4,661 research outputs found
Translocality and a Duality Principle in Generally Covariant Quantum Field Theory
It is argued that the formal rules of correspondence between local
observation procedures and observables do not exhaust the entire physical
content of generally covariant quantum field theory. This result is obtained by
expressing the distinguishing features of the local kinematical structure of
quantum field theory in the generally covariant context in terms of a
translocal structure which carries the totality of the nonlocal kinematical
informations in a local region. This gives rise to a duality principle at the
dynamical level which emphasizes the significance of the underlying translocal
structure for modelling a minimal algebra around a given point. We discuss the
emergence of classical properties from this point of view.Comment: 12 pages. To appear in Classical Quantum Gravit
A regularizing commutant duality for a kinematically covariant partial ordered net of observables
We consider a net of *-algebras, locally around any point of observation,
equipped with a natural partial order related to the isotony property. Assuming
the underlying manifold of the net to be a differentiable, this net shall be
kinematically covariant under general diffeomorphisms. However, the dynamical
relations, induced by the physical state defining the related net of (von
Neumann) observables, are in general not covariant under all diffeomorphisms,
but only under the subgroup of dynamical symmetries.
We introduce algebraically both, IR and UV cutoffs, and assume that these are
related by a commutant duality. The latter, having strong implications on the
net, allows us to identify a 1-parameter group of the dynamical symmetries with
the group of outer modular automorphisms.
For thermal equilibrium states, the modular dilation parameter may be used
locally to define the notions of both, time and a causal structure.Comment: LaTeX, to appear in: Proc. XXI. Int. Sem. on Group Theor. Methods,
Goslar (1996), eds. Doebner et a
Analysis of factor costs contribution change for fingerling production of kutum fish (Rutilus frisii kutum Kamensky, 1901) in Iran
Contribution change of factor costs analysis may help managers in decision making and in adjusting to changes. Over the last two decades, production and enhancement of kutum fingerlings have increased in Iran, reaching to more than 229 million fingerlings by 2005, but declined to 187 million from 2005 to 2008. Over the years 2002-2006, a study of fingerling production costs for kutum fish was carried out. For this purpose, a questionnaire was prepared and filled out by an expert team using data available in kutum hatcheries for fingerling production and other related departments in Iranian Fisheries Organization. Among various expenditures, the contribution cost of labor with the greatest share averaged almost 40% of total costs, followed by feed and fertilizer which averaged more than 15%. Results show, in average, the production cost of a single kutum fingerling was 100 IR Rials (US 0.014) in 2004 and 157 IR Rials (US$ 0.017) in 2005. Yearly growth of a single fingerling was averaged more than 50% from 2001-2005. The results clearly indicated that over the years 2001-2005 the contribution cost of labor and "feed and fertilizer" declined, but it increased for "water and energy" and Miscellaneous. Overall, the costs sensitivity analysis of hatcheries production of kutum fingerling shows labor is the most sensitive, and a 50% decrease of this item, decreases the total cost by almost 20%
Comparative analysis of carp farming costs in Iran, in 1996 and 2001
Carp is one of the most widely cultivated warm water fish, which has been introduced into many countries. It is essential for the manager of a carp farm to know the production costs and their evolution, showing the main inputs on which the cost reduction is worth effort. In Iran, carp farming is mainly based on common carp, silver carp, grass carp, and bighead carp, which were often reared in poly culture. Carp farming production reached a peak in 2006 with production of more than 77,000 tones. The characteristics of the carp farming industry in the main fish farming provinces, (overall more than 90% of total carp production) are considerably different. In years 1996 and 2001, a study of yield production, factor costs and profitability of farmed carp was carried out to help clarify carp production costs and their difference between the provinces. 153 farms in 1996 and 101 farms in 2001, overall, a total of 254 farms from the main carp farming provinces, including; Guilan, Mazandaran and Khuzestan were randomly selected, classified and studied. Results showed that the various producer provinces have different cost structures. Overall, feed and fertilizer with the highest level of variation accounted for 45% of total costs in 1996, declined to 23% in 2001. However, on average, cost of seed and labor increased from 7% and 10% to 23% and 17% of total costs over the 1996 and 2001, respectively. On average, benefit-cost ratio and the rate of farm income were closely related to location suggesting that farmers practiced more efficiently and have better conditions in Guilan in 1996, resulting in higher farm income per ha and per kg, changing to better conditions and more efficient by Mazandaran province in 2001. Overall, in the three main provinces, rate of farm income from an average of 20% in 1996, declined to 12% in 2001
Duality, Time-asymmetry and the Condensation of Vacuum
A variant of the divergence theory for vacuum-condensation developed in a
previous communication is analyzed from the viewpoint of a 'time' asymmetric
law in vacuum. This law is found to establish a substantial distinction between
dynamically allowed vacuum-configurations related by signature changing duality
transformations.Comment: 6 pages, latex fil
Mechanism for a Decaying Cosmological Constant
A mechanism is introduced to reduce a large cosmological constant to a
sufficiently small value consistent with observational upper limit. The basic
ingradient in this mechanism is a distinction which has been made between the
two unit systems used on cosmology and particle physics. We have used a
conformal invariant gravitational model to define a particular conformal frame
in terms of the large scale properties of the universe. It is then argued that
the contributions of mass scales in particle physics to the vacuum energy
density should be considered in a different conformal frame. In this manner a
cancellation mechanism is presented in which the conformal factor plays a key
role to relax the large effective cosmological constant.Comment: 6 pages, no figur
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