Dependence of GCRs influx on the Solar North-South Asymmetry

We investigate the dependence of the amount of the observed galactic cosmic ray (GCR) influx on the solar North-South asymmetry using the neutron count rates obtained from four stations and sunspot data in archives spanning six solar cycles from 1953 to 2008. We find that the observed GCR influxes at Moscow, Kiel, Climax and Huancayo stations are more suppressed when the solar activity in the southern hemisphere is dominant compared with when the solar activity in the northern hemisphere is dominant. Its reduction rates at four stations are all larger than those of the suppression due to other factors including the solar polarity effect on the GCR influx. We perform the student's t-test to see how significant these suppressions are. It is found that suppressions due to the solar North-South asymmetry as well as the solar polarity are significant and yet the suppressions associated with the former are larger and more significant.Comment: 17 pages, 3figures, accepted to JAST

Photon-Assisted Quasiparticle Transport and Andreev Transport through an Interacting Quantum Dot

Resonant tunneling through a quantum dot coupled to superconducting reservoirs in the presence of time-dependent external voltage has been studied. A general formula of the current is derived based on the nonequilibrium Green's function technique. Using this formula photon-assisted quasiparticle transport has been investigated for the quantum dot connected to superconductors. In addition, resonant Andreev transport through a strongly correlated quantum dot connected to a normal metallic lead and a superconducting lead is studied.Comment: 9 pages(1 column) with 3 figure

Anomaly Manifestation of Lieb-Schultz-Mattis Theorem and Topological Phases

The Lieb-Schultz-Mattis (LSM) theorem dictates that emergent low-energy states from a lattice model cannot be a trivial symmetric insulator if the filling per unit cell is not integral and if the lattice translation symmetry and particle number conservation are strictly imposed. In this paper, we compare the one-dimensional gapless states enforced by the LSM theorem and the boundaries of one-higher dimensional strong symmetry-protected topological (SPT) phases from the perspective of quantum anomalies. We first note that, they can be both described by the same low-energy effective field theory with the same effective symmetry realizations on low-energy modes, wherein non-on-site lattice translation symmetry is encoded as if it is a local symmetry. In spite of the identical form of the low-energy effective field theories, we show that the quantum anomalies of the theories play different roles in the two systems. In particular, We find that the chiral anomaly is equivalent to the LSM theorem, whereas there is another anomaly, which is not related to the LSM theorem but is intrinsic to the SPT states. As an application, we extend the conventional LSM theorem to multiple-charge multiple-species problems and construct several exotic symmetric insulators. We also find that the (3+1)d chiral anomaly provides only the perturbative stability of the gapless-ness local in the parameter space.Comment: 14 + 3 pages, 1 figure. (The first two authors contributed equally to the work.

Nonlinearity Identification and Flow Control for Low-Reynolds Number Aerodynamics with Unsteady Free-Stream

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97137/1/AIAA2012-76.pd

The Acquisitions of Information Technology Firms by M&A Intents: An Empirical Analysis

Over the last decades, a large number of firms have undertaken mergers and acquisitions (M&As) to create synergies through increased production efficiency, increased market power, and quality improvements. Moreover, we have also recently witnessed that an increasing number of firms acquire information technology (IT) firms to create synergies from the customer side as well as the production side. In this study, we examine the post-merger risk of the acquiring firm, measured as its return volatility when IT firms are acquired, and seek to understand the dynamics surrounding M&A transactions. We also identify the conditions under which acquiring firms can mitigate the risks resulting from M&A transactions. We find that a strong run-up in risk occurs before M&A transactions are initiated, but this risk begins to decline over the post-merger years. However, we expect that post-merger risks tend to persist when firms seek M&A transactions with a customer-side motive, whereas this does not occur with a production-side motive. Moreover, we expect to find the conditions under which a firm can mitigate risk from the acquisition of IT firms contingent on its M&A motives

Value Discount of Business Groups Surrounding the Asia Financial Crisis: Evidence from Korean Chaebols

Asian Financial Crisis, Business Group, Chaebol, Diversification, Firm Value

Modeling of Dielectric Barrier Discharge Plasma Actuator

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76232/1/AIAA-2007-4531-402.pd