1,720 research outputs found
Free induction decay of a superposition stored in a quantum dot
We study the free evolution of a superposition initialized with high fidelity
in the neutral-exciton state of a quantum dot. Readout of the state at later
times is achieved by polarized photon detection, averaged over a large number
of cycles. By controlling the fine-structure splitting (FSS) of the dot with a
dc electric field, we show a reduction in the degree of polarization of the
signal when the splitting is minimized. In analogy with the "free induction
decay" observed in nuclear magnetic resonance, we attribute this to hyperfine
interactions with nuclei in the semiconductor. We numerically model this effect
and find good agreement with experimental studies. Our findings have
implications for storage of superpositions in solid-state systems and for
entangled photon pair emission protocols that require a small value of the FSS
Effects of Zeeman spin splitting on the modular symmetry in the quantum Hall effect
Magnetic-field-induced phase transitions in the integer quantum Hall effect
are studied under the formation of paired Landau bands arising from Zeeman spin
splitting. By investigating features of modular symmetry, we showed that
modifications to the particle-hole transformation should be considered under
the coupling between the paired Landau bands. Our study indicates that such a
transformation should be modified either when the Zeeman gap is much smaller
than the cyclotron gap, or when these two gaps are comparable.Comment: 8 pages, 4 figure
Probing the Sensitivity of Electron Wave Interference to Disorder-Induced Scattering in Solid-State Devices
The study of electron motion in semiconductor billiards has elucidated our
understanding of quantum interference and quantum chaos. The central assumption
is that ionized donors generate only minor perturbations to the electron
trajectories, which are determined by scattering from billiard walls. We use
magnetoconductance fluctuations as a probe of the quantum interference and show
that these fluctuations change radically when the scattering landscape is
modified by thermally-induced charge displacement between donor sites. Our
results challenge the accepted understanding of quantum interference effects in
nanostructures.Comment: 8 pages, 5 figures, Submitted to Physical Review
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