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Jian Zhou

Publications and source records attributed to Jian Zhou.

At least 343 records · Page 19Linked to original sources
arXiv2010

Transverse single spin asymmetry in the Drell-Yan process

We revisit the transverse single spin asymmetry in the angular distribution of a Drell-Yan dilepton pair. We study this asymmetry by using twist-3 collinear factorization, and we obtain the same result both in covariant gauge and in the light-cone gauge. Moreover, we have checked the electromagnetic gauge invariance of our calculation. Our final expression for the asymmetry differs from all the previous results given in the literature. The overall sign of this asymmetry is as important as the sign of the Sivers asymmetry in Drell-Yan.

hep-ph↗
arXiv2010

The electronic structures and magnetic properties of perovskite ruthenates from constrained orbital hybridization calculations

We introduce a method to analyze the effect of hybridization by shifting corresponding atomic levels using external potentials. Based on this approach, we study perovskite ruthenates,\ and unambiguously identify that the covalency between the \textit{A}-site cation and O ion will modify the Ru-O hybridization and change the density of state at Fermi level, consequently affect the magnetic properties significantly. We also study the effect of pressure and reveal that hydrostatic pressure has a small effect on the Ru-O-Ru bond angle of SrRuO$_{3}$, while it will decrease the Ru-O length and increase the band width significantly. Therefore, the magnetic ordering temperature will decrease monotonically with pressure.

cond-mat.mtrl-sci↗
arXiv2010

Realization and Properties of Biochemical-Computing Biocatalytic XOR Gate Based on Signal Change

We consider a realization of the XOR logic gate in a system involving two competing biocatalytic reactions, for which the logic-1 output is defined by these two processes causing a change in the optically detected signal. A model is developed for describing such systems in an approach suitable for evaluation of the analog noise amplification properties of the gate and optimization of its functioning. The initial data are fitted for gate quality evaluation within the developed model, and then modifications are proposed and experimentally realized for improving the gate functioning.

cond-mat.soft↗
arXiv2010

Enzymatic AND Logic Gates Operated Under Conditions Characteristic of Biomedical Applications

Experimental and theoretical analyses of the lactate dehydrogenase and glutathione reductase based enzymatic AND logic gates in which the enzymes and their substrates serve as logic inputs are performed. These two systems are examples of the novel, previously unexplored, class of biochemical logic gates that illustrate potential biomedical applications of biochemical logic. They are characterized by input concentrations at logic 0 and 1 states corresponding to normal and abnormal physiological conditions. Our analysis shows that the logic gates under investigation have similar noise characteristics. Both significantly amplify random noise present in inputs, however we establish that for realistic widths of the input noise distributions, it is still possible to differentiate between the logic 0 and 1 states of the output. This indicates that reliable detection of abnormal biomedical conditions is indeed possible with such enzyme-logic systems.

cond-mat.soft↗
arXiv2010

The rationality problem for finite subgroups of GL_4(Q)

Let $G$ be a finite subgroup of $GL_4(\bm{Q})$. The group $G$ induces an action on $\bm{Q}(x_1,x_2,x_3,x_4)$, the rational function field of four variables over $\bm{Q}$. Theorem. The fixed subfield $\bm{Q}(x_1,x_2,x_3,x_4)^G:=\{f\in\bm{Q}(x_1,x_2,x_3,x_4):σ\cdot f=f$ for any $σ\in G\}$ is rational (i.e.\ purely transcendental) over $\bm{Q}$, except for two groups which are images of faithful representations of $C_8$ and $C_3\rtimes C_8$ into $GL_4(\bm{Q})$ (both fixed fields for these two exceptional cases are not rational over $\bm{Q}$). There are precisely 227 such groups in $GL_4(\bm{Q})$ up to conjugation; the answers to the rationality problem for most of them were proved by Kitayama and Yamasaki \cite{KY} except for four cases. We solve these four cases left unsettled by Kitayama and Yamasaki; thus the whole problem is solved completely.

math.AG↗
arXiv2010

Noether's problem for \hat{S}_4 and \hat{S}_5

Let $k$ be a field, $G$ be a finite group and $k(x_g:g\in G)$ be the rational function field over $k$, on which $G$ acts by $k$-automorphisms defined by $h\cdot x_g=x_{hg}$ for any $g,h\in G$. Noether's problem asks whether the fixed subfield $k(G):=k(x_g:g\in G)^G$ is $k$-rational, i.e.\ purely transcendental over $k$. If $\widehat{S_n}$ is the double cover of the symmetric group $S_n$, in which the liftings of transpositions and products of disjoint transpositions are of order $4$, Serre shows that $\bm{Q}(\widehat{S_4})$ and $\bm{Q}(\widehat{S_5})$ are not $\bm{Q}$-rational. We will prove that, if $k$ is a field such that $\fn{char} k \neq 2, 3$, and $k(ζ_8)$ is a cyclic extension of $k$, then $k(\widehat{S_4})$ is $k$-rational. If it is assumed furthermore that $\fn{char}k=0$, then $k(\widehat{S_5})$ is also $k$-rational.

math.AG↗
arXiv2010

Twist-three Fragmentation Function Contribution to the Single Spin Asymmetry in pp Collisions

We study the twist-three fragmentation function contribution to the single transverse spin asymmetries in inclusive hadron production in pp collisions, pp->h+X. In particular, we evaluate the so-called derivative contribution which dominates the spin asymmetry in the forward direction of the polarized proton. With certain parametrizations for the twist-three fragmentation function, we estimate its contribution to the asymmetry of pi0 production at RHIC energy. We find that the contribution is sizable and might be responsible for the big difference between the asymmetries in eta and pi0 productions observed by the STAR collaboration at RHIC.

hep-ph↗
arXiv2010

A Proof of the Full Marino-Vafa Conjecture

We present a proof of the full Mariño-Vafa Conjecture that identifies certain open string invariants of the resolved conifold with the Chern-Simons knot invariant of the unknot, i.e. the quantum dimensions.

math.AG↗
arXiv2010

Open String Invariants and Mirror Curve of the Resolved Conifold

For the resolved conifold with one outer D-brane in arbitrary framing, we present some results for the open string partition functions obtained by some operator manipulations. We prove some conjectures by Aganagic-Vafa and Aganagic-Klemm-Vafa that relates such invariants to the mirror curve of the resolved conifold. This establishes local mirror symmetry for the resolved confolds for holomorphic disc invariants. We also verify an integrality conjecture of such invariants by Ooguri-Vafa in this case and present closed formulas for some Ooguri-Vafa type invariants in genus 0 and arbitrary genera.

math.AG↗
arXiv2009

Local Mirror Symmetry for the Topological Vertex

For three-partition triple Hodge integrals related to the topological vertex, we derive Eynard-Orantin type recursion relations from the cut-and-join equation. This establishes a version of local mirror symmetry for the local $C^3$ geometry with three D-branes, as proposed by Marino and Bouchard-Klemm-Marino-Pasquetti.

math.AG↗
arXiv2009

Local Mirror Symmetry for One-Legged Topological Vertex

We prove the Bouchard-Mariño Conjecture for the framed one-legged topological vertex by deriving the Eynard-Orantin type recursion relations from the cut-and-join equation satisfied by the relevant triple Hodge integrals. This establishes a version of local mirror symmetry for the local $C^3$ geometry with one $D$-brane.

math.AG↗
arXiv2009

Novel electronic and magnetic properties of BN sheet decorated with hydrogen and fluorine

First principles calculations based on density functional theory reveal some unusual properties of BN sheet functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN sheet significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN sheet can be tuned from 4.7 eV to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending upon surface coverage. (2) Unlike graphene, BN sheet has hetero-atomic composition, when co-decorated with H and F, it can lead to anisotropic structures with rich electronic and magnetic properties. (3) Unlike graphene, BN sheets can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending upon how the surface is functionalized. (4) The stability of magnetic coupling of functionalized BN sheet can be further modulated by applying external strain. Our study highlights the potential of functionalized BN sheets for novel applications.

cond-mat.mtrl-sci↗
arXiv2009

Transverse momentum dependent quark distributions and polarized Drell-Yan processes

We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further calculate the angular distribution of the Drell-Yan lepton pair production with polarized beams and present the results in terms of the collinear twist-three quark-gluon correlation functions. In the intermediate transverse momentum region, we find that the two pproaches: the collinear factorization and the transverse momentum dependent factorization approaches are consistent in the description of the lepton pair angular distributions.

hep-ph↗
arXiv2009

Enhanced spin-orbit coupling in hydrogenated and fluorinated graphenes studied from first principles

The spin-orbit couplings (SOCs) of hydrogenated and fluorinated graphenes are calculated from the first principles method. It is found that the SOC-induced band splittings near their Fermi energies can be significantly enhanced to the order of 10$^{-2}$ eV from the original about 10$^{-6}$ eV of the pure raphene, which is comparable to those found in the diamond and even the archetypal semiconductors. And two different mechanisms are proposed to explain the SOC enhancements in these two systems. The huge SOC enhancements are found to come not only from the sp$^3$ hybridization of carbon atoms, but also from the larger intrinsic SOC of the fluorine atom than the carbon one. We hope many interesting phenomena caused by the SOCs (e.g. the spin Hall effect) can be observed experimentally in these systems.

cond-mat.mes-hall↗
arXiv2009

Crepant Resolutions, Quivers and GW/NCDT Duality

We propose a conjecture that relates some local Gromov-Witten invariants of some crepant resolutions of Calabi-Yau 3-folds with isolated singularities with some Donaldson-Thomas type invariants of the moduli spaces of representations of some quivers with potentials.

math.AG↗