A controlled quantum system can alter its environment by feedback, leading to reduced-entropy states of the environment and to improved system coherence. Here, using a quantum-dot electron spin as a control and probe, we prepare the quantum-dot nuclei under the feedback of coherent population trapping and observe their evolution from a thermal to a reduced-entropy state, with the immediate cons...

A room temperature nuclear magnetic resonance force microscope (MRFM), fitted in a 1Tesla electromagnet, is used to measure the nuclear spin relaxation of H in a micron-size (70ng) crystal of ammonium sulfate. NMR sequences, combining both pulsed and continuous wave r.f. fields, have allowed us to measure mechanically T2 and T1, the transverse and longitudinal spin relaxation times. Because two...

Qubits, the quantum mechanical bits required for quantum computing, must retain their quantum states for times long enough to allow the information contained in them to be processed. In many types of electron-spin qubits, the primary source of information loss is decoherence due to the interaction with nuclear spins of the host lattice. For electrons in gate-defined GaAs quantum dots, spin-echo...

A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins pla...

We analyze the ordered state of nuclear spins embedded in an interacting two-dimensional electron gas (2DEG) with Rashba spin-orbit interaction (SOI). Stability of the ferromagnetic nuclear-spin phase is governed by nonanalytic dependences of the electron spin susceptibility χ on the momentum (q̃) and on the SOI coupling constant (α). The uniform (q̃ = 0) spin susceptibility is anisotropic (with ...

We present a comprehensive theory of nuclear spin polarization of He and Xe gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are ~1! spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; ~2! spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; ~3!...

Abstract The detection of nuclear spins using individual electron has enabled diverse opportunities in quantum sensing and information processing. Proof-of-principle experiments have demonstrated atomic-scale imaging nuclear-spin samples controlled multi-qubit registers. However, to image more complex realize larger-scale processors, computerized methods that efficiently automatically character...

Nuclear level densities (NLDs) are key ingredients in calculations of neutron capture rates for rich isotopes nuclear astrophysics applications. Available experimental NLDs limited mainly to nuclei near stability. Therefore, theoretical models employed predict the nuclei. Here we present a methodology calculating spin- and parity- dependent using methods statistical spectroscopy, based on Shell...