Signatures of quantum criticality in the complex inverse temperature plane

Concepts of complex partition functions and the Fisher zeros provide intrinsic statistical mechanisms for finite temperature and real time dynamical phase transitions. We extend the utility of these complexifications to quantum phase transitions. We exactly identify different Fisher zeros on lines or closed curves and elucidate their correspondence with domain-wall excitation or confined meson for the one-dimensional transverse field Ising model. The crossover behavior of Fisher zeros provides a fascinating picture for criticality near the quantum phase transition, where the excitation energy scales are quantitatively determined. We further confirm our results by tensor network calculation and demonstrate a clear signal of deconfined meson excitation from the breaking of the closed zero curves. Our results unambiguously show significant features of the Fisher zeros for a quantum phase transition and open up a new route to explore quantum criticality.Comment: 6 pages, 4 figure

Three-Leaf Dart-Shaped Single-Crystal BN Formation Promoted by Surface Oxygen

Two-dimensional hexagonal boron nitride (h-BN) single crystals with various shapes have been synthesized by chemical vapor deposition over the past several years. Here we report the formation of three-leaf dart (3LD)-shaped single crystals of h-BN on Cu foil by atmospheric-pressure chemical vapor deposition. The leaves of the 3LD-shaped h-BN are as long as 18 {\mu}m and their edges are smooth armchair on one side and stepped armchair on the other. Careful analysis revealed that surface oxygen plays an important role in the formation of the 3LD shape. Oxygen suppressed h-BN nucleation by passivating Cu surface active sites and lowered the edge attachment energy, which caused the growth kinetics to change to a diffusion-controlled mode.Comment: 7 pages,6 figure

Global characterization of the root transcriptome of a wild species of rice, Oryza longistaminata, by deep sequencing

<p>Abstract</p> <p>Background</p> <p><it>Oryza longistaminata</it>, an AA genome type (2 n = 24), originates from Africa and is closely related to Asian cultivated rice (<it>O. sativa L</it>.). It contains various valuable traits with respect to tolerance to biotic and abiotic stress, QTLs with agronomically important traits and high ability to use nitrogen efficiently (NUE). However, only limited genomic or transcriptomic data of <it>O. longistaminata </it>are currently available.</p> <p>Results</p> <p>In this study we present the first comprehensive characterization of the <it>O. longistaminata </it>root transcriptome using 454 pyrosequencing. One sequencing run using a normalized cDNA library from <it>O. longistaminata </it>roots adapted to low N conditions generated 337,830 reads, which assembled into 41,189 contigs and 30,178 singletons. By similarity search against protein databases, putative functions were assigned to over 34,510 uni-ESTs. Comparison with ESTs derived from cultivated rice collections revealed expressed genes across different plant species, however 16.7% of the <it>O. longistaminata </it>ESTs had not been detected as expressed in <it>O. sativa</it>. Additionally, 15.7% had no significant similarity to known sequences. RT-PCR and Southern blot analyses confirmed the expression of selected novel transcripts in <it>O. longistaminata</it>.</p> <p>Conclusion</p> <p>Our results show that one run using a Genome Sequencer FLX from 454 Life Science/Roche generates sufficient genomic information for adequate de novo assembly of a large number of transcripts in a wild rice species, <it>O. longistaminata</it>. The generated sequence data are publicly available and will facilitate gene discovery in <it>O. longistaminata </it>and rice functional genomic studies. The large number of abundant of novel ESTs suggests different metabolic activity in <it>O. longistaminata </it>roots in comparison to <it>O. sativa </it>roots.</p

Choked accretion onto Kerr-Sen black holes in Einstein-Maxwell-Dilation-Axion gravity

We study the choked accretion process of an ultrarelativistic fluid onto axisymmetric Kerr-Sen black holes in Einstein-Maxwell-Dilation-Axion theory. We calculate the solution describing the velocity potential $\Phi$ of a stationary, irrotational fluid, which satisfies the stiff equation of state and draw the streamlined diagram of the quadrupolar flow solution. We investigate how parameters affect the solution's coefficient and stagnation point. The injection rate, ejection rate, and critical angle are discussed in detail at the end of the article. If the inner and outer event horizons of the black hole are satisfied, then we can find that the ratio of the ejection rate to the setting rate increases with an increase in the dilation parameter.Comment: 25pages,10 figure

Thermal conduction simulation based on reconstruction digital rocks with respect to fractures

Effective thermal conductivity (ETC), as a necessary parameter in the thermal properties of rock, is affected by the pore structure and the thermal conduction conditions. To evaluate the effect of fractures and saturated fluids on sandstone’s thermal conductivity, we simulated thermal conduction along three orthogonal (X, Y, and Z) directions under air- and water-saturated conditions on reconstructed digital rocks with different fractures. The results show that the temperature distribution is separated by the fracture. The significant difference between the thermal conductivities of solid and fluid is the primary factor influencing the temperature distribution, and the thermal conduction mainly depends on the solid phase. A nonlinear reduction of ETC is observed with increasing fracture length and angle. Only when the values of the fracture length and angle are large, a negative effect of fracture aperture on the ETC is apparent. Based on the partial least squares (PLS) regression method, the fluid thermal conductivity shows the greatest positive influence on the ETC value. The fracture length and angle are two other factors significantly influencing the ETC, while the impact of fracture aperture may be ignored. We obtained a predictive equation of ETC which considers the related parameters of digital rocks, including the fracture length, fracture aperture, angle between the fracture and the heat flux direction, porosity, and the thermal conductivity of saturated fluid