Related papers: Evaluating charge noise acting on semiconductor qu…
We propose a theoretical model for the low-frequency noise observed in a quantum point contact (QPC) electrostatically defined in the 2D electron gas at a GaAs-AlGaAs interface. In such contacts electron scattering by soft impurity- or…
We present experiments in which self-assembled InAs quantum dots are coupled to a thin, suspended-beam GaAs resonator. The quantum dots are driven resonantly and the resonance fluorescence is detected. The narrow quantum-dot linewidths,…
Double quantum dots are one of the promising two-state quantum systems for realizing qubits. In the quest of successfully manipulating and reading information in qubit systems, it is of prime interest to control the charge response of the…
We study electron transport through a triple quantum dot in ring configuration at finite bias. In particular, we analyze the influence of a gate voltage that detunes one of the dots, such that one branch of the interferometer becomes…
We report the realization of a bonded-bridge on-chip superconducting coil and its use in impedance-matching a highly ohmic quantum dot (QD) to a $\rm{3~GHz}$ measurement setup. The coil, modeled as a lumped-element $LC$ resonator, is more…
We extract the phase coherence of a qubit defined by singlet and triplet electronic states in a gated GaAs triple quantum dot, measuring on timescales much shorter than the decorrelation time of the environmental noise. In this non-ergodic…
Increasing the separation between semiconductor quantum dots offers scaling advantages by fa- cilitating gate routing and the integration of sensors and charge reservoirs. Elongated quantum dots have been utilized for this purpose in GaAs…
With superconducting transmon qubits --- a promising platform for quantum information processing --- two-qubit gates can be performed using AC signals to modulate a tunable transmon's frequency via magnetic flux through its SQUID loop.…
We show that placing a quantum system in contact with an environment can enhance non-Fermi-liquid correlations, rather than destroy quantum effects as is typical. The system consists of two quantum dots in series with two leads; the highly…
A crucial requirement for quantum computing, in particular for scalable quantum computing and error correction, is a fast and high-fidelity qubit readout. For semiconductor based qubits, one limiting factor for local low-power signal…
We identify optimal operating conditions of an entangling two-qubit gate realized by a capacitive coupling of two superconducting charge qubits in a transmission line resonator (the so called "transmons"). We demonstrate that the…
We report an experimentally observed anomalous doubly split spectrum and its split-width fluctuation in an ultrastrongly coupled superconducting qubit and resonator. From an analysis of Rabimodel and circuit model Hamiltonians, we found…
We present a theoretical study of a hybrid circuit-QED system composed of two semiconducting charge-qubits confined in a microwave resonator. The qubits are defined in terms of the charge states of two spatially separated double quantum…
We report a direct measurement of the low-frequency noise spectrum in a superconducting flux qubit. Our method uses the noise sensitivity of a free-induction Ramsey interference experiment, comprising free evolution in the presence of noise…
This letter investigates low frequency 1/ f noise in hBN encapsulated graphene device in a dual gated geometry. The noise study is performed as a function of top gate carrier density (nT G) at different back gate densities (nBG). The noise…
Qubit readout schemes often deviate from ideal projective measurements, introducing critical issues that limit quantum computing performance. In this work, we model charge-sensing-based readout for semiconductor spin qubits in double…
We experimentally demonstrate a tunable hybrid qubit in a five-electron GaAs double quantum dot. The qubit is encoded in the (1,4) charge regime of the double dot and can be manipulated completely electrically. More importantly, dot…
Developing fast, accurate and scalable techniques for quantum state readout is an active area in semiconductor-based quantum computing. Here, we present results on dispersive sensing of silicon corner state quantum dots coupled to…
Semiconductor quantum dots can emit antibunched, single photons on demand with narrow linewidths. However, the observed linewidths are broader than lifetime measurements predict, due to spin and charge noise in the environment. This noise…
Long-distance transfer of quantum information in architectures based on quantum dot spin qubits will be necessary for their scalability. One way of achieving it is to simply move the electron between two quantum registers. Precise control…