Related papers: Enhanced spin coherence at the sweet spot of a sel…
The loss of information about the relative phase between two quantum states, known as decoherence, strongly limits resolution in electron paramagnetic spectroscopy and hampers the use of molecules for quantum information processing. At low…
In quantum dots made from materials with nonzero nuclear spins, hyperfine coupling creates a fluctuating effective Zeeman field (Overhauser field) felt by electrons, which can be a dominant source of spin qubit decoherence. We characterize…
We predict a spin pure dephasing channel in electron relaxation between states with unequal Zeeman splittings, exemplified by a spin-preserving electron tunneling between quantum dots in a magnetic field. The dephasing is caused by a…
We investigate decoherence due to pure dephasing of a localized spin qubit interacting with a nuclear spin bath. Although in the limit of a very large magnetic field the only decoherence mechanism is spectral diffusion due to dipolar…
We estimate the spin relaxation rate due to spin-orbit coupling and acoustic phonon scattering in weakly-confined quantum dots with up to five interacting electrons. The Full Configuration Interaction approach is used to account for the…
We propose a scheme based on using the singlet ground state of an electron spin pair in a double quantum dot nanostructure as a suitable set-up for detecting entanglement between electron spins via the measurement of an optimal entanglement…
Optimal working points or "sweet spots" have arisen as an important tool for mitigating charge noise in quantum dot logical spin qubits. The exchange-only qubit provides an ideal system for studying this effect because $Z$ rotations are…
We investigate hyperfine induced electron spin and entanglement dynamics in a system of two quantum dot spin qubits. We focus on the situation of zero external magnetic field and concentrate on approximation-free theoretical methods. We…
Solid-state spin defects, especially nuclear spins with potentially achievable long coherence times, are compelling candidates for quantum memories and sensors. However, their current performances are still limited by the decoherence due to…
States with long coherence are a crucial requirement for qubits and quantum memories. Nuclear spins in epitaxial quantum dots are a great candidate, offering excellent isolation from external environments and on-demand coupling to optical…
We consider a single electron in a 1D quantum dot with a static slanting Zeeman field. By combining the spin and orbital degrees of freedom of the electron, an effective quantum two-level (qubit) system is defined. This pseudo-spin can be…
Understanding and control of the spin relaxation time $T_1$ is among the key challenges for spin based qubits. A larger $T_1$ is generally favored, setting the fundamental upper limit to the qubit coherence and spin readout fidelity. In…
The energy landscape of a single electron in a triple quantum dot can be tuned such that the energy separation between ground and excited states becomes a flat function of the relevant gate voltages. These so-called sweet spots are…
Understanding and protecting the coherence of individual quantum systems is a central challenge in quantum science and technology. Over the last decades, a rich variety of methods to extend coherence have been developed. A complementary…
The performance of solid-state quantum sensors based on electronic spin defects is often limited by the presence of environmental spin impurities that cause decoherence. A promising approach to improve these quantum sensors is to convert…
The exchange interaction in a singlet-triplet qubit defined by two-electron states in the double-quantum-dot system ("two-electron singlet-triplet qubit") typically varies monotonically with the exchange interaction and thus carries no…
Rabi nutations of a single electron spin in a single defect center have been detected. The coherent evolution of the spin quantum state is followed via optical detection of the spin state. Coherence times up to several microseconds at room…
The control of discrete quantum states in solids and their use for quantum information processing is complicated by the lack of a detailed understanding of the mechanisms responsible for qubit decoherences. For spin qubits in semiconductor…
Semiconductor quantum dots with confined electron or hole spins show promise for quantum information processing as they allow for efficient electric field-driven qubit manipulation. However, their susceptibility to electric noise poses a…
Electron spin qubit coherence in quantum dots is ultimately limited by random nuclear spin bath fluctuations. Here we aim to eliminate this randomness by making spin bath evolution deterministic. We introduce spin bath control sequences,…