Related papers: Second Order Perturbation Theory for a Superconduc…
The current status of the recent developments of the second-order gauge-invariant cosmological perturbation theory is reviewed. To show the essence of this perturbation theory, we concentrate only on the universe filled with a single scalar…
Quantum dots are nanostructures made of semiconducting materials that are engineered to hold a small amount of electric charge (a few electrons) that is controlled by external gate and may hence be considered as tunable artificial atoms. A…
We investigate sequential tunneling transport through a semiconductor double quantum dot structure by combining a simple microscopic quantum confinement model with a Mott-Hubbard type correlation model. We calculate nonperturbatively the…
An analogue of Kolmogorov's superconvergent perturbation theory in classical mechanics is constructed for self adjoint operators. It is different from the usual Rayleigh--Schr\"odinger perturbation theory and yields expansions for…
The Stark effect in hydrogen and the cubic anharmonic oscillator furnish examples of quantum systems where the perturbation results in a certain ionization probability by tunneling processes. Accordingly, the perturbed ground-state energy…
The conductance through a serial double dot structure for which the inter-dot tunneling is stronger than the tunneling to the leads is studied using the numerical density matrix renormalization group method and analytic arguments. When the…
We show that the perturbative expansion of the two-level correlation function, $R(\omega)$, in disordered conductors can be understood semiclassically in terms of self-intersecting particle trajectories. This requires the extension of the…
We review the quantum interference effects in a system of interacting electrons confined to a quantum dot. The review starts with a description of an isolated quantum dot. We discuss the status of the Random Matrix theory (RMT) of the…
Spin-polarized transport through a double quantum dot system attached to a common superconducting lead and two ferromagnetic electrodes (fork geometry) is investigated theoretically. The key objective of the analysis is to describe the…
Motivated by activities of several experimental groups we investigate electron transport through two coherent, strongly coupled quantum dots ("double quantum dots"), taking into account both intra- and inter-dot Coulomb interactions. The…
In this paper we present a new formulation of the change of gauge formulas in second order cosmological perturbation theory which unifies and simplifies known results. Our approach is based on defining new second order scalar perturbation…
We report on a novel Kondo phenomenon of interacting quantum dots coupled asymmetrically to a normal and a superconducting lead. The effects of intradot Coulomb interaction and Andreev tunneling give rise to Andreev bound resonances. As a…
A general theoretical formulation for the effect of a strong on-site Coulomb interaction on the time-dependent electron transport through a quantum dot under the influence of arbitrary time-varying bias voltages and/or external fields is…
High order perturbation theory has seen an unexpected recent revival for controlled calculations of quantum many-body systems, even at strong coupling. We adapt integration methods using low-discrepancy sequences to this problem. They…
Coulomb blockaded transport of topological superconducting nanowires provides an opportunity to probe the localization of states at both ends of the system in a two-terminal geometry. In addition, it provides a way for checking for subgap…
We discuss the effect of quantum interference on transport through a quantum dot system. We introduce an indirect coherent coupling parameter alpha, which provides constructive/destructive interference in the transport current depending on…
The formation of electron pairs is a prerequisite of superconductivity. The fermionic nature of electrons yields four classes of superconducting correlations with definite symmetry in spin, space and time. Here, we suggest double quantum…
Using the closed-time-path formalism, we construct perturbative frameworks, in terms of quasiparticle picture, for studying quasiuniform relativistic quantum field systems near equilibrium and non-equilibrium quasistationary systems. We…
We have constructed a perturbation theory to treat interactions that can include the Coulomb interaction, describing a physical problem that is often encountered in nuclear physics. The Coulomb part is not treated perturbatively; the exact…
Perturbation theory (PT) might be one of the most powerful and fruitful tools for both physicists and chemists, which evoked an explosion of applications with the blooming of atomic and subatomic physics. Even though PT is well-used today,…