-F2-2009-223175) (COGS); Cancer Research UK (C1287/A10118 to COGS and BCAC, C1287/A10710, C12292/A11174, C1281/A12014 to COGS and BCAC, C5047/A15007, C5047/A10692, C8197/A16565, C490/A10124 to SEARCH, CORGI - NSECG, to I Tomlinson); National Institutes of Health (CA128978, R01 CA122443 to MECS and MAY, P30 CA15083 to MECS, P50 CA136393 to MECS and MAY, CAHRES); Post-Cancer GWAS Initiative (1U19 CA148537, 1U19 CA148065, 1U19 CA148112 – the GAME-ON initiative); Department of Defence (W81XWH-10-1-0341); Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer; Komen Foundation for the Cure; The Breast Cancer Research Foundation; Ovarian Cancer Research Fund (to COGS); Cancer Council Queensland (ID#4196615 to ANECS); Council Cancer Tasmania (ID#403031, #ID457636 to ANECS); Medical Research Council (G0000934 to the British 1958 Birth Cohort); Wellcome Trust (068545/Z/02, 085475 to the British 1958 Birth Cohort); Wellcome Trust Human Genetics Grant (090532/Z/09/Z to NSECG); European Union (EU FP7 CHIBCHA to NSECG); The University of Newcastle (to QIMR Controls, to NECS); Gladys M Brawn Senior Research Fellowship (QIMR Controls); The Vincent Fairfax Family Foundation (QIMR Controls); Hunter Medical Research Institute (HCS, NECS); Hunter Area Pathology Service (HCS); ELAN fund of the University of Erlangen (BECS); Verelst Foundation for endometrial cancer (LES); Fred C and Katherine B Anderson Foundation (to MECS, to MAY); Mayo Foundation (to MECS, to MAY); Ovarian Cancer Research Fund with support of the Smith family, in memory of Kathryn Sladek Smith (MECS, PPD/RPCI.07 to OCAC); Helse Vest Grant (MoMaTEC); University of Bergen (MoMaTEC); Melzer Foundation (MoMaTEC); The Norwegian Cancer Society – Harald Andersens legat (MoMaTEC); The Research Council of Norway (MoMaTEC); Haukeland University of Hospital (MoMaTEC); NBN Children's Cancer Research Group (NECS); Ms Jennie Thomas (NECS); regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet (20110222, 20110483, 20110141 and DF 07015 all to RENDOCAS, to KARBAC); The Swedish Labor Market Insurance (100069 to RENDOCAS); The Swedish Cancer Society (11 0439 to RENDOCAS); Agency for Science, Technology and Research of Singapore (CAHRES); Susan G Komen Breast Cancer Foundation (CAHRES); UK National Institute for Health Research Biomedical Research Centres at the University of Cambridge (OCAC); Baden-Württemberg state Ministry of Science, Research and Arts (ESTHER); Federal Ministry of Family Affairs, Senior Citizens, Women and Youth (ESTHER); Federal Ministry of Education and Research (BMBF) Germany (01KW9975/5 to GENICA, 01KW9976/8 to GENICA, 01KW9977/0 to GENICA, 01KW0114 to GENICA, to ESTHER); Robert Bosch Foundation (GENICA); Deutsches Krebsforschungszentrum – DKFZ (GENICA); Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University Bochum, IPA (GENICA); Department of Internal Medicine, Evangelische Kliniken Bonn gGmbH, Johanniter Krankenhaus (GENICA); Deutsche Krebshilfe e.V. (70-2892-BR I to MARIE); Hamburg Cancer Society (MARIE); German Cancer Research Center (MARIE); Breast Cancer Research Foundation (MCBCS); David F. and Margaret T. Grohne Family Foundation (MCBCS); Ting Tsung and Wei Fong Chao Foundation (MCBCS); VicHealth (MCCS); Cancer Council Victoria (MCCS); Breakthrough Breast Cancer (UKBGS); Institute of Cancer Research (UKBGS); and NHS funding to the NIHR Biomedical Research Centre (UKBGS/ICR).This is the final version of the article. It first appeared from the Society for Endocrinology via http://dx.doi.org/10.1530/ERC-15-031

CYP19A1 fine-mapping and Mendelian randomization: estradiol is causal for endometrial cancer.

Candidate gene studies have reported CYP19A1 variants to be associated with endometrial cancer and with estradiol (E2) concentrations. We analyzed 2937 single nucleotide polymorphisms (SNPs) in 6608 endometrial cancer cases and 37 925 controls and report the first genome wide-significant association between endometrial cancer and a CYP19A1 SNP (rs727479 in intron 2, P=4.8×10(-11)). SNP rs727479 was also among those most strongly associated with circulating E2 concentrations in 2767 post-menopausal controls (P=7.4×10(-8)). The observed endometrial cancer odds ratio per rs727479 A-allele (1.15, CI=1.11-1.21) is compatible with that predicted by the observed effect on E2 concentrations (1.09, CI=1.03-1.21), consistent with the hypothesis that endometrial cancer risk is driven by E2. From 28 candidate-causal SNPs, 12 co-located with three putative gene-regulatory elements and their risk alleles associated with higher CYP19A1 expression in bioinformatical analyses. For both phenotypes, the associations with rs727479 were stronger among women with a higher BMI (Pinteraction=0.034 and 0.066 respectively), suggesting a biologically plausible gene-environment interaction.Fine-mapping analysis was supported by NHMRC project grant [ID#1031333] to ABS, DFE and AMD. ABS, PW, GWM, and DRN are supported by the NHMRC Fellowship scheme. AMD is supported by the Joseph Mitchell Trust. IT is supported by Cancer Research UK and the Oxford Comprehensive Biomedical Research Centre. Funding for the iCOGS infrastructure came from: the European Community's Seventh Framework Programme under grant agreement no 223175 [HEALTH-F2-2009-223175] [COGS], Cancer Research UK [C1287/A10118, C1287/A 10710, C12292/A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692, C8197/A16565], the National Institutes of Health [CA128978] and Post-Cancer GWAS initiative [1U19 CA148537, 1U19 CA148065 and 1U19 CA148112 - the GAME-ON initiative], the Department of Defence [W81XWH-10-1-0341], the Canadian Institutes of Health Research [CIHR] for the CIHR Team in Familial Risks of Breast Cancer, Komen Foundation for the Cure, the Breast Cancer Research Foundation, and the Ovarian Cancer Research Fund. ANECS recruitment was supported by project grants from the NHMRC [ID#339435], The Cancer Council Queensland [ID#4196615] and Cancer Council Tasmania [ID#403031 and ID#457636]. SEARCH recruitment was funded by a programme grant from Cancer Research UK [C490/A10124]. Stage 1 and stage 2 case genotyping was supported by the NHMRC [ID#552402, ID#1031333]. This study 647 makes use of data generated by the Wellcome Trust Case-Control Consortium (WTCCC). A full list of the investigators who contributed to the generation of the data is available from www.wtccc.org.uk. Funding for the project was provided by the Wellcome Trust under award 076113. We acknowledge use of DNA from the British 1958 Birth Cohort collection, funded by the Medical Research Council grant G0000934 and the Wellcome Trust grant 068545/Z/02 - funding for this project was provided by the Wellcome Trust under award 085475. NSECG was supported by the EU FP7 CHIBCHA grant and Wellcome Trust Centre for Human Genetics Grant 090532/Z/09Z, and CORGI by Cancer Research UK. Recruitment of the QIMR Berghofer controls was supported by the NHMRC. The University of Newcastle, the Gladys M Brawn Senior Research Fellowship scheme, The Vincent Fairfax Family Foundation, the Hunter Medical Research Institute and the Hunter Area Pathology Service all contributed towards the costs of establishing the Hunter Community Study. The Bavarian Endometrial Cancer Study (BECS) was partly funded by the ELAN fund of the University of Erlangen. The Leuven Endometrium Study (LES) was supported by the Verelst Foundation for endometrial cancer. The Mayo Endometrial Cancer Study (MECS) and Mayo controls (MAY) were supported by grants from the National Cancer Institute of United States Public Health Service [R01 CA122443, P30 CA15083, P50 CA136393, and GAME-ON the NCI Cancer Post-GWAS Initiative U19 CA148112], the Fred C and Katherine B Andersen Foundation, the Mayo Foundation, and the Ovarian Cancer Research Fund with support of the Smith family, in memory of Kathryn Sladek Smith. MoMaTEC received financial support from a Helse Vest Grant, the University of Bergen, Melzer Foundation, The Norwegian Cancer Society (Harald Andersens legat), The Research Council of Norway and Haukeland University Hospital. 672 The Newcastle Endometrial Cancer Study (NECS) acknowledges contributions from the University of Newcastle, The NBN Children’s Cancer Research Group, Ms Jennie Thomas and the Hunter Medical Research Institute. RENDOCAS was supported through the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet [numbers: 20110222, 20110483, 20110141 and DF 07015], The Swedish Labor Market Insurance [number 100069] and The Swedish Cancer Society [number 11 0439]. The Cancer Hormone Replacement Epidemiology in Sweden Study (CAHRES, formerly called The Singapore and Swedish Breast/Endometrial Cancer Study; SASBAC) was supported by funding from the Agency for Science, Technology and Research of Singapore (A*STAR), the US National Institutes of Health and the Susan G. Komen Breast Cancer Foundation. The Breast Cancer Association Consortium (BCAC) is funded by Cancer Research UK [C1287/A10118, C1287/A12014]. The Ovarian Cancer Association Consortium (OCAC) is supported by a grant from the Ovarian Cancer Research Fund thanks to donations by the family and friends of Kathryn Sladek Smith [PPD/RPCI.07], and the UK National Institute for Health Research Biomedical Research Centres at the University of Cambridge. Additional funding for individual control groups is detailed in the Supplementary Information. EPIC-Norfolk was funded by research programme grant funding from Cancer Research UK and the Medical Research Council with additional support from the Stroke Association, British Heart Foundation, Department of Health, Research into Ageing and Academy of Medical Sciences. The SIBS study was supported by program grant C1287/A10118 and project grants from Cancer Research 697 UK (grant numbers C1287/8459).This is the author accepted manuscript. The final version is available from Bioscientifica via http://dx.doi.org/10.1530/ERC-15-038