Enhanced spin-polarization lifetimes

Enhanced spin-polarization lifetimes in a two-dimensional electron gas in a gate-controlled GaAs quantum well Exciton, trion, and electron spin dynamics in a 20-nm-wide modulation-doped GaAs single quantum well are investigated using resonant ultrafast two-color Kerr rotation spectroscopy. Excitons and trions are selectively detected by resonant probe pulses while their relative spectral weight is controlled by […]

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Quantum state tomography

Quantum state tomography of large nuclear spins in a semiconductor quantum well: Optimal robustness against errors as quantified by condition numbers We discuss methods of quantum state tomography for solid-state systems with a large nuclear spin I=3/2 in nanometer-scale semiconductors devices based on a quantum well. Due to quadrupolar interactions, the Zeeman levels of these […]


Quantum energy teleportation without a limit of distance

Quantum energy teleportation (QET) is, from the operational viewpoint of distant protocol users, energy transportation via local operations and classical communication. QET has various links to fundamental research fields including black-hole physics, the quantum theory of Maxwell’s demon, and quantum entanglement in condensed-matter physics. However, the energy that has been extracted using a previous QET […]


Real-space imaging of fractional quantum Hall liquids

Electrons in semiconductors usually behave like a gas―independent particles. However, when confined to two dimensions under a perpendicular magnetic field at low temperatures, they condense into an incompressible quantum liquid. This phenomenon, known as the fractional quantum Hall (FQH) effect1, is a quantum mechanical manifestation of the macroscopic behaviour of correlated electrons that arises when […]