4,792 research outputs found
Vestiges of Topological Phase Transitions in Kitaev Quantum Spin Liquids
Get PDFWe investigate signatures of topological quantum phase transitions (TQPTs) between the Z2 quantum spin liquids (QSLs). In two spatial dimensions, Z2 QSLs and their TQPTs are only well defined at zero temperature (T 1⁄4 0), and it is imperative to clarify their observable signatures under nonzero temperatures. Here, we present the vestiges of TQPTs between Z2 QSLs with Majorana fermions in terms of thermal Hall conductivity κxy at nonzero temperatures. The κxy=T shows characteristic temperature dependences around TQPTs. We argue that an exponential upturn near T 1⁄4 0 and the peak of κxy=T around massive excitation energy are observable smoking-gun signals of the TQPTs. Quantum critical fan-shape temperature dependences are uncovered across TQPTs. We also perform the parton mean-field analysis on a modified Kitaev model with next-nearest neighbor interactions finding TQPTs between the phases with different Chern numbers and their vestiges self-consistently. We discuss the implication of our results to the recent experiments in α-RuCl3. © 2019 American Physical Societ
Identification of a Kitaev quantum spin liquid by magnetic field angle dependence
No full text© 2022, The Author(s).Quantum spin liquids realize massive entanglement and fractional quasiparticles from localized spins, proposed as an avenue for quantum science and technology. In particular, topological quantum computations are suggested in the non-abelian phase of Kitaev quantum spin liquid with Majorana fermions, and detection of Majorana fermions is one of the most outstanding problems in modern condensed matter physics. Here, we propose a concrete way to identify the non-abelian Kitaev quantum spin liquid by magnetic field angle dependence. Topologically protected critical lines exist on a plane of magnetic field angles, and their shapes are determined by microscopic spin interactions. A chirality operator plays a key role in demonstrating microscopic dependences of the critical lines. We also show that the chirality operator can be used to evaluate topological properties of the non-abelian Kitaev quantum spin liquid without relying on Majorana fermion descriptions. Experimental criteria for the non-abelian spin liquid state are provided for future experiments.11Nsciescopu
The stability of hole-doped antiferromagnetic state in a two-orbital model
Get PDFWe investigate the hole-doped antiferromagnetic state in a two-orbital model of cuprates. The
model also includes d3z2−r2 orbital. Unlike the one-orbital model, we find the antiferromagnetic
state stable against the hole doping for the cuprates with orbital splitting between dx2−y2 and d3z2−r2
orbitals being ∼1 eV. This results from the fact that the Hund’s coupling enforces the filling of
dx2−y2 orbital ≈1 indicated by a significant reduction of dx2−y2 spectral density at the Fermi level.
This, in turn, leads to the suppression of intraband fluctuations detrimental to the
antiferromagnetic phase. In this scenario, hole doping involves removal of mainly d3z2−r2 electrons
that are comparatively more localized. One important caveat of our meanfield theoretic result and
conclusion is that they are reliable only for a very low hole doping region.11Yscopu
Interplay between spin-orbit coupling and Van Hove singularity in the Hund's metallicity of Sr2RuO4
No full text© 2020 American Physical Society. We investigate the roles of spin-orbit coupling and the Van Hove singularity in the dynamical properties of Sr2RuO4, which become prominent at zero and very low temperature, by means of density functional theory plus dynamical mean-field theory with an exact diagonalization solver. We examine the crossover between a Fermi liquid and a Hund's metal for a wide range of temperatures and Hund's coupling. In the absence of doping, we confirm that the Fermi liquid persists at zero temperature even with nonzero Hund's coupling. The freezing-moment mechanism suggests that thermal fluctuations lead to a suppression of the Fermi liquid phase and promote Hund's metallicity with incoherence. We show that the Van Hove singularity is an additional key ingredient to drive the suppression at very low temperature by observing a doping dependence of the freezing or long-lived paramagnetic moments. The role of spin-orbit coupling is marked by an amplified Van Vleck contribution of spin susceptibility, significantly promoting Hund's metallicity. Together with the known doping dependence of Hund's metallicity, the additional Van Hove singularity doping dependence found here may allow for the control of the Hund's metallicity of Sr2RuO4(t2g4) by a fine tuning of the doping or possibly even strain11sciescopu
Hund's metallicity enhanced by a van Hove singularity in cubic perovskite systems
No full text© 2021 American Physical Society.A van Hove singularity (VHS) often significantly amplifies the electronic instability of a crystalline solid, including correlation-induced phenomena such as Hund's metallicity. We perform a systematic study on the interplay between Hund's coupling and electronic structures with a VHS focusing on Hund's metallicity. We construct a simplified tight-binding model targeting cubic perovskite materials and test the effects of the VHS utilizing dynamical mean-field theory with an exact diagonalization solver. The quasiparticle weight and the low-frequency power exponent of the self-energy provide a quantitative estimation of metallicity over the phase diagram. We find the VHS to substantially enhance Hund's metallicity. The results here suggest a range of parameters through which a VHS can bring great synergy with Hund's coupling.11Nsciescopu
Emergent localized states at the interface of a twofold PT -symmetric lattice
No full textⓒAmerican Physical Society. We consider the role of nontriviality resulting from a non-Hermitian Hamiltonian without band topology that conserves twofold PT symmetry assembled by interconnections between a PT -symmetric lattice and its timereversal partner. Twofold PT symmetry in the lattice produces additional surface exceptional points that play the role of new critical points, along with the bulk exceptional point. We show that there are two distinct regimes possessing symmetry-protected localized states of which localization lengths are robust against non-Hermiticity parameter. The states are demonstrated by numerical calculation of a quasi-one-dimensional ladder lattice and a two-dimensional bilayered square lattice.11Nscopu
Detection of the irradiated donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco)
Get PDFPhase-resolved VLT spectroscopy of the bursting low-mass X-ray binaries 4U 1636-536/V801 Ara and 4U 1735-444/V926 Sco is presented. Doppler images of the N iiiλ4640 Bowen transition reveal compact spots which we attribute to fluorescent emission from the donor star and enable us to define a new set of spectroscopic ephemerides. We measure Kem= 277 ± 22 and 226 ± 22 km s−1 from the N iii spots in V801 Ara and V926 Sco, respectively, which represent strict lower limits to the radial velocity semi-amplitude of the donor stars. Our new ephemerides provide confirmation that light-curve maxima in V801 Ara and likely V926 Sco occur at superior conjunction of the donor star and hence photometric modulation is caused by the visibility of the X-ray heated donor. The velocities of He iiλ4686 and the broad Bowen blend are strongly modulated with the orbital period, with phasing supporting emission dominated by the disc bulge. In addition, a reanalysis of burst oscillations in V801 Ara, using our spectroscopic T0, leads to K1= 90–113 km s−1. We also estimate the K-corrections for all possible disc flaring angles and present the first dynamical constraints on the masses of these X-ray bursters. These are K2= 360 ± 74 km s−1, f(M) = 0.76 ± 0.47 M⊙ and q= 0.21–0.34 for V801 Ara and K2= 298 ± 83 km s−1, f(M) = 0.53 ± 0.44 M⊙ and q= 0.05–0.41 for V926 Sco. Disc flaring angles α≥ 12° and q≃ 0.26–0.34 are favoured for V801 Ara whereas the lack of K1 constraint for V926 Sco prevents tight constraints on this system. Although both binaries seem to have intermediate inclinations, the larger equivalent width of the narrow N iii line in V801 Ara at phase 0.5 relative to phase 0 suggests that it has the higher inclination of the two
Perbandingan Harga Saham dan Volume Perdagangan Saham Sebelum dan Sesudah Pegumuman Anual Report Award (ARA)(Studi pada Perusahaan Go Public Pemenang ARA 2011-2012)
Get PDFPenelitian ini bertujuan untuk menguji apakah terdapat perbedaan harga saham dan volume perdagangan saham sebelum dan setelah pengumuman Annual Report Award (ARA). Sampel penelitian adalah seluruh perusahaan go public peraih ARA yang terdaftar di Bursa Efek Indonesia selama periode 2011-2012.
Data yang dianalisis adalah data sekunder seperti harga saham harian dan jumlah saham yang beredar. Penelitian ini menggunakan analisis event study untuk mengamati rata-rata harga saham dan rata-rata volume perdagangan saham pada periode tiga puluh hari sebelum dan tiga puluh hari sesudah peristiwa. Uji hipotesis dilakukan dengan uji paired sample t-test. Hasil penelitian ini menunjukan bahwa terdapat perbedaan harga saham dan volume perdagangan saham yang signifikan antara sebelum dan sesudah pengumuman ARA 2011-2012
KESADARAN DAN KETIDAKSADARAN TOKOH ARA DALAM CERPEN “INGATAN ARA” KARYA DEWI RIA UTARI: ANALISIS PSIKOLOGI SASTRA
Get PDFShiva, Nailis. 2018. "Awareness and Unconsciousness of Fig Characters in Short Story" Memory of Ara "by Dewi Ria Utari. Essay. 1st degree (S-1) in Indonesian Literature Language. Faculty of Cultural Sciences, Diponegoro University, Semarang. Advisor 1 Drs. Mulyo Hadi Purnomo, M. Hum. Advisor II Laura Andri R.M., S.S., M.A.
Short story "Memory of Ara" tells about personality changes experienced by the figure Ara from an extravers to become an intravers. The author tries to examine and express the awareness and unconsciousness experienced by the figure of Ara by using sequence theory, structural theory, and the literary psychology approach of Carl Gustav Jung. Sequence theory is used to determine the main character and find the sequence of stories. Structural theory is used to determine the short story intrinsic element which is focused on the character and characterization, plot, and background. The literary psychology approach of Carl Gustav Jung is used to express the awareness and unconsciousness experienced by Ara figures as well as to discover the personality changes of the figure of Ara. The method used in this study is a qualitative descriptive method using a structural approach and a literary psychology approach.
The results of the analysis of awareness and unconsciousness of the figure of Ara in the short story "Ara Memory" by Dewi Ria Utari are (1) personality changes of Ara characters from extravers to intravers, (2) awareness experienced by Ara figures, including mental attitudes consisting of extravers and intravers, functions soul which consists of feeling, thingking, sensing, and intuisting, as well as personal unconsciousness experienced by the figure Ara.
Keywords: short stories, structural, psychology, consciousness, unconsciousness
PROTOTYPE ARIEL ATOM GOKART (ArA-GO) SEBAGAI KENDARAAN PERFORMA TINGGI MULTIFUNGSI
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asli anak bangsa yang beredar di pasaran. Wacana mobil esemka dan mobil
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performa tinggi yang benar-benar terjangkau dipasaran.
PKM – Karsa Cipta berjudul “PERANCANGAN DAN PEMBUATAN
PROTOTYPE ARIEL ATOM GOKART (ArA-GO) SEBAGAI KENDARAAN
PERFORMA TINGGI MULTIFUNGSI”merupakan bentuk dari upaya untuk
mendukung majunya dunia otomotif di Indonesia. Dengan fungsi triple yaitu
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multifungsi yang memiliki daya guna maksimal untuk mendukung kemajuan dunia
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menekan biaya produksi sehingga tercipta kendaraan performa dan fungsi tinggi.
Rencana kegiatan kami dimulai dengan :
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sumpah pemuda mari kita berkarya untuk Indonesia
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