Pengaruh Keahlian Akuntansi dan Keuangan Komite Audit dan Dewan Komisaris terhadap Manajemen Laba

This study examines whether the proportion of members of the audit committee and board of commissioner with accounting and/or financial expertise reduces earnings management. Accounting expertise is separated to financial expertise because accounting expertise is assumed to be able to cope with more earnings management while financial expertise focuses more on the financial management of company's operations. By using panel data, this study finds that the existence of members of audit committee and board of commissioner with accounting expertise or financial expertise do not have a negative effect on earnings management. However, the existence of both expertises on members of board of commissioner reduces earnings management, while that is not the case for audit committee.---Penelitian ini bertujuan untuk menguji apakah proporsi anggota komite audit dan anggota dewan komisaris yang memiliki keahlian akuntansi dan/atau keuangan mengurangi terjadinya manajemen laba Perusahaan. Pemisahan keahlian akuntansi dan keahlian keuangan dilakukan karena keahlian akuntansi diasumsikan lebih mampu mengatasi manajemen laba sementara keahlian keuangan lebih fokus pada pengelolaan keuangan dalam operasional Perusahaan. Dengan menggunakan panel data, penelitian ini menemukan bahwa anggota komite audit dan anggota dewan komisaris yang memiliki keahlian akuntansi atau keahlian keuangan tidak berpengaruh negatif terhadap manajemen laba. Namun, keberadaan kedua keahlian ini pada anggota dewan komisaris akan mengurangi manajemen laba Perusahaan sementara tidak demikian dengan hasil pengujian pada anggota komite audit

Selfconsistent hybridization expansions for static properties of the Anderson impurity model

By means of a projector-operator formalism we derive an approximation based on a self consistent hybridization expansion to study the ground state properties of the Anderson Impurity model. We applied the approximation to the general case of finite Coulomb repulsion $U$, extending previous work with the same formalism in the infinite-$U$ case. The treatment provides a very accurate calculation of the ground state energy and their related zero temperature properties in the case in which $U$ is large enough, but still finite, as compared with the rest of energy scales involved in the model. The results for the valence of the impurity are compared with exact results that we obtain from equations derived using the Bethe ansatz and with a perturbative approach. The magnetization and magnetic susceptibility is also compared with Bethe ansatz results. In order to do this comparison, we also show how to regularize the Bethe ansatz integral equations necessary to calculate the impurity valence, for arbitrary values of the parameters.Comment: 8 pages, 5 figure

Polarized currents and spatial separation of Kondo state: NRG study of spin-orbital effect in a double QD

A double quantum dot device, connected to two channels that only see each other through interdot Coulomb repulsion, is analyzed using the numerical renormalization group technique. By using a two-impurity Anderson model, and parameter values obtained from experiment [S. Amasha {\it et al.}, Phys. Rev. Lett. {\bf 110}, 046604 (2013)], it is shown that, by applying a moderate magnetic field, and adjusting the gate potential of each quantum dot, opposing spin polarizations are created in each channel. Furthermore, through a well defined change in the gate potentials, the polarizations can be reversed. This polarization effect is clearly associated to a spin-orbital Kondo state having a Kondo peak that originates from spatially separated parts of the device. This fact opens the exciting possibility of experimentally probing the internal structure of an SU(2) Kondo state.Comment: 4+ pages; 4 figures; supplemental material (1 page, 2 figures

Anderson Localization Phenomenon in One-dimensional Elastic Systems

The phenomenon of Anderson localization of waves in elastic systems is studied. We analyze this phenomenon in two different set of systems: disordered linear chains of harmonic oscillators and disordered rods which oscillate with torsional waves. The first set is analyzed numerically whereas the second one is studied both experimentally and theoretically. In particular, we discuss the localization properties of the waves as a function of the frequency. In doing that we have used the inverse participation ratio, which is related to the localization length. We find that the normal modes localize exponentially according to Anderson theory. In the elastic systems, the localization length decreases with frequency. This behavior is in contrast with what happens in analogous quantum mechanical systems, for which the localization length grows with energy. This difference is explained by means of the properties of the re ection coefficient of a single scatterer in each case.Comment: 15 pages, 10 figure

Enhancement of the thermoelectric efficiency in a T-shaped quantum dot system in the linear and nonlinear regimes

In the present work, we investigate the thermoelectric properties of a T-shaped double quantum dot system coupled to two metallic leads incorporating the intra-dot Coulomb interaction. We explore the role of the interference effects and Coulomb blockade on the thermoelectric efficiency of the system in the linear and nonlinear regimes. We studied as well the effect of a Van-Hove singularity of the leads density of states (DOS) at the neighborhood of the Fermi energy, a situation that can be obtained using a carbon nanotube, a graphene nano-ribbon or other contacts with one-dimensional properties. The system is studied above the Kondo temperature. The Coulomb blockade of the electronic charges is studied using the Hubbard III approximation, which properly describes the transport properties of this regime. In the linear response, our results show an enhancement of the thermopower and the figure of merit of the system. For a nonlinear situation, we calculate the thermoelectric efficiency and power output, concluding that the T-shaped double quantum dot is an efficient thermoelectric device. Moreover, we demonstrate the great importance of the DOS Van-Hove singularity at the neighborhood of the Fermi energy to obtain a very significant increase of the thermoelectric efficiency of the system

Kondo and Dicke effect in quantum-dots side coupled to a quantum wire

Electron tunneling through quantum-dots side coupled to a quantum wire, in equilibrium and nonequilibrium Kondo regime, is studied. The mean-field finite-$U$ slave-boson formalism is used to obtain the solution of the problem. We have found that the transmission spectrum shows a structure with two anti-resonances localized at the renormalized energies of the quantum dots. The DOS of the system shows that when the Kondo correlations are dominant there are two Kondo regimes with its own Kondo temperature. The above behavior of the DOS can be explained by quantum interference in the transmission through the two different resonance states of the quantum dots coupled to common leads. This result is analogous to the Dicke effect in optics. We investigate the many body Kondo states as a function of the parameters of the system.Comment: 5 figures. To appear in Phys. Rev.