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 $\epsilon$-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 $Z_2$ Gauss-law type constraints, which in turn imply emergent $Z_2$ 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