New gapped quantum phases for S=1 spin chain with D2h symmetry

We study different quantum phases in integer spin systems with on-site D2h=D2xZ2 and translation symmetry. We find four distinct non-trivial phases in S=1 spin chains despite they all have the same symmetry. All the four phases have gapped bulk excitations, doubly-degenerate end states and the doubly-degenerate entanglement spectrum. These non-trivial phases are examples of symmetry protected topological (SPT) phases introduced by Gu and Wen. One of the SPT phase correspond to the Haldane phase and the other three are new. These four SPT phases can be distinguished experimentally by their different response of the end states to weak external magnetic fields. According to Chen-Gu-Wen classification, the D2h symmetric spin chain can have totally 64 SPT phases that do not break any symmetry. Here we constructed seven nontrivial phases from the seven classes of nontrivial projective representations of D2h group. Four of these are found in S=1 spin chains and studied in this paper, and the other three may be realized in S=1 spin ladders or S=2 models.Comment: 15+ pages,5 figures, 9 table

Aqua­[6-carboxyl­ato-N′-(pyridin-2-yl­methyl­idene)pyridine-2-carbohydrazidato]copper(II) trihydrate

In the title compound, [Cu(C13H8N4O3)(H2O)]·3H2O, the complex molecule, except for the aqua ligand, is essentially planar [r.m.s. deviation = 0.034 (2) Å]. The coordination polyhedron of the Cu2+ cation is a square-pyramid, with the aqua ligand at the apex. The compound exhibits a three-dimensional structure, which is is stabilized by O—H⋯O and O—-H⋯N hydrogen bonds and π–π inter­actions [centroid–centroid distance = 2.987 (3) Å]

Circuit QED with a Giant Atom Coupling to Left-handed Superlattice Metamaterials

Giant atoms, where the dipole approximation ceases to be valid, allow us to observe unconventional quantum optical phenomena arising from interference and time-delay effects. Most previous studies consider giant atoms coupling to conventional materials with right-handed dispersion. In this study, we first investigate the quantum dynamics of a giant atom interacting with left-handed superlattice metamaterials. Different from those right-handed counterparts, the left-handed superlattices exhibit an asymmetric band gap generated by anomalous dispersive bands and Bragg scattering bands. First, by assuming that the giant atom is in resonance with the continuous dispersive energy band, spontaneous emission will undergo periodic enhancement or suppression due to the interference effect. At the resonant position, there is a significant discrepancy in the spontaneous decay rates between the upper and lower bands, which arises from the differences in group velocity. Second, we explore the non-Markovian dynamics of the giant atom by considering the frequency of the emitter outside the energy band, where bound states will be induced by the interference between two coupling points. By employing both analytical and numerical methods, we demonstrate that the steady atomic population will be periodically modulated, driven by variations in the size of the giant atom. The presence of asymmetric band edges leads to diverse interference dynamics. Finally, we consider the case of two identical emitters coupling to the waveguide and find that the energy within the two emitters undergoes exchange through the mechanism Rabi oscillations.Comment: 11 pages, 7 figure

Light-Matter interactions in Hofstadter lattice with the next-nearest neighbor couplings

The light-mater interactions for an emitter coupling to the bulk region of a Hofstadter lattice has recently investigated by De Bernardis \textit{et al.} [D. De Bernardis, Z.-P. Cian, I. Carusotto, M. Hafezi, and P. Rabl, \href{https://link.aps.org/doi/10.1103/PhysRevLett.126.103603}{Phys. Rev. Lett. 126, 103603 (2021)}]. We propose the light-mater interactions in an extended Hofstadter lattice with the next-nearest neighbor (NNN) couplings. Compared with the standard Hofstadter lattice, the NNN couplings break the mirror symmetry and the energy bands are not flat, i.e., dispersive with nonzero group velocity. In contrast to the study by De Bernardis \textit{et al.}, when a two-level emitter interacts with the bulk region of extended Hofstadter lattice, the emitter is no longer tapped by the coherent oscillations with the flat band, and can radiate photons unidirectional. The chiral mechanism stems from the broken parity symmetry. Both the radiation rate and the chirality periodically change with the emitter's coupling position. All of those particular features can be realized on the photonic lattice platform and may find potential application in chiral quantum information processing.Comment: 9 pages and 5 figure

Photorealistic Audio-driven Video Portraits

Video portraits are common in a variety of applications, such as videoconferencing, news broadcasting, and virtual education and training. We present a novel method to synthesize photorealistic video portraits for an input portrait video, automatically driven by a person’s voice. The main challenge in this task is the hallucination of plausible, photorealistic facial expressions from input speech audio. To address this challenge, we employ a parametric 3D face model represented by geometry, facial expression, illumination, etc., and learn a mapping from audio features to model parameters. The input source audio is first represented as a high-dimensional feature, which is used to predict facial expression parameters of the 3D face model. We then replace the expression parameters computed from the original target video with the predicted one, and rerender the reenacted face. Finally, we generate a photorealistic video portrait from the reenacted synthetic face sequence via a neural face renderer. One appealing feature of our approach is the generalization capability for various input speech audio, including synthetic speech audio from text-to-speech software. Extensive experimental results show that our approach outperforms previous general-purpose audio-driven video portrait methods. This includes a user study demonstrating that our results are rated as more realistic than previous methods

Effects of low-molecular-weight heparin and unfractionated heparin on traumatic disseminated intravascular coagulation

Purpose: To explore the effects of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) on traumatic disseminated  intravascular coagulation (DIC).Methods: A total of 77 cases of severe trauma (APACHE II score: 5 – 10) with DIC were collected and randomly assigned to one of three groups: LMWH treatment - 26 cases were subcutaneously injected with LMWH (75–150 units/kg/d); UFH treatment - 25 cases were subcutaneously  injected with UFH (100 – 250 units/kg/d); control - 26 cases supplemented with blood coagulation factor only. Daily mortality in the intensive care unit (ICU), hospitalization time, bleeding rate, thrombin time, prothrombin time, activated partial thromboplastin time, and levels of fibrinogen, antithrombin III (ATIII), and D-dimer were recorded and analyzed.Results: In ICU, LMWH and UFH treatments resulted in lower mortality than in the control group. In addition, hospitalization time was longer in patients treated with LMWH and UFH than in control patients. No significant  differences were found between LMWH-treated and control patients in terms of bleeding rate, but UFH-treated patients had lower bleeding rates than control patients. Multifactor analysis indicate a strong relationship between ATIII levels and bleeding rate.Conclusion: The results indicate that low-dose UFH and LMWH are effective options for the treatment of DIC.Keywords: Trauma, Disseminated intravascular coagulation, Unfractionated heparin, Low-molecularweight heparin, Fibrinogen, Antithrombi