99 research outputs found
The Indirect Effects of Trading Restrictions: Evidence from a Quasi-Natural Experiment
Stock market trading restrictions directly affect stock prices and liquidity via constraints on investorsā transactions. They also have indirect effects by altering the information environment. We isolate these indirect effects by analyzing the effect of stock market restrictions on the corporate bond market. Using the staggered relaxation of the restrictions on margin trading and short selling in the Chinese stock market as a quasi-natural experiment, we find that the relaxation of these restrictions on a firmās stock reduces the credit spread of its corporate bond. This effect is more pronounced for firms with more opaque information or lower credit ratings
Background-Free Microwave Signal Generation Based on Unbalanced Temporal Pulse Shaping
We propose a new method to generate background-free high-frequency pulsed microwave signal based on an unbalanced temporal optical pulse shaping (TPS) system and balanced photodetection. The proposed system consists of a polarization modulator and an unbalanced TPS system realized by two conjugate dispersion elements. The carrier frequency of the pulsed microwave signal could be tuned by changing the residual dispersion of the TPS. The proposed method is theoretically analyzed and experimentally demonstrated. The experimental results show that the carrier frequency of the generated microwave pulse could be tuned over a broad frequency range. Moreover, the generated microwave pulse signal is background-free by suppressing the baseband frequency components using balanced photodetection
Kondo Phase in Twisted Bilayer Graphene -- A Unified Theory for Distinct Experiments
A number of interesting physical phenomena have been discovered in
magic-angle twisted bilayer graphene (MATBG), such as superconductivity,
correlated gapped and gapless phases, etc. The gapped phases are believed to be
symmetry-breaking states described by mean-field theories, whereas gapless
phases exhibit features beyond mean field. This work, combining poor man's
scaling, numerical renormalization group, and dynamic mean-field theory,
demonstrates that the gapless phases are the heavy Fermi liquid state with some
symmetries broken and the others preserved. We adopt the recently proposed
topological heavy fermion model for MATBG with effective local orbitals around
AA-stacking regions and Dirac fermions surrounding them. At zero temperature
and most non-integer fillings, the ground states are found to be heavy Fermi
liquids and exhibit Kondo resonance peaks. The Kondo temperature is found
at the order of 1meV. A higher temperature than will drive the system
into a metallic LM phase where disordered LM's and a Fermi liquid coexist. At
integer fillings , is suppressed to zero or a value weaker
than RKKY interaction, leading to Mott insulators or symmetry-breaking states.
This theory offers a unified explanation for several experimental observations,
such as zero-energy peaks and quantum-dot-like behaviors in STM, the
Pomeranchuk effect, and the saw-tooth feature of inverse compressibility, etc.
For future experimental verification, we predict that the Fermi surface in the
gapless phase will shrink upon heating - as a characteristic of the heavy Fermi
liquid. We also conjecture that the heavy Fermi liquid is the parent state of
the observed unconventional superconductivity because the Kondo screening
reduces the overwhelming Coulomb interaction (~60meV) to a rather small
effective interaction (~1meV) comparable to possible weak attractive
interactions.Comment: DMFT calculations for the THF model and discussions on possible
symmetry-breaking states are adde
Expression Characteristics of Hypoxia-Inducible Factor-1Ī± and Its Clinical Values in Diagnosis and Prognosis of Hepatocellular Carcinoma
Compact fiber-optic diode-laser sensor system for wide-dynamicrange relative humidity measurement
Experimental optimization of phase noise performance of optoelectronic oscillator based on directly modulated laser
Evidence for the Intermediate Phase in Bulk (K2O)<sub>x</sub>(GeO2)<sub>1-x</sub> glasses and its consequences on Electrical and Thermal Properties
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