16,655 research outputs found
Computing by nowhere increasing complexity
A cellular automaton is presented whose governing rule is that the Kolmogorov
complexity of a cell's neighborhood may not increase when the cell's present
value is substituted for its future value. Using an approximation of this
two-dimensional Kolmogorov complexity the underlying automaton is shown to be
capable of simulating logic circuits. It is also shown to capture trianry logic
described by a quandle, a non-associative algebraic structure. A similar
automaton whose rule permits at times the increase of a cell's neighborhood
complexity is shown to produce animated entities which can be used as
information carriers akin to gliders in Conway's game of life
Vacuum structure and effective potential at finite temperature: a variational approach
We compute the effective potential for theory with a squeezed
coherent state type of construct for the ground state. The method essentially
consists in optimising the basis at zero and finite temperatures. The gap
equation becomes identical to resumming the infinite series of daisy and super
daisy graphs while the effective potential includes multiloop effects and
agrees with that obtained through composite operator formalism at finite
temperature.Comment: 15 pages, Revtex, No figures, to appear in Jou. of Phys.G(Nucl. and
Part. Phys.
Chiral Symmetry Breaking and Pion Wave Function
We consider here chiral symmetry breaking through nontrivial vacuum structure
with quark antiquark condensates. We then relate the condensate function to the
wave function of pion as a Goldstone mode. This simultaneously yields the pion
also as a quark antiquark bound state as a localised zero mode in vacuum. We
illustrate the above with Nambu Jona-Lasinio model to calculate different
pionic properties in terms of the vacuum structure for breaking of exact or
approximate chiral symmetry, as well as the condensate fluctuations giving rise
to mesons.Comment: latex, revtex, 16 page
Force-induced desorption of a linear polymer chain adsorbed on an attractive surface
We consider a model of self-avoiding walk on a lattice with on-site repulsion
and an attraction for every vertex of the walk visited on the surface to study
force-induced desorption of a linear polymer chain adsorbed on an attractive
surface and use the exact enumeration technique for analyzing how the critical
force for desorption depends on the temperature. The curve
gives the boundary separating the adsorbed phase from the desorbed phase. Our
results show that in two dimensions where surface is a line the force
increases monotonically as temperature is lowered and becomes almost constant
at very low temperatures. In case of three-dimensions we, however, find
re-entrance, i. e. goes through a maximum as temperature is lowered.
The behaviour of the polymer chain at different values of temperature and force
is examined by calculating the probability distribution of the height from the
surface of the vertex at which external force is applied.Comment: Preprint 15 pages with 8figures and two tables. The file table-2d.ps
and table-3d.ps lists C_N(Ns,h) for given N with all possible Ns and h in two
and three dimension
A microfluidic device for the study of the orientational dynamics of microrods
We describe a microfluidic device for studying the orientational dynamics of
microrods. The device enables us to experimentally investigate the tumbling of
microrods immersed in the shear flow in a microfluidic channel with a depth of
400 mu and a width of 2.5 mm. The orientational dynamics was recorded using a
20 X microscopic objective and a CCD camera. The microrods were produced by
shearing microdroplets of photocurable epoxy resin. We show different examples
of empirically observed tumbling. On the one hand we find that short stretches
of the experimentally determined time series are well described by fits to
solutions of Jeffery's approximate equation of motion [Jeffery, Proc. R. Soc.
London. 102 (1922), 161-179]. On the other hand we find that the empirically
observed trajectories drift between different solutions of Jeffery's equation.
We discuss possible causes of this orbit drift.Comment: 11 pages, 8 figure
Effectiveness of Reactive Power Capability of Photo Voltaic Inverters to Maintain Voltage Profile in a Residential Distribution Feeder
Large penetration of rooftop PVs has resulted in unacceptable voltage profile in many residential distribution feeders. Limiting real power injection from PVs to alleviate over voltage problem is not feasible due to loss of green power and hence corresponding revenue loss. Reactive capability of the PV inverter can be a solution to address over voltage and voltage dip problems to some extent. This paper proposes an algorithm to utilize reactive capability of PV inverters and investigate their effectiveness for voltage improvement based on R/X ratio of the feeder. The length and loading level of the feeder for a particular R/X ratio to have acceptable voltage profile is also investigated. This can be useful for suburban design and residential distribution planning. Furthermore, coordination among different PVs using residential smart meters via a substation based controller is also proposed
Understanding the Persistence of Caste: A Commentary on Cotterill, Sidanius, Bhardwaj and Kumar (2014)
We contextualise Cotterill, Sidanius, Bhardwaj, and Kumar’s (2014) paper within a broader literature on caste and collective mobilisation. Cotterill and colleagues’ paper represents a fresh and timely attempt to make sense of the persistence of caste from the perspective of Social Dominance Theory. Cotterill and colleagues, however, do not examine caste differences in the endorsement of karma, and take behavioural asymmetry among lower castes for granted. Cotterill and colleagues also adhere to a Varna model of the caste system that arguably is simplistic and benefits the upper castes of Indian society. We caution that emphasising behavioural asymmetry and endorsing the Varna model might further stigmatise lower castes, especially Dalits, and feed into a conformity bias already predominant in caste-related psychological research. We argue that the conceptualisation and operationalisation of Right-Wing Authoritarianism, Social Dominance Orientation and legitimising myths in the Indian context needs to take into account the particular meaning and functions of these constructs in specific intergroup contexts, and for identity positions salient within these contexts. We contend that any examination aimed at better understanding the nature of social hierarchy and oppression within the caste system and Indian society in general remains inconclusive without including a focus on the construction and contestation of social categories and social identities
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