# Dresden 2017 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

# MA: Fachverband Magnetismus

## MA 18: Transport: Quantum Coherence and Quantum Information Systems - Theory (jointly with MA, HL)

### MA 18.7: Vortrag

### Dienstag, 21. März 2017, 11:00–11:15, HSZ 103

**Proximity Effect in Normal-Metal Quasiparticle Traps** — •Amin Hosseinkhani^{1,2} and Ginaluigi Catelani^{1} — ^{1}Peter Grunberg Institut (PGI-2), Forschungszentrum Jülich, Jülich, Germany — ^{2}JARA-Institute for Quantum Information, RWTH Aachen University, Aachen, Germany

In many superconducting devices, including qubits, quasiparticle excitations are detrimental. A normal metal (N) in contact with a superconductor (S) can trap these excitations. However, the contact between N and S modifies the properties of both materials, a phenomenon known as proximity effect which has drawn attention since the '60s. Despite this long history, we find new analytical results for the density of states, which shows a square root threshold behavior at the minigap energy. In superconducting qubits, the trap must be placed far enough from a Josephson junction in order not to harm the qubit coherence. To estimate the minimum trap-junction separation, we study how the density of states in the superconductor depends on the distance from the trap. For high interface resistance between N and S, a separation of several (5-7) coherence lengths is sufficient.