A characterization of the unitary highest weight modules by Euclidean Jordan algebras

Let $\mathfrak{co}(J)$ be the conformal algebra of a simple Euclidean Jordan algebra $J$. We show that a (non-trivial) unitary highest weight $\mathfrak{co}(J)$-module has the smallest positive Gelfand-Kirillov dimension if and only if a certain quadratic relation is satisfied in the universal enveloping algebra $U(\mathfrak{co}(J)_{\mathbb{C}})$. In particular, we find an quadratic element in $U(\mathfrak{co}(J)_{\mathbb{C}})$. A prime ideal in $U(\mathfrak{co}(J)_{\mathbb{C}})$ equals the Joseph ideal if and only if it contains this quadratic element.Comment: 34pages, accepted by Journal of Lie Theor

Kazhdan-Lusztig right cells and associated varieties of highest weight modules

Let $\mathfrak{g}$ be a simple Lie algebra with a Weyl group $W$. Let $L_w$ be a simple module with highest weight $-w\rho-\rho$. By using a conjecture of Tanisaki, we show that there is a bijection between the right cells and associated varieties of highest weight modules with infinitesimal character $\rho$. When $L(\lambda)$ is a simple integral highest weight module of $\mathfrak{sl}(n,\mathbb{C})$ with the minimal Gelfand-Kirillov dimension $n-1$, we will show that its associated variety is irreducible. In particular, its associated variety will be given in the information of $\lambda$. When $L(\lambda)$ is a simple highest weight module of $\mathfrak{sl}(n,\mathbb{C})$ in a given parabolic category $\mathscr{O}^{\mathfrak{p}}$ with maximal Gelfand-Kirillov dimension, we will show that its associated variety is also irreducible.Comment: 9page

A combinatorial characterization of the annihilator varieties of highest weight modules for classical Lie algebras

Let $\mathfrak{g}$ be a classical Lie algebra. Let $L(\lambda)$ be a highest weight module of $\mathfrak{g}$ with highest weight $\lambda-\rho$, where $\rho$ is half the sum of positive roots. In 1985, Joseph proved that the associated variety of a primitive ideal is the Zariski closure of a nilpotent orbit in $\mathfrak{g}^*$. In this paper, we will give some combinatorial characterizations of the annihilator varieties of highest weight modules for classical Lie algebras. In fact, we will give two algorithms, i.e., bipartition algorithm and partition algorithm.Comment: 40page

Irreducible representations of GLn(C)\textrm{GL}_n(\mathbb{C}) of minimal Gelfand-Kirillov dimension

In this article, by studying the Bernstein degrees and Goldie rank polynomials, we establish a comparison between the irreducible representations of $G=\textrm{GL}_n(\mathbb{C})$ possessing the minimal Gelfand-Kirillov dimension and those induced from finite-dimensional representations of the maximal parabolic subgroup of $G$ of type $(n-1,1)$. We give the transition matrix between the two bases for the corresponding coherent families.Comment: To appear in Acta Mathematica Sinica, English Serie

Quantum PT-Phase Diagram in a Non-Hermitian Photonic Structure

Photonic structures have an inherent advantage to realize PT-phase transition through modulating the refractive index or gain-loss. However, quantum PT properties of these photonic systems have not been comprehensively studied yet. Here, in a bi-photonic structure with loss and gain simultaneously existing, we analytically obtained the quantum PT-phase diagram under the steady state condition. To characterize the PT-symmetry or -broken phase, we define an Hermitian exchange operator expressing the exchange between quadrature variables of two modes. If inputting several-photon Fock states into a PT-broken bi-waveguide splitting system, most photons will concentrate in the dominant waveguide with some state distributions. Quantum PT-phase diagram paves the way to the quantum state engineering, quantum interferences, and logic operations in non-Hermitian photonic systems.Comment: 6 pages, 3 figure