Dephasing of charge and spin in semiconductor quantum dots
نویسندگان
چکیده
Phonon induced unavoidable decoherence of orbital degrees of freedom (charge) in quantum dots is studied and the relevant time scales are estimated for state-of-the-art self-assembled nanostructures. An significant enhancement of the effective Fröhlich constant due to localization is indicated. Temporal partial inefficiency of spin Pauli blocking in quantum dots, caused by lattice inertia, is predicted. For quantum dots placed in a diluted magnetic semiconductor medium a magnon-induced dephasing of spin localized in quantum dot is also estimated. The assessed decoherence rates for both orbital and spin degrees of freedom in semiconductor nanostructures turn out to not satisfy DiVincenzo conditions required for quantum error correction scheme implementations.
منابع مشابه
Control and measurement of electron spins in semiconductor quantum dots
We present an overview of experimental steps taken towards using the spin of a single electron trapped in a semiconductor quantum dot as a spin qubit [Loss and DiVincenzo, Phys. Rev. A 57, 120 (1998)]. Fabrication and characterization of a double quantum dot containing two coupled spins has been achieved, as well as initialization and single-shot read-out of the spin state. The relaxation time ...
متن کاملHigh resolution coherent population trapping on a single hole spin in a semiconductor quantum dot.
We report high resolution coherent population trapping on a single hole spin in a semiconductor quantum dot. The absorption dip signifying the formation of a dark state exhibits an atomic physicslike dip width of just 10 MHz. We observe fluctuations in the absolute frequency of the absorption dip, evidence of very slow spin dephasing. We identify the cause of this process as charge noise by, fi...
متن کاملDephasing of excitons and multiexcitons in undoped and p-doped InAs/GaAs quantum dots-in-a-well
We report an experimental investigation of the dephasing of excitons and multiexcitons in technologically relevant undoped and p-doped InAs/GaAs dot-in-a-well structures emitting near 1.3 m wavelength. Using a transient four-wave mixing technique in heterodyne detection, we measured the excitonic dephasing due to phonon coupling in the temperature range from 5 to 300 K, and the multiexcitonic d...
متن کاملSuppressing spin qubit dephasing by nuclear state preparation.
Coherent spin states in semiconductor quantum dots offer promise as electrically controllable quantum bits (qubits) with scalable fabrication. For few-electron quantum dots made from gallium arsenide (GaAs), fluctuating nuclear spins in the host lattice are the dominant source of spin decoherence. We report a method of preparing the nuclear spin environment that suppresses the relevant componen...
متن کاملSpins in few-electron quantum dots
The canonical example of a quantum-mechanical two-level system is spin. The simplest picture of spin is a magnetic moment pointing up or down. The full quantum properties of spin become apparent in phenomena such as superpositions of spin states, entanglement among spins, and quantum measurements. Many of these phenomena have been observed in experiments performed on ensembles of particles with...
متن کامل