2,001 research outputs found

    Symmetric and antisymmetric exchange anisotropies in quasi-one-dimensional CuSe2_2O5_5 as revealed by ESR

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    We present an electron spin resonance (ESR) study of single-crystalline spin chain-system CuSe2_2O5_5 in the frequency range between 9 GHz and 450 GHz. In a wide temperature range above the N\'{e}el temperature TN=17T_N=17 K we observe strong and anisotropic frequency dependence of a resonance linewidth. Although sizeable interchain interaction JIC≈0.1JJ_{IC}\approx 0.1 J (JJ is the intrachain interaction) is present in this system, the ESR results agree well with the Oshikawa-Affleck theory for one-dimensional S=1/2S=1/2 Heisenberg antiferromagnet. This theory is used to extract the anisotropies present in CuSe2_2O5_5. We find that the symmetric anisotropic exchange Jc=(0.04±0.01) JJ_c=(0.04 \pm 0.01) \:J and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction D=(0.05±0.01) JD=(0.05\pm 0.01)\:J are very similar in size in this system. Staggered-field susceptibility induced by the presence of the DM interaction is witnessed in the macroscopic susceptibility anisotropy.Comment: 8 pages, 7 figures, 2 tables, published in Phys. Rev.

    Fifteen years of NESDA Neuroimaging:An overview of results related to clinical profile and bio-social risk factors of major depressive disorder and common anxiety disorders

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    The longitudinal Netherlands Study of Depression and Anxiety (NESDA) Neuroimaging study was set up in 2003 to investigate whether neuroanatomical and functional abnormalities during tasks of primary emotional processing, executive planning and memory formation, and intrinsic brain connectivity are i) shared by individuals with major depressive disorder (MDD) and common anxiety disorders; and ii) characterized by symptomatologyspecific abnormalities. Furthermore, questions related to individual variations in vulnerability for onset, comorbidity, and longitudinal course could be investigated.& nbsp; Between 2005 and 2007, 233 individuals fulfilling a diagnosis of MDD, panic disorder, social anxiety disorder and/or generalized anxiety disorder and 68 healthy controls aging between 18 and 57 were invited from the NESDA main sample (n = 2981). An emotional faces processing task, an emotional word-encoding task, and an executive planning task were administered during 3T BOLD-fMRI acquisitions. In addition, resting state BOLDfMRI was acquired and T1-weighted structural imaging was performed. All participants were invited to participate in the two-year and nine-year follow-up MRI measurement.& nbsp; Fifteen years of NESDA Neuroimaging demonstrated common morphological and neurocognitive abnormalities across individuals with depression and anxiety disorders. It however provided limited support for the idea of more extensive abnormalities in patients suffering from both depression and anxiety, despite their worse prognosis. Risk factors including childhood maltreatment and specific risk genes had an emotion processing modulating effect, apparently stronger than effects of diagnostic labels. Furthermore, brain imaging data, especially during emotion processing seemed valuable for predicting the long-term course of affective disorders, outperforming prediction based on clinical information alone

    Coherent manipulation of electron spins up to ambient temperatures in Cr5+^{5+}(S=1/2) doped K3_3NbO8_8

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    We report coherent spin manipulation on Cr5+^{5+} (\emph{S} = 1/2, \emph{I} = 0) doped K3_3NbO8_8, which constitutes a dilute two-level model relevant for use as a spin qubit. Rabi oscillations are observed for the first time in a spin system based on transition metal oxides up to room temperature. At liquid helium temperature the phase coherence relaxation time \emph{T2T_2} reaches ∼10\sim 10 μ\mus and, with a Rabi frequency of 20 MHz, yields a single qubit figure of merit \emph{QMQ_M} of about 500. This shows that a diluted ensemble of Cr5+^{5+} (\emph{S} = 1/2) doped K3_3NbO8_8 is a potential candidate for solid-state quantum information processing.Comment: 4 page

    Rotationally induced Penning ionization of ultracold photoassociated helium dimers

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    We have studied photoassociation of metastable \tripS helium atoms near the \tripS-\tripP asymptote by both ion detection in a magneto-optical trap and trap-loss measurements in a magnetic trap. A detailed comparison between the results of the two experiments gives insight into the mechanism of the Penning ionization process. We have identified four series of resonances corresponding to vibrational molecular levels belonging to different rotational states in two potentials. The corresponding spin states become quasi-purely quintet at small interatomic distance, and Penning ionization is inhibited by spin conservation rules. Only a weak rotational coupling is responsible for the contamination by singlet spin states leading to a detectable ion signal. However, for one of these series Bose statistics does not enable the rotational coupling and the series detected through trap-loss does not give rise to sufficient ionization for detection.Comment: 7 pages, 4 figures, submitted to EuroPhysics Letter

    Consolation through music: A survey study

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    Even though music is widely used as a source of solace, the question as to how and why music offers consolation remains largely unexplored. The aims of the present study are as follows: (a) to compare listening to music versus other self-soothing behaviors, (b) to explore when music is used as a means for solace, (c) to identify aspects of music that are important for providing solace, and (d) to explore behavior while listening to consoling music. Participants completed an internet survey distributed through the websites of Dutch National Radio 2 and Radio 4 (N = 445). The survey consisted of the Geneva Emotion and Music Scale (GEMS), the solace-scale from the Music in Mood Regulation questionnaire (MMR), questions concerning means of solace, situations requiring comfort, song aspects, and feelings and activities during music listening. The main findings indicate that: (1) music is the most important source of consolation compared with other soothing behaviors, (2) situations in which people have experienced loss and sadness are the primary situations in which music offers solace, (3) consoling music induces a feeling of being moved and a mixture of both positive and sad emotions; the most important aspects of a song for soothing purposes are the music itself and the lyrics, and (4) music for comfort is listened to predominately in solitude, as the sole activity. On the basis of these findings, a characterization of listening to consoling music is compiled. Behavior and song aspects are discussed in terms of how and why they are helpful in providing solace
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