712 research outputs found
A Note on String Field Theory in the Temporal Gauge
In this note, we review the recent developments in the string field theory in
the temporal gauge. (Based on a talk presented by N.I. in the workshop {\it
Quantum Field Theory, Integrable Models and Beyond}, Yukawa Institute for
Theoretical Physics, Kyoto University, 14-18 February 1994.)Comment: 20 pages, KEK-TH-411, LaTex fil
High Quality Factor Silicon Cantilever Driven by PZT Actuator for Resonant Based Mass Detection
A high quality factor (Q-factor) piezoelectric lead zirconat titanate (PZT)
actuated single crystal silicon cantilever was proposed in this paper for
resonant based ultra-sensitive mass detection. Energy dissipation from
intrinsic mechanical loss of the PZT film was successfully compressed by
separating the PZT actuator from resonant structure. Excellent Q-factor, which
is several times larger than conventional PZT cantilever, was achieved under
both atmospheric pressure and reduced pressures. For a 30 micrometer-wide 100
micrometer-long cantilever, Q-factor was measured as high as 1113 and 7279
under the pressure of 101.2 KPa and 35 Pa, respectively. Moreover, it was found
that high-mode vibration can be realized by the cantilever for the pursuit of
great Q-factor, while support loss became significant because of the increased
vibration amplitude at the actuation point. An optimized structure using
node-point actuation was suggested then to suppress corresponding energy
dissipation.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Stochastic Hamiltonian for Non-Critical String Field Theories from Double-Scaled Matrix Models
We present detailed discussions on the stochastic Hamiltonians for
non-critical string field theories on the basis of matrix models. Beginning
from the simplest case, we derive the explicit forms of the Hamiltonians
for the higher critical case (which corresponds to ) and for the
case , directly from the double-scaled matrix models. In particular, for
the two-matrix case, we do not put any restrictions on the spin configurations
of the string fields. The properties of the resulting infinite algebras of
Schwinger-Dyson operators associated with the Hamiltonians and the derivation
of the Virasoro and algebras therefrom are also investigated. Our results
suggest certain universal structure of the stochastic Hamiltonians, which might
be useful for an attempt towards a background independent string field theory.Comment: 70 pages, LaTeX, typographical errors are corrected, to be published
in Phys. Rev.
Loop Equations for + and - Loops in c = 1/2 Non-Critical String Theory
New loop equations for all genera in non-critical string
theory are constructed. Our loop equations include two types of loops, loops
with all Ising spins up (+ loops) and those with all spins down ( loops).
The loop equations generate an algebra which is a certain extension of
algebra and are equivalent to the constraints derived before in the
matrix-model formulation of 2d gravity. Application of these loop equations to
construction of Hamiltonian for string field theory is
considered.Comment: 21 pages, LaTex file, no figure
Biocultural Practices during the Transition to History at the Vat Komnou Cemetery, Angkor Borei, Cambodia
Mainland Southeast Asia underwent dramatic changes after the mid-first millennium B.C.E., as its populations embraced new metallurgical and agricultural technologies. Southeast Asians transformed their physical and social environments further through their participation in international maritime trade networks. Early state formation characterized much of the mainland by the mid-first millennium C.E. We examined a protohistoric (200 B.C.E.–200 C.E.) skeletal sample from the Vat Komnou cemetery at Angkor Borei in the Mekong Delta (southern Cambodia) to understand the health impacts of this changing environment. Degenerative joint disease patterns indicate a distinct sexual division of labor. Although intentional dental filing was practiced, its impact on oral-dental health could not be determined. Dental pathologies suggest a mixed diet with more fibrous foods and a lower reliance on soft, processed agricultural foods. A broad-spectrum diet and varied use of the local environment are inferred from the faunal evidence. Stable isotope ratios indicate a relatively greater reliance on fish and estuarine dietary resources than on terrestrial protein. Affinities with other groups in the region are suggested by the cultural practices of the relatively tall, healthy inhabitants from Vat Komnou
Multiple episodes of ice loss from the Wilkes Subglacial Basin during the Last Interglacial
The Last Interglacial (LIG: 130,000-115,000 years ago) was a period of warmer global mean temperatures and higher and more variable sea levels than the Holocene (11,700-0 years ago). Therefore, a better understanding of Antarctic ice-sheet dynamics during this interval would provide valuable insights for projecting sea-level change in future warming scenarios. Here we present a high-resolution record constraining ice-sheet changes in the Wilkes Subglacial Basin (WSB) of East Antarctica during the LIG, based on analysis of sediment provenance and an ice melt proxy in a marine sediment core retrieved from the Wilkes Land margin. Our sedimentary records, together with existing ice-core records, reveal dynamic fluctuations of the ice sheet in the WSB, with thinning, melting, and potentially retreat leading to ice loss during both early and late stages of the LIG. We suggest that such changes along the East Antarctic Ice Sheet margin may have contributed to fluctuating global sea levels during the LIG
Exact Renormalization Group and Loop Equation
We propose a gauge invariant formulation of the exact renormalization group
equation for nonsupersymmetric pure U(N) Yang-Mills theory, based on the
construction by Tim Morris. In fact we show that our renormalization group
equation amounts to a regularized version of the loop equation, thereby
providing a direct relation between the exact renormalization group and the
Schwinger-Dyson equations. We also discuss a possible implication of our
formulation to the holographic correspondence of the bulk gravity and the
boundary gauge theory.Comment: 13 pages, Latex, References added. An error in eq. (6) fixed and a
few corrrections accordingly. Results unchange
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