9,285 research outputs found
Topological quantum phase transition in an extended Kitaev spin model
We study the quantum phase transition between Abelian and non-Abelian phases
in an extended Kitaev spin model on the honeycomb lattice, where the periodic
boundary condition is applied by placing the lattice on a torus. Our analytical
results show that this spin model exhibits a continuous quantum phase
transition. Also, we reveal the relationship between bipartite entanglement and
the ground-state energy. Our approach directly shows that both the entanglement
and the ground-state energy can be used to characterize the topological quantum
phase transition in the extended Kitaev spin model.Comment: 9 Pages, 4 figure
Implementing topological quantum manipulation with superconducting circuits
A two-component fermion model with conventional two-body interactions was
recently shown to have anyonic excitations. We here propose a scheme to
physically implement this model by transforming each chain of two two-component
fermions to the two capacitively coupled chains of superconducting devices. In
particular, we elaborate how to achieve the wanted operations to create and
manipulate the topological quantum states, providing an experimentally feasible
scenario to access the topological memory and to build the anyonic
interferometry.Comment: 4 pages with 3 figures; V2: published version with minor updation
Dark Periods in Rabi Oscillations of Superconducting Phase Qubit Coupled to a Microscopic Two-Level System
We proposed a scheme to demonstrate macroscopic quantum jumps in a
superconducting phase qubit coupled to a microscopic two-level system in the
Josephson tunnel junction. Irradiated with suitable microwaves, the Rabi
oscillations of the qubit exhibit signatures of quantum jumps: a random
telegraph signal with long intervals of intense macroscopic quantum tunneling
events (bright periods) interrupted by the complete absence of tunneling events
(dark periods). An analytical model was developed to describe the width of the
dark periods quantitatively. The numerical simulations indicate that our
analytical model captured underlying physics of the system. Besides calibrating
the quality of the microscopic two-level system, our results have significance
in quantum information process since dark periods in Rabi oscillations are also
responsible for errors in quantum computing with superconducting qubits.Comment: 9 pages, 8 figure
Connective tissue growth factor (CTGF, CCN2) gene regulation: a potent clinical bio-marker of fibroproliferative disease?
The CCN (cyr61, ctgf, nov) family of modular proteins regulate diverse biological affects including cell adhesion, matrix production, tissue remodelling, proliferation and differentiation. Recent targeted gene disruption studies have demonstrated the CCN family to be developmentally essential for chondrogenesis, osteogenesis and angiogenesis. CCN2 is induced by agents such as angiotensin II, endothelin-1, glucocorticoids, HGF, TGFΞ², and VEGF, and by hypoxia and biomechanical and shear stress. Dysregulated expression of CCN2 has also been widely documented in many fibroproliferative diseases. This mini-review will focus on CCN2, and the recent progress in understanding CCN2 gene regulation in health and disease. That CCN2 should be considered a novel and informative surrogate clinical bio-marker for fibroproliferative disease is discussed
Quantum criticality of the Lipkin-Meshkov-Glick Model in terms of fidelity susceptibility
We study the critical properties of the Lipkin-Meshkov-Glick Model in terms
of the fidelity susceptibility. By using the Holstein-Primakoff transformation,
we obtain explicitly the critical exponent of the fidelity susceptibility
around the second-order quantum phase transition point. Our results provide a
rare analytical case for the fidelity susceptibility in describing the
universality class in quantum critical behavior. The different critical
exponents in two phases are non-trivial results, indicating the fidelity
susceptibility is not always extensive.Comment: 3 figure
ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(FeRu)As
We used high-energy resolution angle-resolved photoemission spectroscopy to
extract the momentum dependence of the superconducting gap of Ru-substituted
Ba(FeRu)As ( K). Despite a strong
out-of-plane warping of the Fermi surface, the magnitude of the superconducting
gap observed experimentally is nearly isotropic and independent of the
out-of-plane momentum. More precisely, we respectively observed 5.7 meV and 4.5
meV superconducting gaps on the inner and outer -centered hole Fermi
surface pockets, whereas a 4.8 meV gap is recorded on the M-centered electron
Fermi surface pockets. Our results are consistent with the model with
a dominant antiferromagnetic exchange interaction between the next-nearest Fe
neighbors.Comment: 5 pages, 4 figure
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