Holographic fermions in charged dilaton black branes

By imposing the relativistic boundary term and Lorentz violating that in the dilatonic black brane with a Lifshitz like IR geometry and _AdS4${\mathit{AdS}}_4$ boundary, we study the properties of the spectral functions of the fermions. We find that in the two fixed points, there are emergent Fermi-surface structures and many properties seem to be in agreement with that of Fermi liquid. Especially, the low energy behavior exhibits a linear dispersion relation. In addition, we also find that a holographic flat band also emerges in this background of the dilatonic black brane.     

Fractionally charged non-leaking dyons and fermions in a bag

We consider a fermion of chargee confined to a spherical bag with a Dirac monopole of strengthg at its centre. We find that the boundary conditions making the lowest angular momentum hamiltonian self-adjoint are characterized by a unitary matrixU, and the corresponding vacuum charge has a fractional part 2|eg|α/π where detU = -exp (2iα). Boundary conditions for conservation of helicity,CP, CT andPT are displayed. We demonstrate the possibility of a fractionally charged dyon whose interaction with a fermion conserves helicity. We also show thatthe simultaneous validity of helicity, CP, CT and PT requires integer vacuum charge.     

The quantum theory of the radiation from charged polarized fermions moving in crossed fields

The radiation of a charged Dirac particle, moving at relativistic velocity in orthogonal electric and magnetic fields (E H), is examined here. The formulas obtained are applicable for arbitrary orientation of the particle spin.     

Entropy correction of charged black hole via fermions tunneling beyond semi-classical approximation

Motivated by the idea of tunneling beyond semi-classical approximation of Majhi et al., we discuss entropy correction of Dirac particles tunneling from the Reissner-Nordstrm black hole with a global monopole. To get the corrections correctly, we regard the proportionality constants of quantum correction terms to the semi-classical term of action as the inverse of the square of the Planck Length but not that of the Planck Mass. Our study shows that corrections to the Bekenstein-Hawking entropy, namely the logarithmic term and the inverse area term, may be reproduced as the quantum effect is considered.     

受限一维无自旋费米子系统的性质研究

本文借助于一维自旋1/2-XXZ模型的Bethe-ansatz精确解, 利用局域密度近似(LDA), 讨论了谐振势中一维无自旋费米子的密度分布, 得出了ρ-u相图(这里的ρ为无量纲的粒子数密度 变量u为相互作用强度)对相图的分析表明, 随着原子密度和近邻相互作用的变化, 系统出现五个不同的混合量子相通过对热力学硬度S_ρ的计算, 发现其可作为体系的序参量, 其奇异点可用以度量受限体系中量子相变的发生     

Nonstandard mixing in a system of fermions

In this paper we continue to study the mixing of fermionic fields with different parities. Here we are interested in the manifestation of the latter in pion-nucleon scattering, which is analyzed for systems with particles having 3/2^± spins. Also, theoretical calculations are compared with experimental data from the partial analysis.     

Effective interactions in the charged colloidal system

In the charged colloidal system, with the aid of the hyper-sphere method, the effective interactions between two like-charged macro-ions are studied through Monte Carlo simulations. Numerical results show that the depletion interactions dominate the total Coulomb interactions in the region while the two macro-ions are near.     

Density modulation and superconductivity in a system of fermions

An antisymmetrized product of periodic density modulated one particle functions is investigated as a trial wave function for different local twobody forces. The model is compared with a BCS ground state. For some potentials a lower ground state energy has been found for the density modulated state. In lowest order cluster expansion forces with a hard core have been examined. A liquid-solid transition is indicated for³He at a density near the experimental value.     

带电胶体系统中的排空作用

用Monte Carlo模拟研究弱带电胶体系统的性质.在四维超球面欧氏空间中严格表示库仑作用的基础上，通过接受率法计算带电胶球间的排空势和排空力.研究了受限于两块平行带电平板之间、淹没于带电小胶球之中的一个或两个带电大胶球系统的排空作用，并通过与不带电的硬球系统相应结果的分析、对比，发现静电势能增强带电胶球之间的排空作用. 关键词： 超球面法 接受率方法 排空作用 Monte Carlo模拟     

BCS instability of a two-layer system of composite fermions

Pairing instability is considered for a two-layer electron system in a strong magnetic field with an even-fractional filling ν=1/(2m) (m is an integer) of the lowest Landau level in each of the layers. The limit of large distance d between the layers is analyzed. Microscopic analysis is carried out in the eikonal approximation in the composite-fermion formalism. It is found that the condition for pairing instability in this model is independent of d. Due to the marginal character of the composite-fermion system, pairing instability in the particle-particle (BCS) channel arises only for η<2 or η=2, but Mv ₀>43, where η and v ₀ are the parameters of the assumed electron-electron interaction, v∝v ₀/r ^η, and M is the band electron mass. In the particle-hole (isospin density wave) channel, instability is not observed.     

Thermodynamic limit of correlation functions in a system of gravitating fermions

We show that the correlation functions in a system of gravitating fermions converge as tempered distributions in the thermodynamic limit, if the system is not at the point of phase-transition. The densities converge to the density of the Thomas-Fermi-theory and are not correlated in the limit.     

A zero mode of the charged vortex-fermion system

We investigate the existence of zero modes of the electrically charged vortex-fermion system. This system can exist in (2 + 1) dimensions when a Chern-Simons term is present. For each odd n, where n is the topological charge of the vortex, we find a zero energy mode.     

Orbital quantization in a system of edge Dirac fermions in nanoperforated graphene

The dependence of the electric resistance R of nanoperforated graphene samples on the position of the Fermi level E _F, which is varied by the gate voltage V _g, has been studied. Nanoperforation has been performed by irradiating graphene samples on a Si/SiO₂ substrate by heavy (xenon) or light (helium) ions. A series of regular peaks have been revealed on the R(V _g) dependence at low temperatures in zero magnetic field. These peaks are attributed to the passage of E _F through an equidistant set of levels formed by orbitally quantized states of edge Dirac fermions rotating around each nanohole. The results are in agreement with the theory of edge states for massless Dirac fermions.     

Stability of the Bose system in Bose-Fermi mixture with attraction between bosons and fermions

An effective Hamiltonian for the Bose system in the mixture of ultracold atomic clouds of bosons and fermions is obtained by integrating out the Fermi degrees of freedom. An instability of the Bose system is found in the case of attractive interaction between components that is in good agreement with an experiment on the bosonic ⁸⁷Rb and fermionic ⁴⁰K mixture.