arXiv subjects

S. Siljamäki

Publications and source records attributed to S. Siljamäki.

3 recordsLinked to original sources

arXiv2003

Testing of two-dimensional local approximations in the current-spin and spin-density-functional theories

We study a model quantum dot system in an external magnetic field by using both the spin-density-functional theory and the current-spin-density-functional theory. The theories are used with local approximations for the spin-density and the vorticity. The reliabilities of different parametrizations for the exchange-correlation functionals are tested by comparing the ensuing energetics with quantum Monte Carlo results. The limit where the vorticity dependence should be used in the exchange-correlation functionals is discussed.

cond-mat.mes-hall↗

arXiv2002

Two-electron quantum dot molecule: Composite particles and the spin phase diagram

We study a two-electron quantum dot molecule in a magnetic field by the direct diagonalization of the Hamiltonian matrix. The ground states of the molecule with the total spin S=0 and S=1 provide a possible realization for a qubit of a quantum computer. Switching between the states is best achieved by changing the magnetic field. Based on an analysis of the wave function, we show that the system consists of composite particles formed by an electron and flux quanta attached to it. This picture can also be used to explain the spin phase diagram.

cond-mat.mes-hall↗

arXiv2001

Wigner molecules in quantum dots: a quantum Monte Carlo study

We study two-dimensional quantum dots using the variational quantum Monte Carlo technique in the weak-confinement limit where the system approaches the Wigner molecule, i.e., the classical solution of point charges in an external potential. We observe the spin-polarization of electrons followed by a smooth transition to a Wigner-molecule-like state as the confining potential is made weaker.

cond-mat.mes-hall↗