TY  - JOUR
AU  - Richer, Susanne
AU  - DiVincenzo, David
TI  - Circuit design implementing longitudinal coupling: A scalable scheme for superconducting qubits
JO  - Physical review / B
VL  - 93
IS  - 13
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2016-06667
SP  - 134501
PY  - 2016
AB  - We present a circuit construction for a fixed-frequency superconducting qubit and show how it can be scaled up to a grid with strictly local interactions. The circuit QED realization we propose implements σz type coupling between a superconducting qubit and any number of LC resonators. The resulting longitudinal coupling is inherently different from the usual σx type transverse coupling, which is the one that has been most commonly used for superconducting qubits. In a grid of fixed-frequency qubits and resonators with a particular pattern of always-on interactions, coupling is strictly confined to nearest and next-nearest neighbor resonators; there is never any direct qubit-qubit coupling. We note that just a single unique qubit frequency suffices for the scalability of this scheme. The same is true for the resonators, if the resonator-resonator coupling constants are varied instead. A controlled phase gate between two neighboring qubits can be realized with microwave drives on the qubits, without affecting the other qubits. This fact is a significant advantage for the scalability of this scheme
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000373311300005
DO  - DOI:10.1103/PhysRevB.93.134501
UR  - https://juser.fz-juelich.de/record/824043
ER  -