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Xiaosen Han

Publications and source records attributed to Xiaosen Han.

17 recordsLinked to original sources
arXiv2025

Vortex Solutions for A Mixed Boundary-Value Problem in the Abelian-Higgs Model with A Neutral Scalar Field

Vortices represent a class of topological solitons arising in gauge theories coupled with complex scalar fields, holding significant importance across various domains of modern physics. In this paper we establish the existence of vortex solutions for a mixed boundary-value problem derived from the Abelian-Higgs model incorporating a neutral scalar field, a system recently investigated by Eto, Peterson et al. [7]. By synergistically combining the shooting method with the Schauder fixed-point theorem, we derive sharp analytical criteria that delineate the Abelian vortex phase from the non-Abelian one. We also rigorously establish the monotonicity, uniform boundedness, and precise asymptotic behavior of the vortex profile functions. Our results provide rigorous confirmation of numerical observations regarding the phase boundary between these distinct vortex types.

math.AP↗
arXiv2023

Existence of $U(1)$ Gauged Q-balls for A Field Model with Sixth-order Potential

Q-balls are non-topological solitons in a large family of field theories. We focus on the existence of $U(1)$ gauged Q-balls for a field theory with sixth-order potential. The problem can be reduced to proving the existence of critical points for some indefinite functional. For this, we use a constrained minimization approach to obtain the existence of critical points. Moreover, we establish some qualitative properties of the Q-ball solution, such as monotonicity, boundedness and asymptotic behavior.

math-ph↗
arXiv2021

Existence of global vortices in a class of Ginzburg-Landau models

In this paper, the two-component Ginzburg-Landau (TCGL) model, which is an important research object in mathematics and physics of two scalar fields with $U(1)\times U(1)$ symmetry, is studied in detail by the shooting method and the fixed point theorem, which contains two cases: single vacuum expectation value (1VEV) and two vacuum expectation values (2VEV). This represents two different physical states: superconductivity-normal state and superconductivity superconductivity state, and we prove the existence, uniqueness, asymptotic properties and quantization of the solutions to these two boundary value problems.

math.AP↗
arXiv2019

Coexisting Vortices and Antivortices Generated by Dually Gauged Harmonic Maps

In this paper we first formulate a dually gauged harmonic map model, suggested from a product Abelian Higgs field theory arising in impurity-inspired field theories, and obtain a new BPS system of equations governing coexisting vortices and antivortices, which are topologically characterized by the first Chern class of the underlying Hermitian bundle and the Thom class of the associated dual bundle. We then establish existence and uniqueness theorems for such vortices. For the equations over a compact surface, we obtain necessary and sufficient conditions for the existence of solutions. For the equations over the full plane, we obtain all finite-energy solutions. Besides, we also present precise expressions giving the values of various physical quantities of the solutions, including magnetic charges and energies, in terms of the total numbers of vortices and antivortices, of two species, and the coupling parameters involved.

math-ph↗
arXiv2018

Multiple Solutions for the Non-Abelian Chern--Simons--Higgs Vortex Equations

In this paper we study the existence of multiple solutions for the non-Abelian Chern--Simons--Higgs $(N\times N)$-system: \[ Δu_i=λ\left(\sum_{j=1}^N\sum_{k=1}^N K_{kj}K_{ji}\re^{u_j}\re^{u_k}-\sum_{j=1}^N K_{ji}\re^{u_j}\right)+4π\sum_{j=1}^{n_i}δ_{p_{ij}},\quad i=1,\dots, N; \] over a doubly periodic domain $Ω$, with coupling matrix $K$ given by the Cartan matrix of $SU(N+1),$ (see \eqref{k1} below). Here, $λ>0$ is the coupling parameter, $δ_p$ is the Dirac measure with pole at $p$ and $n_i\in \mathbb{N},$ for $i=1, \dots, N.$ When $N=1, 2$ many results are now available for the periodic solvability of such system and provide the existence of different classes of solutions known as: topological, non-topological, mixed and blow-up type. On the contrary for $N\ge 3,$ only recently in \cite{haya1} the authors managed to obtain the existence of one doubly periodic solution via a minimisation procedure, in the spirit of \cite{nota} . Our main contribution in this paper is to show (as in \cite{nota}) that actually the given system admits a second doubly periodic solutions of "Mountain-pass" type, provided that $3\le N\le 5$. Note that the existence of multiple solutions is relevant from the physical point of view. Indeed, it implies the co-existence of different non-Abelian Chern--Simons condensates sharing the same set (assigned component-wise) of vortex points, energy and fluxes. The main difficulty to overcome is to attain a "compactness" property encompassed by the so called Palais--Smale condition for the corresponding "action" functional, whose validity remains still open for $N\ge 6$.

math.AP↗
arXiv2016

Non-topological Vortex Configurations in the ABJM Model

In this paper we study the existence of vortex-type solutions for a system of self-dual equations deduced from the mass-deformed Aharony--Bergman--Jafferis--Maldacena (ABJM) model. The governing equations, derived by Mohammed, Murugan, and Nastse under suitable ansatz involving fuzzy sphere matrices, have the new feature that they can support only non-topological vortex solutions. After transforming the self-dual equations into a nonlinear elliptic $2\times 2$ system we prove first an existence result by means of a perturbation argument based on a new and appropriate scaling for the solutions. Subsequently, we prove a more complete existence result by using a dynamical analysis together with a blow-up argument. In this way we establish that, any positive energy level is attained by a 1-parameter family of vortex solutions which also correspond to (constraint) energy minimizers. In other words, we register the exceptional fact in a BPS-setting that, neither a "quantization" effect nor an energy gap is induced upon the system by the rigid "critical" coupling of the self-dual regime.

math.AP↗
arXiv2015

Topologically Stratified Energy Minimizers in a Product Abelian Field Theory

We study a recently developed product Abelian gauge field theory by Tong and Wong hosting magnetic impurities. We first obtain a necessary and sufficient condition for the existence of a unique solution realizing such impurities in the form of multiple vortices. We next reformulate the theory into an extended model that allows the coexistence of vortices and anti-vortices. The two Abelian gauge fields in the model induce two species of magnetic vortex-lines resulting from $N_s$ vortices and $P_s$ anti-vortices ($s=1,2$) realized as the zeros and poles of two complex-valued Higgs fields, respectively. An existence theorem is established for the governing equations over a compact Riemann surface $S$ which states that a solution with prescribed $N_1, N_2$ vortices and $P_1,P_2$ anti-vortices of two designated species exists if and only if the inequalities \[ \left|N_1+N_2-(P_1+P_2)\right|<\frac{|S|}π,\quad \left|N_1+2N_2-(P_1+2P_2)\right|<\frac{|S|}π, \] hold simultaneously, which give bounds for the `differences' of the vortex and anti-vortex numbers in terms of the total surface area of $S$. The minimum energy of these solutions is shown to assume the explicit value \[ E= 4π(N_1+N_2+P_1+P_2), \] given in terms of several topological invariants, measuring the total tension of the vortex-lines.

math-ph↗
arXiv2015

Relativistic Chern--Simons--Higgs Vortex Equations

An existence theorem is established for the solutions to the non-Abelian relativistic Chern--Simons--Higgs vortex equations over a doubly periodic domain when the gauge group $G$ assumes the most general and important prototype form, $G=SU(N)$

math.AP↗
arXiv2015

Resolution of Chern--Simons--Higgs Vortex Equations

It is well known that the presence of multiple constraints of non-Abelian relativisitic Chern--Simons--Higgs vortex equations makes it difficult to develop an existence theory when the underlying Cartan matrix $K$ of the equations is that of a general simple Lie algebra and the strongest result in the literature so far is when the Cartan subalgebra is of dimension 2. In this paper we overcome this difficulty by implicitly resolving the multiple constraints using a degree-theorem argument, utilizing a key positivity property of the inverse of the Cartan matrix deduced in an earlier work of Lusztig and Tits, which enables a process that converts the equality constraints to inequality constraints in the variational formalism. Thus this work establishes a general existence theorem which settles a long-standing open problem in the field regarding the general solvability of the equations.

math-ph↗
arXiv2013

Existence theorems for non-Abelian Chern--Simons--Higgs vortices with flavor

In this paper we establish the existence of vortex solutions for a Chern--Simons--Higgs model with gauge group $SU(N) \times U(1)$ and flavor SU(N), these symmetries ensuring the existence of genuine non-Abelian vortices through a color-flavor locking. Under a suitable ansatz we reduce the problem to a $2\times 2$ system of nonlinear elliptic equations with exponential terms. We study this system over the full plane and over a doubly periodic domain, respectively. For the planar case we use a variational argument to establish the existence result and derive the decay estimates of the solutions. Over the doubly periodic domain we show that the system admits at least two gauge-distinct solutions carrying the same physical energy by using a constrained minimization approach and the mountain-pass theorem. In both cases we get the quantized vortex magnetic fluxes and electric charges.

math.AP↗
arXiv2013

Chern--Simons Vortices in the Gudnason Model

We present a series of existence theorems for multiple vortex solutions in the Gudnason model of the ${\cal N}=2$ supersymmetric field theory where non-Abelian gauge fields are governed by the pure Chern--Simons dynamics at dual levels and realized as the solutions of a system of elliptic equations with exponential nonlinearity over two-dimensional domains. In the full plane situation, our method utilizes a minimization approach, and in the doubly periodic situation, we employ an-inequality constrained minimization approach. In the latter case, we also obtain sufficient conditions under which we show that there exist at least two gauge-distinct solutions for any prescribed distribution of vortices. In other words, there are distinct solutions with identical vortex distribution, energy, and electric and magnetic charges.

math.AP↗
arXiv2013

A Sharp Existence Theorem for Vortices in the Theory of Branes

We investigate the BPS equations arising from the theory of multi-intersection of D-branes. By using the direct minimization method, we establish sharp existence and uniqueness theorems for multiple vortex solutions of the BPS equations over a doubly periodic domain and over the full plane, respectively. In particular, we obtain an explicit necessary and sufficient condition for the existence of a unique solution for the doubly periodic domain case.

math-ph↗
arXiv2012

Doubly Periodic Self-Dual Vortices for a Relativistic Non-Abelian Chern--Simons Model

In this paper we establish a multiplicity result concerning the existence of doubly periodic solutions for a $2\times2$ nonlinear elliptic system arising in the study of self-dual non-Abelian Chern--Simons vortices. We show that the given system admits at least two solutions when the Chern--Simons coupling parameter $κ>0$ is sufficiently small; while no solutions exist for $κ>0$ sufficiently large. As in [36] we use a variational formulation of the problem. Thus, we obtain a first solution via a (local) minimization method and show that it is asymptotically gauge-equivalent to the (broken) principal embedding vacuum of the system, as $κ\to 0$. Then we obtain the second solution by a min-max procedure of "mountain pass" type.

math-ph↗
arXiv2012

Existence Theorems for Vortices in the Aharony--Bergman--Jaferis--Maldacena Model

A series of sharp existence and uniqueness theorems are established for the multiple vortex solutions in the supersymmetric Chern--Simons--Higgs theory formalism of Aharony, Bergman, Jaferis, and Maldacena, for which the Higgs bosons and Dirac fermions lie in the bifundamental representation of the general gauge symmetry group $U(N)\times U(N)$. The governing equations are of the BPS type and derived by Kim, Kim, Kwon, and Nakajima in the mass-deformed framework labeled by a continuous parameter.

math-ph↗
arXiv2012

The Existence of Multi-vortices for a Generalized Self-dual Chern-Simons Model

In this paper we establish the existence of multi-vortices for a generalized self-dual Chern--Simons model. Doubly periodic vortices, topological and non-topological vortex solutions are constructed for this model. For the existence of doubly periodic vortex solutions, we establish an explicitly necessary and sufficient condition. It is difficult to get topological multi-vortex solutions due to the non-canonical structure of the equations. We overcome this difficulty by constructing a suitable sub-solution for the reduced equation. This technique maybe applied to the problems with similar structures. For the existence of non-topological solutions we use a shooting argument.

math-ph↗
arXiv2012

Existence of Doubly Periodic Vortices in a Generalized Chern--Simons Model

We establish an existence theorem for the doubly periodic vortices in a generalized self-dual Chern--Simons model. We show that there exists a critical value of the coupling parameter such that there exits self-dual doubly periodic vortex solutions for the generalized self-dual Chern--Simons equation if and only if the coupling parameter is less than or equal to the value. The energy, magnetic flux, and electric charge associated to the field configurations are all specifically quantized. By the solutions obtained for this generalized self-dual Chern--Simons equation we can also construct doubly periodic vortex solutions to a generalized self-dual Abelian Higgs equation.

math-ph↗