1,825 research outputs found
Disorder-driven destruction of a non-Fermi liquid semimetal via renormalization group
We investigate the interplay of Coulomb interactions and
short-range-correlated disorder in three dimensional systems where absent
disorder the non-interacting band structure hosts a quadratic band crossing.
Though the clean Coulomb problem is believed to host a 'non-Fermi liquid'
phase, disorder and Coulomb interactions have the same scaling dimension in a
renormalization group (RG) sense, and thus should be treated on an equal
footing. We therefore implement a controlled -expansion and apply it
at leading order to derive RG flow equations valid when disorder and
interactions are both weak. We find that the non-Fermi liquid fixed point is
unstable to disorder, and demonstrate that the problem inevitably flows to
strong coupling, outside the regime of applicability of the perturbative RG. An
examination of the flow to strong coupling suggests that disorder is
asymptotically more important than interactions, so that the low energy
behavior of the system can be described by a non-interacting sigma model in the
appropriate symmetry class (which depends on whether exact particle-hole
symmetry is imposed on the problem). We close with a discussion of general
principles unveiled by our analysis that dictate the interplay of disorder and
Coulomb interactions in gapless semiconductors, and of connections to many-body
localized systems with long-range interactions.Comment: 15 pages, 4 figure
International trade, R&D spillovers and productivity : evidence from Indian manufacturing industry
This paper examines the effect of trade facilitated R&D spillovers
on the productivity of manufacturing firms in India. Though developing
countries are considered as the major beneficiaries of trade facilitated
R&D spillovers, detailed empirical investigations in their context are
lacking. The paper distinguishes R&D spillovers into two types and
examines their effect on productivity. It also considers the intersectoral
variation in productivity effect and the importance of firms' investment
in R&D, imported technology and plant and machinery in enhancing
the effect on productivity. The paper uses firm level panel data and an
improved estimation method. It shows that R&D spillovers have a
significant effect on productivity and there exists intersectoral variation
with greater contribution to productivity in technology intensive
industries. The paper also shows that firms' investment in R&D and plant
and machinery are enhancing the productivity effect of R&D spillovers.
Keywords: R&D Spillover, trade, manufacturing industry, productivity
JEL Classification: F43, L6, O33
Financial crisis and Kerala economy
The study examines the trends in export, foreign remittances,
credit availability, and tourism in the context of Kerala economy against
the background of global financial crisis and subsequent global
recession. Kerala is considered to be highly vulnerable to a crisis like
this because of its greater integration with the rest of the world. The
study shows that there are some reasons to believe that the financial
crisis affected Kerala economy adversely by slowing down export and
tourism in the year 2008-09 which witnessed the worst impact of the
crisis.
JEL Classification: E32, F15, F44
Key Words: Global Financial Crisis, India, Kerala, export
Economic reforms and technical efficiency : firm level evidence from selected industries in India
This paper analyses the performance of the manufacturing firms
in some selected industries in terms of their technical efficiency against
the background of the industrial and trade policy reforms introduced in
India since 1991. A stochastic frontier production function and an
associated inefficiency model are used to measure time varying firm
specific technical efficiency. We define technical change as the shift of
the best practice production frontier and technical inefficiency change
as the movement within the best practice technology. The results show
that all the industries considered registered a higher rate of technical
progress in the post reform period along with a decline in the level of
technical efficiency. The effect of change in the policy environment on
technical efficiency varies among industries. The study also found that
firms’ involvement in the international trade through export and import
of raw materials and technology has a positive effect on technical
efficiency.
Key words: India, Manufacturing, Technical Efficiency, Economic
Reforms.
JEL Classifications: D24, F13, L60, O3
Recoverable Information and Emergent Conservation Laws in Fracton Stabilizer Codes
We introduce a new quantity, that we term recoverable information, defined
for stabilizer Hamiltonians. For such models, the recoverable information
provides a measure of the topological information, as well as a physical
interpretation, which is complementary to topological entanglement entropy. We
discuss three different ways to calculate the recoverable information, and
prove their equivalence. To demonstrate its utility, we compute recoverable
information for fracton models using all three methods where appropriate. From
the recoverable information, we deduce the existence of emergent
Gauss-law type constraints, which in turn imply emergent conservation
laws for point-like quasiparticle excitations of an underlying topologically
ordered phase.Comment: Added additional cluster model calculation (SPT example) and a new
section discussing the general benefits of recoverable informatio
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