Coupling spin qubits via superconductors

TY - JOUR

T1 - Coupling spin qubits via superconductors

AU - Leijnse, Martin

AU - Flensberg, Karsten

PY - 2013/8/6

Y1 - 2013/8/6

N2 - We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length.

AB - We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length.

U2 - 10.1103/PhysRevLett.111.060501

DO - 10.1103/PhysRevLett.111.060501

M3 - Journal article

C2 - 23971543

SN - 0031-9007

VL - 111

SP - 060501

JO - Physical Review Letters

JF - Physical Review Letters

IS - 6

ER -