183 research outputs found
Effective theory for universal seesaw model and FCNC
We study the quark sector of the universal seesaw model with SU(2)
SU(2) .The model incorporates the seesaw mechanism
with the vector-like quarks (VLQs). The purpose of this work is to study the
model with the effective theory. After integrating the heavy five VLQs, we
derive the effective theory with four up-type quark and three down type quark.
In this work, the FCNC of Z boson for top quark and top quark is
derived.Comment: 4 pages, Contribution to the proceedings for International Conference
on Kaon Physics 202
Gate-electric-field and magnetic-field control of versatile topological phases in a semi-magnetic topological insulator
Surface states of a topological insulator demonstrate interesting quantum
phenomena, such as the quantum anomalous Hall (QAH) effect and the quantum
magnetoelectric effect. Fermi energy tuning plays a role in inducing phase
transitions and developing future device functions. Here, we report on
controlling the topological phases in a dual-gate field-effect transistor of a
semi-magnetic topological insulator heterostructure. The heterostructure
consists of magnetized one-surface and non-magnetic other-surface. By tuning
the Fermi energy to the energy gap of the magnetized surface, the Hall
conductivity becomes close to the half-integer quantized Hall
conductivity , exemplifying parity anomaly. The dual-gate control
enables the band structure alignment to the two quantum Hall states with
and 0 under a strong magnetic field. These states are
topologically equivalent to the QAH and axion insulator states, respectively.
Precise and independent control of the band alignment of the top and bottom
surfaces successively induces various topological phase transitions among the
QAH, axion insulator, and parity anomaly states in magnetic topological
insulators.Comment: 20 pages, 4 figure
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