Quantum state transfer from a single photon to a single electron following selection rule can only occur for a spin-resolved light hole excitation in GaAs quantum dots; However, these phenomena are yet to be experimentally realized. Here, we report on single shot readout of a single electron spin via the Zeeman-resolved light hole excitation using an optical spin blockade method in a GaAs quantum dot and a Pauli spin blockade method in a double GaAs quantum dot. The observed photo-excitation probability strongly depends on the photon polarization, an indication of angular momentum transfer from a single photon to an electron. Our demonstration will open a pathway to further investigation of fundamental quantum physics and applications of quantum networking technology.

Quantum entanglement between different forms of qubits is an indication of the universality of quantum mechanics. Entanglement transfer between light and matter, especially photon and spin, has long been studied as the central concept, but it remains technically challenging for single photons and spins. In this paper, we show paired generation of a single electron in a GaAs quantum dot and a single photon from a single polarization-entangled photon pair. We measure temporal coincidence between the single photo-electron detection and the single photon detection. Considering a single photon polarization is converted to an electron spin via an optical selection rule, the present result indicates the capability of photon to spin entanglement transfer. This may be useful to explore the physics of entanglement transfer and also for applications to quantum teleportation based quantum communication.

We investigate the full counting statistics (FCS) of spin-conserving and spin-flip charge transitions in Paulispin blockade regime of a GaAs double quantum dot. Experimentally, we executed real-time observation of charge transitions and constructed the FCS. A theoretical model is proposed to evaluate all spin-conserving and spin-flip tunnel rates. We enumerate advantages in FCS comparing to waiting time distribution for the evaluation with demonstration of the universal relation between FCS and waiting time distribution We report peculiar statistical features in the FCS, which appear in the system holding spin degeneracy and coexistence of slow and fast transitions. Our experimental results supported by the numerical calculation provide how the spin correlation plays on the full counting statistics. This study is potentially useful for elucidating the spin-related and other complex transition dynamics in classical and quantum systems.

We report on experimental observations of charge-spin cooperative dynamics of two-electron states in a GaAs double quantum dot (QD) located in a non-equilibrium phonon environment. When the phonon energy exceeds the lowest excitation energy in the QD, the spin-flip rate of a single electron strongly enhances. In addition, originated from the spatial gradient of phonon density between the dots, the parallel spin states become more probable than the anti-parallel ones. These results indicate that spin is essential for further demonstrations of single-electron thermodynamic systems driven by phonons, which will greatly contribute to understanding of the fundamental physics of thermoelectric devices.