Nuclear spin relaxation and spin squeezing under electric quadrupole interaction
Author
Aksu, Yağmur
Advisor
Bulutay, Ceyhun
Date
2015-08Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Nuclear spins dynamics recently gained prominence for semiconductor quantum
information technologies. At least two rami cations can be mentioned within
this context: rst, as a decoherence channel for carrier spin qubit stored in a
quantum dot, and second as a potential quantum memory with the proviso that
the nuclear spin bath can be tamed. To shed light on either of these matters,
this thesis presents numerical simulations of spin dynamics of quadrupolar nuclei
which constitute a large fraction of group III-V semiconductors. Particular
attention is devoted to the electric quadrupole interaction that prevail in these
strained semiconductor structures. Within Lindblad master equation formalism,
the saturation under an incoherent radio frequency pump, and subsequent relaxation
of spin-3/2 nuclei are studied. The quadrupole interaction does not manifest
itself via a conspicuous ngerprint in these processes other than causing faster
relaxation. However, we identify that its prime role is in spin squeezing. The
characteristics of all spins between 1/2 to 9/2 have been thoroughly investigated
under one-axis, mixed-axis, and two-axis countertwisting conditions. Our main
conclusion is that the presence of quadrupole interaction substantially degrades
the average level of squeezing, which further complicates the quantum control of
nuclear spin bath
uctuations.