arXiv subjects

Xin-Hui Zhang

Publications and source records attributed to Xin-Hui Zhang.

12 recordsLinked to original sources

arXiv2018

Bloch bound state of spin-orbit-coupled fermions in an optical lattice

Understanding fundamentals of few-body physics provides an interesting bottom-up approach for the clarification of many-body properties. The remarkable experimental progress in realizing spin-orbit coupling (SOC) in optical Raman lattices offers a renewed thrust towards discovering novel few-body features induced by the interplay between SOC and optical lattices. Using the Wilson renormalization method to account for high-band effects, we study the low-energy two-body scattering processes of spin-$1/2$ fermions in spin-orbit coupled optical lattices. We demonstrate that, under weak SOC, adding a small lattice potential would destabilize shallow two-body bound states, contrary to conventional wisdom. On the other hand, when lattice is sufficiently deep, two-body bound states are always stabilized by increasing the lattice depth. This intriguing non-monotonic behavior of the bound-state stability derives from the competition between SOC and optical lattices, and can be explained by analyzing the low-energy density of states. We also discuss the impact of high-band effects on such a behavior, as well as potential experimental detections.

cond-mat.quant-gas↗

arXiv2010

Entropy of entangled three-level atoms interacting with entangled cavity fields: entanglement swapping

The dynamics of an entangled atomic system in a partial interaction with entangled cavity fields, characterizing an entanglement swapping, have been studied through the use of Von Neuman entropy. We consider the interaction via two-photon process given by a full microscopical Hamiltonian approach. The explicit expression of the entropy is obtained, wherewith we estimated the largest period. The numerical simulation of the entropy of the entangled atomic and cavity systems shows that its time evolution presents multi-periodicity. The effects of detuning parameter on the period and the amplitude of the entropy are also discussed.

quant-ph↗

arXiv2008

Localization of fermionic fields on braneworlds with bulk tachyon matter

Recently, Pal and Skar in [arXiv:hep-th/0701266] proposed a mechanism to arise the warped braneworld models from bulk tachyon matter, which are endowed with a thin brane and a thick brane. In this framework, we investigate localization of fermionic fields on these branes. As in the 1/2 spin case, the field can be localized on both the thin and thick branes with inclusion of scalar background. In the 3/2 spin extension, the general supergravity action coupled to chiral supermultiplets is considered to produce the localization on both the branes as a result.

hep-th↗

arXiv2008

Localization of Matters on Pure Geometrical Thick Branes

In the literatures, several types of thick smooth brane configurations in a pure geometric Weyl integrable 5-dimensional space time have been presented. The Weyl geometry is a non-Riemannian modification of 5-dimensional Kaluza--Klein (KK) theory. All these thick brane solutions preserve 4-dimensional Poincaré invariance, and some of them break $Z_2$--symmetry along the extra dimension. In this paper, we study localization of various matter fields on these pure geometrical thick branes, which also localize the graviton. We present the shape of the potential of the corresponding Schr$\mathrm{\ddot{o}}$dinger problem and obtain the lowest KK mode. It is showed that, for both spin 0 scalars and spin 1 vectors, there exists a continuum gapless spectrum of KK states with $m^2>0$. But only the massless mode of scalars is found to be normalizable on the brane. However, for the massless left or right chiral fermion localization, there must be some kind of Yukawa coupling. For a special coupling, there exist a series of discrete massive KK modes with $m^2 >0$. It is also showed that for a given coupling constant only one of the massless chiral modes is localized on the branes.

hep-th↗

arXiv2007

Self-Dual Vortices in the Fractional Quantum Hall System

Based on the $ϕ$-mapping theory, we obtain an exact Bogomol'nyi self-dual equation with a topological term, which is ignored in traditional self-dual equation, in the fractional quantum Hall system. It is revealed that there exist self-dual vortices in the system. We investigate the inner topological structure of the self-dual vortices and show that the topological charges of the vortices are quantized by Hopf indices and Brouwer degrees. Furthermore, we study the branch processes in detail. The vortices are found generating or annihilating at the limit points and encountering, splitting or merging at the bifurcation points of the vector field $\vecϕ$.

hep-th↗

arXiv2007

Detecting Extra Dimension by Helium-like Ions

Considering that gravitational force might deviate from Newton's inverse-square law and become much stronger in small scale, we present a method to detect the possible existence of extra dimensions in the ADD model. By making use of an effective variational wave function, we obtain the nonrelativistic ground energy of a helium atom and its isoelectronic sequence. Based on these results, we calculate gravity correction of the ADD model. Our calculation may provide a rough estimation about the magnitude of the corresponding frequencies which could be measured in later experiments.

hep-th↗

arXiv2007

Fermions in Self-dual Vortex Background on a String-like Defect

By using the self-dual vortex background on extra two-dimensional Riemann surfaces in 5+1 dimensions, the localization mechanism of bulk fermions on a string-like defect with the exponentially decreasing warp-factor is obtained. We give the conditions under which localized spin 1/2 and 3/2 fermions can be obtained.

hep-th↗

arXiv2007

Topological Vortex Lines in Two-Gap Superconductor

Based on the U(1) gauge potential decomposition theory and the $ϕ$-mapping method, we study the vortex lines in two-gap superconductor and obtain the condition, under which the vortices can carry an arbitrary fraction of magnetic flux. It has been pointed out that the Chern-Simon action is a topological invariant, which is just the total sum of all the self-linking numbers and all the linking numbers of the knot family.

cond-mat.supr-con↗

arXiv2007

Topological Excitation in Skyrme Theory

Based on the $ϕ$-mapping topological current theory and the decomposition of gauge potential theory, we investigate knotted vortex lines and monopoles in Skyrme theory and simply discuss the branch processes (splitting, merging and intersection) during the evolution of the monopoles.

hep-th↗

arXiv2007

Knotted Solitons in a Charged Two-Condensate Bose System

By making use of the decomposition of U(1) gauge potential theory and the ϕmapping method, we propose that a charged two-condensate Bose system possesses vortex lines and two classes of knotted solitons. The topological charges of the vortex lines are characterized by the Hopf indices and the Brower degrees of ϕ-mapping, and the knotted solitons are described by the nontrivial Hopf invariant and the BF action, respectively.

cond-mat.supr-con↗

arXiv2007

Novel Topological Invariant in the U(1) Gauge Field Theory

Based on the decomposition of U(1) gauge potential theory and the $ϕ$-mapping topological current theory, the three-dimensional knot invariant and a four-dimensional new topological invariant are discussed in the U(1) gauge field.

hep-th↗

arXiv2007

Topological aspect of black hole with Skyrme hair

Based on the $ϕ$-mapping topological current theory, we show that the presence of the black hole leaves fractional baryon charge outside the horizon in the Einstein-Skyrme theory. A topological current is derived from the Einstein-Skyrme system, which corresponds to the monopoles around the black hole. The branch process (splitting, merging and intersection) is simply discussed during the evolution of the monopoles.

hep-th↗