18,797 research outputs found
Understanding complexity: the curvilinear relationship between environmental performance and firm performance
The nature of the relationship between environmental
performance (EP) and firm performance (FP) of
corporations is a long standing and contentious issue in the
literature. This study is intended to advance this debate by
arguing for the existence of curvilinear relationship and
empirically testing the same using survey data on UK
manufacturing firms. FP is captured in terms of growth in
sales and market share. Our results show evidence for a
quadratic relationship—as firms improve their EP, they
seem to achieve much higher levels of FP. These results are
consistent with the resource-based view of a firm; as firms
engage in EP activities, they are able to gain inimitable
knowledge that helps in further learning to further
improve performance. Based on our results, we suggest that
new studies focus on strategies to extend the period of
increasing returns and maximizing the benefits of the
positive association between EP and FP
Defining Recursive Predicates in Graph Orders
We study the first order theory of structures over graphs i.e. structures of
the form () where is the set of all
(isomorphism types of) finite undirected graphs and some vocabulary. We
define the notion of a recursive predicate over graphs using Turing Machine
recognizable string encodings of graphs. We also define the notion of an
arithmetical relation over graphs using a total order on the set
such that () is isomorphic to
().
We introduce the notion of a \textit{capable} structure over graphs, which is
one satisfying the conditions : (1) definability of arithmetic, (2)
definability of cardinality of a graph, and (3) definability of two particular
graph predicates related to vertex labellings of graphs. We then show any
capable structure can define every arithmetical predicate over graphs. As a
corollary, any capable structure also defines every recursive graph relation.
We identify capable structures which are expansions of graph orders, which are
structures of the form () where is a partial order. We
show that the subgraph order i.e. (), induced subgraph
order with one constant i.e. () and an expansion
of the minor order for counting edges i.e. ()
are capable structures. In the course of the proof, we show the definability of
several natural graph theoretic predicates in the subgraph order which may be
of independent interest. We discuss the implications of our results and
connections to Descriptive Complexity
Superadiabatic Control of Quantum Operations
Adiabatic pulses are used extensively to enable robust control of quantum
operations. We introduce a new approach to adiabatic control that uses the
superadiabatic quality or -factor as a performance metric to design robust,
high fidelity pulses. This approach permits the systematic design of quantum
control schemes to maximize the adiabaticity of a unitary operation in a
particular time interval given the available control resources. The interplay
between adiabaticity, fidelity and robustness of the resulting pulses is
examined for the case of single-qubit inversion, and superadiabatic pulses are
demonstrated to have improved robustness to control errors. A numerical search
strategy is developed to find a broader class of adiabatic operations,
including multi-qubit adiabatic unitaries. We illustrate the utility of this
search strategy by designing control waveforms that adiabatically implement a
two-qubit entangling gate for a model NMR system.Comment: 10 pages, 9 figure
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