Related papers: Magnetic-Field-Induced Transition in a Quantum Dot…
We perform a Hartree-Fock calculation in order to describe the ground state of a vertical double quantum dot in the absence of magnetic fields parallel to the growth direction. Intra- and interdot exchange interactions determine the singlet…
We derive the Ginzburg-Landau-Wilson theory for the superconducting phase transition in two dimensions and in the magnetic field. Without disorder the theory describes a fluctuation induced first-order quantum phase transition into the…
A quantum phase transition is a dramatic event marked by large spatial and temporal fluctuations, where one phase of matter with its ground state and tower of excitations reorganizes into a completely different phase. We provide new insight…
In these lectures, superconductivity in impure thin films close to the absolute zero of temperature is discussed. The behavior as function of the applied magnetic field and the amount of impurities suggests the presence of a…
We study the quantum operation of coupled superconducting flux qubits under a microwave irradiation. The flux qubits can be described as magnetic dipole moments in the limit of weak microwave field amplitude consistent with usual…
We demonstrate electron redistribution caused by magnetic field on a single quantum dot measured by means of a quantum point contact as non-invasive detector. Our device which is fabricated by local anodic oxidation allows to control…
When subjected to pressure, the prototypical heavy-fermion antiferromagnet CeRhIn5 becomes superconducting, forming a broad dome of superconductivity centered around 2.35 GPa (=P2) with maximal Tc of 2.3 K. Above the superconducting dome,…
We predict a huge interference effect contributing to the conductance through large ultra-clean quantum dots of chaotic shape. When a double-dot structure is made such that the dots are the mirror-image of each other, constructive…
For a system at a temperature of absolute zero, all thermal fluctuations are frozen out, while quantum fluctuations prevail. These microscopic quantum fluctuations can induce a macroscopic phase transition in the ground state of a many-body…
Quantum phase transitions are an established setting for emergent phenomena driven by strong electronic correlations, including strange metals and unconventional superconductivity. These have been explored extensively in Kondo lattice…
Interplay between the Mott transition and the multicritical phenomenon of d-wave superconductivity (SC) and antiferromagnetism (AF) is studied theoretically. We describe the Mott transition, which is analogous to a liquid-gas phase…
The recent experimental demonstration of spin-polarized supercurrents offer a venue for establishment of a superconducting analogue to conventional spintronics. Whereas domain wall motion in purely magnetic structures is a well-studied…
We theoretically investigate electronic transport through a junction where a quantum dot (QD) is tunnel coupled on both sides to semiconductor nanowires with strong spin-orbit interaction and proximity-induced superconductivity. The results…
The insertion of a magnetic impurity in a superconductor induces a first order quantum phase transition as the coupling to the electronic spin density increases. As the transition is crossed, a discontinuity is exhibited by various…
We study macroscopic quantum tunneling of the magnetic moment in a single-domain particle placed above the surface of a superconductor. Such a setup allows one to manipulate the height of the energy barrier, preserving the degeneracy of the…
We discuss the dynamics of magnetic moments in d-wave superconductors, in particular we focus on moments induced by doping non-magnetic impurities into cuprates. The interaction of such moments with the Bogoliubov quasiparticles of the…
We consider electron transport along a single-mode channel which is in contact, via tunnel junctions in its walls, with two quantum dots. Electron tunneling to and from the dots contributes to the electron backscattering, and thus modifies…
The consequences of localized, classical magnetic moments in superconductors are explored and their effect on the spectral properties of the intragap bound states is studied. Above a critical moment, a localized quasiparticle excitation in…
We investigate the magnetic field evolution of the superconducting state in a strongly disordered NbN thin film which exhibits a magnetic field tuned superconductor to insulator-like transition, employing low temperature scanning tunneling…
Novel effects emerge from an interplay between multiple Andreev reflections and Coulomb interaction in quantum dot coupled to superconducting leads and subject to a finite potential bias $V$. Combining an intuitive physical picture with…