Nanowerk November 26, 2024 Quantum devices such as spin qubits have been extensively investigated in electrostatically confined quantum dots using high-quality semiconductor heterostructures like GaAs and Si. Researchers in Japan demonstrated electrostatically forming the quantum dots in ZnO heterostructures. They uncovered the distinctive signature of the Kondo effect independent of the even-odd electron number parity, which contrasts with the typical behavior of the Kondo effect in GaAs. By analyzing temperature and magnetic field dependences, they found that the absence of the even-odd parity in the Kondo effect was not straightforwardly interpreted by the considerations developed for conventional semiconductors. Based on […]
Tag Archives: Spin qubits
A three-qubit entangled state has been realized in a fully controllable array of spin qubits in silicon
Phys.org September 10, 2021 Researchers in Japan have developed a device consisting of a triple quantum dot on a silicon/silicon–germanium heterostructure and controlled through aluminum gates. Each quantum dot can host one electron, whose spin-up and spin-down states encode a qubit. An on-chip magnet generates a magnetic-field gradient that separates the resonance frequencies of the three qubits, so that they can be individually addressed. They first entangled two of the qubits by implementing a two-qubit gate and then realized three-qubit entanglement by combining the third qubit and the gate. The resulting three-qubit state had a remarkably high state fidelity of […]
Physicists break distance record for electron spin-state transmission in spin qubits
Physics World October 10, 2019 A team of researchers in the US (University of Rochester, Purdue University) has demonstrated coherent spin-state transfer along an array of four electrons confined in a quadruple quantum dot in a GaAs/AlGaAs heterostructure. When they applied a voltage pulse to a gate between two quantum dots, the electrons in the dots exchanged their spin states via Heisenberg exchange coupling. By applying a series of voltage pulses to specific gates, the researchers were able to shuttle the spin states of the electrons back and forth. They were able to transmit the spins of entangled electrons using […]