Related papers: Measuring pulse heating in Si quantum dots with in…
Electron spins in silicon quantum dots are excellent qubits due to their long coherence times, scalability, and compatibility with advanced semiconductor technology. Although high gate fidelities can be achieved with spin qubits, charge…
Discrete charge fluctuations, routinely observed in semiconductor quantum dot devices, may contribute significantly to device drift and errors resulting from qubit miscalibration. Understanding the nature and origins of these discrete…
Recent advances in scaling up spin-based quantum processors have revealed unanticipated issues related to thermal effects. Microwave pulses required to manipulate and read the qubits are found to overheat the spins environment, which…
Semiconductor qubit devices suffer from the drift of important device parameters as they are operated. The most important example is a shift in qubit operating frequencies. This effect appears to be directly related to the heating of the…
Gate-defined semiconductor quantum dots utilize fast electrical control to manipulate spin and charge states of individual electrons. Electrical pulse distortions can limit control fidelities but are difficult to measure at the device…
Electron spins in silicon have long coherence times and are a promising qubit platform. However, electric field noise in semiconductors poses a challenge for most single- and multi-qubit operations in quantum-dot spin qubits. Here, we…
To achieve quantum computing using semiconductor spin qubits, the spin qubits must be precisely controlled. However, unexpected noise limits this precision and prevents the implementation of error correction codes. Specifically, frequency…
Silicon quantum dot qubits show great promise but suffer from charge noise with a 1/f^\alpha spectrum, where f is frequency and \alpha \lesssim 1. It has recently been proposed that 1/f^\alpha noise spectra can emerge from a few thermally…
Spin qubits have proven to be a feasible candidate for quantum computation, and some realizations of spin qubits already benefit from advanced device manufacturing in the semiconductor industry. Compared to superconducting platforms, spin…
We measure the quantum fluctuations of a pumped nonlinear resonator, using a superconducting artificial atom as an in-situ probe. The qubit excitation spectrum gives access to the frequency and temperature of the intracavity field…
Spin-spin exchange interactions between semiconductor spin qubits allow for fast single and two-qubit gates. During exchange, coupling of the qubits to a surrounding phonon bath may cause errors in the resulting gate. Here, the fidelities…
We report local time-resolved thermometry in a silicon nanowire quantum dot device designed to host a linear array of spin qubits. Using two alternative measurement schemes based on rf reflectometry, we are able to probe either local…
Temporal fluctuations in the superconducting qubit lifetime, $T_1$, bring up additional challenges in building a fault-tolerant quantum computer. While the exact mechanisms remain unclear, $T_1$ fluctuations are generally attributed to the…
We demonstrate a new method to directly manipulate the state of individual two-level systems (TLS) in phase qubits. It allows one to characterize the coherence properties of TLS using standard microwave pulse sequences, while the qubit is…
Spin qubits in quantum dots define an attractive platform for scalable quantum information because of their compatibility with semiconductor manufacturing, their long coherence times, and the ability to operate at temperatures exceeding one…
We theoretically study the relaxation of electron orbital states of a double quantum dot system due to two-phonon processes. In particular, we calculate how the relaxation rates depend on the separation distance between the quantum dots,…
Superconducting microwave resonators are critical to quantum computing and sensing technologies. Additionally, they are common proxies for superconducting qubits when determining the effects of performance-limiting loss mechanisms such as…
We characterize single- and two-qubit operations in a SiGe quantum dot array, from the perspective of its quantum information processing capabilities. The analysis includes rigorous randomized benchmarking of single- and two-qubit gates,…
Solid-state qubit manipulation and read-out fidelities are reaching fault-tolerance, but quantum error correction requires millions of physical qubits and thus a scalable quantum computer architecture. To solve signal-line bandwidth and…
We investigate low-frequency noise in a spin-qubit device made in isotopically purified Si/Si-Ge. Observing sizable cross-correlations among energy fluctuations of different qubits, we conclude that these fluctuations are dominated by…