29,270 research outputs found
Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals
The roles of critical valence fluctuations of Ce and Yb are discussed as a
key origin of several anomalies observed in Ce- and Yb-based heavy fermion
systems. Recent development of the theory has revealed that a magnetic field is
an efficient control parameter to induce the critical end point of the
first-order valence transition. Metamagnetism and non-Fermi liquid behavior
caused by this mechanism are discussed by comparing favorably with CeIrIn5,
YbAgCu4, and YbIr2Zn20. The interplay of the magnetic order and valence
fluctuations offers a key concept for understanding Ce- and Yb-based systems.
It is shown that suppression of the magnetic order by enhanced valence
fluctuations gives rise to the coincidence of the magnetic-transition point and
valence-crossover point at absolute zero as a function of pressure or magnetic
field. The interplay is shown to resolve the outstanding puzzle in CeRhIn5 in a
unified way. The broader applicability of this newly clarified mechanism is
discussed by surveying promising materials such as YbAuCu4, beta-YbAlB4, and
YbRh2Si2.Comment: 17 pages, 8 figures, invited paper in special issue on strongly
correlated electron system
Quantum multiparty key distribution protocol without use of entanglement
We propose a quantum key distribution (QKD) protocol that enables three
parties agree at once on a shared common random bit string in presence of an
eavesdropper without use of entanglement. We prove its unconditional security
and analyze the key rate.Comment: 8 pages, no figur
Raman spectroscopy on mechanically exfoliated pristine graphene ribbons
We present Raman spectroscopy measurements of non-etched graphene
nanoribbons, with widths ranging from 15 to 160 nm, where the D-line intensity
is strongly dependent on the polarization direction of the incident light. The
extracted edge disorder correlation length is approximately one order of
magnitude larger than on previously reported graphene ribbons fabricated by
reactive ion etching techniques. This suggests a more regular crystallographic
orientation of the non-etched graphene ribbons here presented. We further
report on the ribbons width dependence of the line-width and frequency of the
long-wavelength optical phonon mode (G-line) and the 2D-line of the studied
graphene ribbons
National Innovation Ecosystems: The Similarity and Disparity of Japan-US Technology Policy Systems toward a Service- Oriented Economy
Coinciding with the announcement of the National Innovation Ecosystem proposed by the US Council on Competitiveness, Japan's Industrial Structure Council proposed a significant shift from a technology policy to an innovation policy based on the ecosystem concept.
Aiming at analyzing the complex mutual relations between human activities centered around industry and the surrounding environment, Japan's Ministry of International Trade and Industry postulated the concept of industrial ecology in the early 1970s, similar to that initiated in the USA in the early 1990s by the National Academy of Engineering, which corresponds to the mutually inspiring cycle in the two nations.
The basic principle of industrial ecology suggests substitution among available production factors in a closed system in order to achieve sustainable development under certain constraints. Based on this concept, Japan achieved notable energy efficiency improvements in the 1980s that can be attributed to technology substitution for energy.
Contrary to its economic stagnation in the 1980s, the USA achieved a significant economic development in the 1990s, while Japan experienced a "lost decade" due to economic stagnation. The US success can be attributed to information technology (IT) substitution for the traditional manufacturing technology, leading to a new functionality development corresponding to the requirement of an information society. However, after the bursting of the IT bubble, the USA has again been confronting the "new reality."
While the USA and Japan demonstrated contrasting success through mutual inspiration, given the new paradigm of a post-information society moving toward a ubiquitous society in the early 20th century, they need a new approach to sustaining their national innovation. Recognition of this led both countries to reexamine the broader application of the ecosystem, leading to the concept of the National Innovation Ecosystem.
Based on an empirical review of the technology policies of the USA and Japan over the last three decades with a focus on the ecosystem perspective, this paper attempts to demonstrate the hypothetical view outlined above and to provide new insights for a service-oriented economy
Contact-less characterizations of encapsulated graphene p-n junctions
Accessing intrinsic properties of a graphene device can be hindered by the
influence of contact electrodes. Here, we capacitively couple graphene devices
to superconducting resonant circuits and observe clear changes in the
resonance- frequency and -widths originating from the internal charge dynamics
of graphene. This allows us to extract the density of states and charge
relaxation resistance in graphene p-n junctions without the need of electrical
contacts. The presented characterizations pave a fast, sensitive and
non-invasive measurement of graphene nanocircuits.Comment: 4 figures, supplementary information on reques
Noise Tolerance of the BB84 Protocol with Random Privacy Amplification
We prove that BB84 protocol with random privacy amplification is secure with
a higher key rate than Mayers' estimate with the same error rate. Consequently,
the tolerable error rate of this protocol is increased from 7.5 % to 11 %. We
also extend this method to the case of estimating error rates separately in
each basis, which enables us to securely share a longer key.Comment: 26 pages, 1 figure, version 2 fills a logical gap in the proof.
Version 3 includes an upper bound on the mutual information with finete code
length by using the decoding error probability of the code. Version 4 adds a
paragraph clarifying that no previous paper has proved that the BB84 with
random privacy amplification can tolerate the 11% error rat
Measurement Invariance of the Internet Addiction Test Among Hong Kong, Japanese, and Malaysian Adolescents
There has been increased research examining the psychometric properties on the Internet Addiction Test across different ages and populations. This population-based study examined the psychometric properties using Confirmatory Factory Analysis and measurement invariance using Item Response Theory (IRT) of the IAT in adolescents from three Asian countries. In the Asian Adolescent Risk Behavior Survey (AARBS), 2,535 secondary school students (55.91% girls) in Grade 7 to Grade 13 (Mean age = 15.61 years; SD=1.56) from Hong Kong (n=844), Japan (n=744), and Malaysia (n=947) completed a survey on their Internet use that incorporated the IAT scale. A nested hierarchy of hypotheses concerning IAT cross-country invariance was tested using multi-group confirmatory factor analysis. Replicating past finding in Hong Kong adolescents, the construct of IAT is best represented by a second-order three-factor structure in Malaysian and Japanese adolescents. Configural, metric, scalar, and partial strict factorial invariance was established across the three samples. No cross-country differences on Internet addiction were detected at latent mean level. This study provided empirical support to the IAT as a reliable and factorially stable instrument, and valid to be used across Asian adolescent populations
Mapping functions and critical behavior of percolation on rectangular domains
The existence probability and the percolation probability of the
bond percolation on rectangular domains with different aspect ratios are
studied via the mapping functions between systems with different aspect ratios.
The superscaling behavior of and for such systems with exponents
and , respectively, found by Watanabe, Yukawa, Ito, and Hu in [Phys. Rev.
Lett. \textbf{93}, 190601 (2004)] can be understood from the lower order
approximation of the mapping functions and for and ,
respectively; the exponents and can be obtained from numerically
determined mapping functions and , respectively.Comment: 17 pages with 6 figure
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