5,000 research outputs found
Regional Indexes of Activity: Combining the Old with the New
This paper proposes a framework to construct indexes of activity which links two strands of the index literature – the traditional business cycle analysis and the latent variable approach. To illustrate the method, we apply the framework to Australian regional data, namely to two resource-rich and two service-based states. The results reveal differences in the evolution and drivers of economic activity across the four states. We also demonstrate the value of the Index in a broader context by using a structural vector autoregression (SVAR) approach to analyse the effects of shocks from the US and from China. This Index-SVAR approach facilitates a richer analysis because the unique feature of the index method proposed here allows impulse responses to be traced back to the components.Regional economic activity, coincident indicators, dynamic latent factor model
Fantastic Behavior of High-TC Superconductor Junctions: Tunable Superconductivity
Carrier injection performed in oxygen-deficient YBa2Cu3O7(YBCO)
hetero-structure junctions exhibited tunable resistance that was entirely
different with behaviors of semiconductor devices. Tunable superconductivity in
YBCO junctions, increasing over 20 K in transition temperature, has achieved by
using electric processes. To our knowledge, this is the first observation that
intrinsic property of high TC superconductors superconductivity can be adjusted
as tunable functional parameters of devices. The fantastic phenomenon caused by
carrier injection was discussed based on a proposed charge carrier
self-trapping model and BCS theory.Comment: 5 pages, 4 figure
Quantum Group as Semi-infinite Cohomology
We obtain the quantum group as semi-infinite cohomology of the
Virasoro algebra with values in a tensor product of two braided vertex operator
algebras with complementary central charges . Each braided VOA is
constructed from the free Fock space realization of the Virasoro algebra with
an additional q-deformed harmonic oscillator degree of freedom. The braided VOA
structure arises from the theory of local systems over configuration spaces and
it yields an associative algebra structure on the cohomology. We explicitly
provide the four cohomology classes that serve as the generators of
and verify their relations. We also discuss the possible extensions of our
construction and its connection to the Liouville model and minimal string
theory.Comment: 50 pages, 7 figures, minor revisions, typos corrected, Communications
in Mathematical Physics, in pres
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Giant Pyogenic Granuloma in a Patient with Chronic Lymphocytic Leukemia
Pyogenic granuloma, also known as lobular capillary hemangioma, is a common benign vascular proliferative lesion that can present at any age on the skin or mucous membranes. Most lesions do not exceed 2 cm, but there are a handful of giant cutaneous pyogenic granulomas that have been reported, often in individuals with underlying immune dysfunction. Here, we report the first giant pyogenic granuloma in a patient with a hematological malignancy, chronic lymphocytic leukemia
Heat flux operator, current conservation and the formal Fourier's law
By revisiting previous definitions of the heat current operator, we show that
one can define a heat current operator that satisfies the continuity equation
for a general Hamiltonian in one dimension. This expression is useful for
studying electronic, phononic and photonic energy flow in linear systems and in
hybrid structures. The definition allows us to deduce the necessary conditions
that result in current conservation for general-statistics systems. The
discrete form of the Fourier's Law of heat conduction naturally emerges in the
present definition
Exact dynamics of interacting qubits in a thermal environment: Results beyond the weak coupling limit
We demonstrate an exact mapping of a class of models of two interacting
qubits in thermal reservoirs to two separate spin-bath problems. Based on this
mapping, exact numerical simulations of the qubits dynamics can be performed,
beyond the weak system-bath coupling limit. Given the time evolution of the
system, we study, in a numerically exact way, the dynamics of entanglement
between pair of qubits immersed in boson thermal baths, showing a rich
phenomenology, including an intermediate oscillatory behavior, the entanglement
sudden birth, sudden death, and revival. We find that stationary entanglement
develops between the qubits due to their coupling to a thermal environment,
unlike the isolated qubits case in which the entanglement oscillates. We also
show that the occurrence of entanglement sudden death in this model depends on
the portion of the zero and double excitation states in the subsystem initial
state. In the long-time limit, analytic expressions are presented at weak
system-bath coupling, for a range of relevant qubit parameters
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