Phys.org December 28, 2018
Single-spin qubits in semiconductor quantum dots hold promise for universal quantum computation. However, initialization and readout of a qubit is orders of magnitude slower than control. An international team of researchers (Japan, France, Germany, Switzerland) combined slow initializing single-spin qubit called a Loss-DiVincenzo qubit, which has very high control fidelity and a singlet-triplet qubit, which has quick initialization and read out, but quickly becomes decoherent. For the study they combined the two types with a type of quantum gate known as a controlled phase gate, which allowed spin states to be entangled between the qubits in a time fast enough to maintain the coherence, allowing the state of the single-spin qubit to be read out by the fast singlet-triplet qubit measurement. The research demonstrates that different types of quantum dots can be combined on a single device to overcome their respective limitations… read more. Open Access TECHNICAL ARTICLEÂ
Hybrid qubits solve key hurdle to quantum computing Schematic of the device. Credit: RIKEN