Interaction versus dimerization in one-dimensional Fermi systems

In order to study the effect of interaction and lattice distortion on quantum coherence in one-dimensional Fermi systems, we calculate the ground state energy and the phase sensitivity of a ring of interacting spinless fermions on a dimerized lattice. Our numerical DMRG (Density Matrix Renormalization Group) studies, in which we keep up to 1000 states for systems of about 100 sites, are supplemented by analytical considerations using bosonization techniques. We find a delocalized phase for an attractive interaction, which differs from that obtained for random lattice distortions. The extension of this delocalized phase depends strongly on the dimerization induced modification of the interaction. Taking into account the harmonic lattice energy, we find a dimerized ground state for a repulsive interaction only. The dimerization is suppressed at half filling, when the correlation gap becomes large.Comment: EPJ-style, 8 pages including 12 figures, to be published in EPJ

Charge redistribution at YBa2Cu3O7-metal interfaces

Charge redistribution at interfaces is crucial for electronic applications of high-Tc superconductors, since the band structure is modified on a local scale. We address the normal-state electronic structure of YBa2Cu3O7 (YBCO) at an YBCO-metal contact by first principles calculations for prototypical interface configurations. We derive quantitative results for the intrinsic doping of the superconducting CuO2 planes due to the metal contact. Our findings can be explained in terms of a band-bending mechanism, complemented by local screening effects. We determine a net charge transfer of 0.09 to 0.13 electrons in favour of the intraplane Cu sites, depending on the interface orientation.Comment: 3 pages, 2 figures, submitted to Appl. Phys. Let

On the ferromagnetic character of (LaVO3_3)m_m/SrVO3_3 superlattices

The experimental observation that vanadate superlattices (LaVO$_3$)$_m$/SrVO$_3$ show ferromagnetism up to room temperature [U.\ L\"uders {\it et al.}, Phys.\ Rev.\ B {\bf 80}, 241102R (2009)] is investigated by means of density functional theory. First, the influence of the density functional on the electronic and magnetic structure of bulk ${\rm LaVO_3}$ is discussed. Second, the band structure of a (LaVO$_3$)$_m$/SrVO$_3$ slab for $m=5$ and 6 is calculated. Very different behaviors for odd and even values of $m$ are found: In the odd case lattice relaxation results into a buckling of the interface VO$_2$ layers that leads to spin-polarized interfaces. In the even case a decoupling of the interface VO$_2$ layers from the LaO layers is obtained, confining the interface electrons into a two-dimensional electron gas. The orbital reconstruction at the interface due to the lattice relaxation is discussed.Comment: 8 pages, 7 figure

EVALUATING THE EFFECTS OF ELECTRONIC NICOTINE DELIVERY SYSTEMS ON SMOKING REDUCTION, NEGATIVE MOOD, AND STRESS AMONG SMOKERS WITH MENTAL ILLNESS

Introduction: Smokers with mental illness (MI) are disproportionately affected by negative health outcomes. Electronic nicotine delivery systems (ENDS) may represent a harm reduction tool for those who reduce and/or replace their cigarettes with ENDS. Little previous research has examined how smokers with MI respond to ENDS. This analysis aimed to address this research gap using secondary data from a randomized controlled trial of ENDS varying in nicotine delivery among smokers with and without current MI. The aims were to test 1) the effects of MI status, condition, and time on changes in smoking behavior and negative mood and stress measures, 2) whether changes in negative mood and stress mediate condition-related effects on smoking, and 3) whether this mediation was moderated by MI status. Methods: Smokers (n=520) interested in reduction but not cessation were randomized to receive either a non-nicotine-containing plastic cigarette substitute (CIG SUB) or ENDS differing in liquid nicotine concentration (0, 8, or 36 mg/ml) for 24 weeks. MI status was assessed at baseline. Smoking behavior (cigarettes per day; CPD) and negative mood (depression, psychological distress) and perceived stress measures were assessed at week 0, 4, 8, 16, and 24. Conditions were collapsed by nicotine-containing status (CIG SUB/0 mg/ml vs. 8/36 mg/ml), and participants were categorized by MI status (yes, no). Linear mixed models and mediation models were used. Sensitivity analyses included covariate adjustment. Results: CPD reduction was significantly greater among smokers without MI at week 16 and 24 for the unadjusted analysis only. Nicotine conditions were associated with significantly greater CPD reduction at all time points, and both condition groupings resulted in significant CPD reduction relative to baseline. Significantly greater depressive symptoms were observed for non-nicotine conditions at week 4; significantly greater psychological distress was observed for non-nicotine conditions at week 24. With covariate adjustment, negative mood measures were significantly higher at later study time points for those with MI. Perceived stress differed by MI status but not condition grouping. Changes in negative mood and stress did not mediate CPD reduction, but direct effects of condition as well as changes in negative mood on CPD reduction were observed. Conclusions: Our findings indicate that smokers with MI may experience greater difficulty reducing CPD, but nicotine conditions had similar effectiveness in reducing CPD relative to non-nicotine conditions among smokers with and without MI. Smokers with MI reported increased negative mood at some time points, but changes in negative mood and stress did not explain the relationship between condition and CPD reduction. Results highlight the need for mood management during smoking reduction and cessation efforts for smokers with MI and support the idea that ENDS may be an effective tool for smoking reduction for this group

Dog Barking at the Moon: Transcreation of a Meme in Art and Poetry

This essay explores the dynamics of transcreation in art and poetry, focusing on the image of a dog barking at the moon in four Taiwanese poems. By putting them in connection with each other and with other texts from different times and artistic traditions, I wish to contribute to a dismantling of the “influence paradigm,” move beyond contestations over the comparative approach, and demonstrate a critical method that recognizes the enduring fascination for the meme but equally appreciates change, approximation and adaptation, rather than closed-off conversion from a source text to a target text

Thinking Other People's Thoughts: Brian Holton's Translations from Classical Chinese into Scots

Brian Holton (b. 1949), the only currently working translator of classical Chinese poetry into Scots, is here approached biographically, through his personal history and his career in translating and publishing. Holton's collection of his own translation materials, including drafts, proofs, scores, translations, notes, lectures, correspondence, and journalistic writings, has been made available to the author. As a voice of history, Holton's life and work constitute a subjective narrative that enters into debate, discussion, and interpretation with larger narratives, spheres of diffusion, and power relations. Hence the discussion touches on such matters as as language policy in education and national literatures, and issues of centre and periphery, foreignization and domestication

Breaking Language Down: Taiwan Sound Poetry and its Ways of Saying

This paper explores the appearance and rapid development of a genre that crosses the boundaries between art, music, drama, and literature, and that is being variously called ＂sound poetry＂ (聲音詩 shengyin shi), ＂language art＂ (語言藝術 yuyan yishu), or ＂text-sound art＂ (文本聲音藝術 wenben shengyin yishu). I argue that Taiwan sound poetry develops as an alternative genre to Chinese poetic tradition, forging a disorienting aesthetics that is disruptive of conventional ideas of artistic quality. I conceptualize this phenomenon in its unique history and politics, extrapolating some key features that include: a poetics that strives not for semantic extension or enrichment, but that radically aims at ＂semantic abjection＂; intervention in Taiwan language politics and translingual context, through its contribution to a ＂culture of the ear＂; a shift of attention from textual semantics to performance with audience/users' participation; strategic denial of a genealogy rooted in the Chinese tradition, with sound poets' pronouncements about their poetics as being an entirely Western import; double nature as local, Sinophone, and global