Nonreciprocity as a generic route to traveling states

We examine a non-reciprocally coupled dynamical model of a mixture of two diffusing species. We demonstrate that nonreciprocity, which is encoded in the model via antagonistic cross diffusivities, provides a generic mechanism for the emergence of traveling patterns in purely diffusive systems with conservative dynamics. In the absence of non-reciprocity, the binary fluid mixture undergoes a phase transition from a homogeneous mixed state to a demixed state with spatially separated regions rich in one of the two components. Above a critical value of the parameter tuning non-reciprocity, the static demixed pattern acquires a finite velocity, resulting in a state that breaks both spatial and time translational symmetry, as well as the reflection parity of the static pattern. We elucidate the generic nature of the transition to traveling patterns using a minimal model that can be studied analytically. Our work has direct relevance to nonequilibrium assembly in mixtures of chemically interacting colloids that are known to exhibit non-reciprocal effective interactions, as well as to mixtures of active and passive agents where traveling states of the type predicted here have been observed in simulations. It also provides insight on transitions to traveling and oscillatory states seen in a broad range of nonreciprocal systems with non-conservative dynamics, from reaction-diffusion and prey-predators models to multispecies mixtures of microorganisms with antagonistic interactions.Comment: 8 pages, 3 figure

Enhanced diffusion and ordering of self-propelled rods

Starting from a minimal physical model of self propelled hard rods on a substrate in two dimensions, we derive a modified Smoluchowski equation for the system. Self -propulsion enhances longitudinal diffusion and modifies the mean field excluded volume interaction. From the Smoluchowski equation we obtain hydrodynamic equations for rod concentration, polarization and nematic order parameter. New results at large scales are a lowering of the density of the isotropic-nematic transition and a strong enhancement of boundary effects in confined self-propelled systems.Comment: 4 pages, 2 figure

The impact of the national innovation systems on the flow and benefits of foreign direct investment to national economics.

In the increasingly globalising economy, the flow of foreign direct investment(FDI) is seen as an important source for achieving greater and faster economic growth, particularly in the emerging market economies and other developing countries. Studies on FDI focus on different aspects such as impact of FDI on economic growth, its linkages to foreign trade, its contribution to technology diffusion and human capital formation in the local economy, its social and environmental impacts on host countries, the factors that determine different level of flow of FDI to different countries, the link between FDI and international production, trade and technology development. Such studies mainly highlighted that there are benefits as well as costs from FDI for the host countries (e.g. OECD, 2002; Wei, 2005; Chakraborty and Basu, 2002; Rajan, 2005). The benefits include technology spillovers, human capital formation, international trade integration, competitive environment, and enterprise development, and so on. The costs include balance of payment problems due to repatriation of profit, failure to link with local communities, negative impact on local environment, social destabilisation due to rapid commercialisation, impact on competition in national market, host country failing to benefit from technology and know how transfer, and loss of political sovereignty. Although it is found that the overall benefits are greater than costs, it is pointed out that benefits of FDI are not automatic, particularly for developing countries. It is suggested that these countries need to pursue appropriate policy regimes and should have “a basic level of development”. Various studies suggest that not only the volume and nature of FDI flow varies greatly across the emerging and less developed economies, but also their ability to absorb and benefit from them and how effectively they use FDI to enhance their national productive systems varies greatly. In this paper we would argue that this capacity is directly related to the degree of functioning of an economy’s national innovation system. If FDI is one key route for the introduction of knowledge, technology or innovation that is new to a national economy, it matters a lot how the network of institutions, ideas, policies, strategies, agents and incentives are organised, and work in tandem with logic and coherence and thus communicate and interact effectively to bring transformation. How well the latter are organised, interfacing the elements of the social-economic, productive and knowledge, intersectoralising the sectors and forging interdependent agents and structures is a question of the type of national innovation system (NIS) in place. FDI is not negative or positive a priori. Its role as positive or negative should emerge in relation to specific contexts and requires contextualising it within given national systems of innovation. And we propose that the weakness or strength of the system of innovation influences whether FDI’s contribution is negative or positive. A study of FDI in relation to how different national systems with varied capacities and characteristics or the strengths and weaknesses inherent in their NIS deal and cope with FDI can yield fresh policy insight on the type of changes that must take priority to benefit from flows of FDI. In this paper we analyse the nature of the flow of FDI in some selected emerging market economies such as China, India, South Africa and few smaller economies and its impact on these national economies. We analyse the volume, nature and characteristics of the FDI inflow in these countries and whether and how NIS has shaped the flow and the impact of FDI on these economies. We focus on the issue of managing and absorbing FDI to enhance national productive systems rather than whether FDI is positive or negative

RVB gauge theory and the Topological degeneracy in the Honeycomb Kitaev model

We relate the Z$_2$ gauge theory formalism of the Kitaev model to the SU(2) gauge theory of the resonating valence bond (RVB) physics. Further, we reformulate a known Jordan-Wigner transformation of Kitaev model on a torus in a general way that shows that it can be thought of as a Z$_2$ gauge fixing procedure. The conserved quantities simplify in terms of the gauge invariant Jordan-Wigner fermions, enabling us to construct exact eigen states and calculate physical quantities. We calculate the fermionic spectrum for flux free sector for different gauge field configurations and show that the ground state is four-fold degenerate on a torus in thermodynamic limit. Further on a torus we construct four mutually anti-commuting operators which enable us to prove that all eigenstates of this model are four fold degenerate in thermodynamic limit.Comment: 12 pages, 3 figures. Added affiliation and a new section, 'Acknowledgements'.Typos correcte

An Electronic Model for CoO2CoO_2 layer based systems: Chiral RVB metal and Superconductivity

Takada et al. have reported superconductivity in layered Na__x CoO_2.yH_2O ($T_c \approx5 K$) and more recently Wen et al. in $A_xCoO_{2+\delta}$ ($A = Na,K$)(\tc$\approx~31 K$). We model a reference neutral \cob layer as an orbitally non-degenerate spin-\half antiferromagnetic Mott insulator on a triangular lattice and Na__x CoO_2.yH_2O and $A_xCoO_{2+\delta}$ as electron doped Mott insulators described by a t-J model. It is suggested that at optimal doping chiral spin fluctuations enhanced by the dopant dynamics leads to a d-wave superconducting state. A chiral RVB metal, a PT violating state with condensed RVB gauge fields, with a possible weak ferromagnetism and low temperature p-wave superconductivity are also suggested at higher dopings.Comment: 4 pages of LaTex file, 6 figures in eps files. Typos and minor corrections mad

Influence of national system of innovation on the trajectory of foreign direct investment.

The ability to absorb and use effectively FDI flows by countries to enhance their national productive systems is directly related to the degree of functioning of an economy’s national innovation system. We develop a heuristic NSI-FDI framework that proposed three types of NSIs (well functioning/strong, relatively well functioning, and weak) in relation with three types of corresponding FDI outcomes (High-end, Medium or Average, and Low-end). We then selected both large and small developing economies -- China, India, South Africa, Ghana, Ethiopia, Tanzania, and Zambia with both different NSIs and FDI flows. The countries were differentiated with respect to core differences in the types of NSIs. Using descriptive data we analysed the nature of FDI flows and their impacts or outcomes in these countries and showed that the characteristics of the NSI in these countries largely shaped the flow and the impact of FDI on these economies

Foreign direct investment and internationalization of R&D: the case of BRICS economies.

Foreign direct investment (FDI) is increasingly seen as an important source for achieving greater and faster economic growth and technology accumulation in many developing countries. There has been a good number of studies over the years on different aspects of FDI such as its impact on economic growth, its contribution to technology diffusion and human capital formation in the local economy, the factors that determine different level of flow of FDI to different countries, trade and technology development, and its costs and benefits (e.g. OECD, 2002; Wei, 2005; Chakraborty and Basu, 2002; Rajan, 2005). Some of these studies suggest that not only the volume and nature of FDI flow varies greatly across the emerging and less developed economies, but also their ability to absorb and benefit from them and how effectively they use FDI to enhance their national productive systems varies greatly. In this context, what is interesting to study is the increasing trend of locating and organising R&D by foreign companies in emerging market economies through FDI, particularly in the large emerging economies in Asia such as China and India. It appears that increasingly internationalization of R&D is considered an important vehicle to maintain competitiveness in the globalised economic environment. Because of this the attitude of large multinational corporations and other businesses have been changing towards the types of R&D operations being carried out outside their home base. This is illustrated by the development in recent years particularly in China and India, and to a lesser extent in other emerging market economies. Increasingly, not only the volume of R&D has increased but also the degree of complexity and higher value added. What this may mean is that a country that has a relatively functioning NSI can attract FDI in R&D that often TNCs were not willing to engage in the past. It seems clear that FDI for R & D and knowledge transfer means that the relationship between the TNCs and the local subsidiaries is changing. This has implication for economic development. The change may not be because the TNCs have changed their main logic for moving across the world, it may be related to the new stature achieved by continental-sized economies such as India and China. In other words as the NIS’ in these countries are relatively stronger and becoming more mature, they are able to manage and absorb the FDI flow better for achieving their socio-economic development goals. In this paper we will examine and analyse the domestic and external factors that are contributing to the increasing volume and complexity in international R&D inflow. We would argue that the capacity to attract international R&D is directly related to the degree of functioning of an economy’s national innovation system. That is, the weakness or strength of NIS influences the nature and volume of international R&D inflow through FDI. For this, we take the case of BRICS economies – Brazil, India, China and South Africa (excluding Russia). We aim to generate comparative insights by taking into account differences in the NIS across these countries and how that impact on the nature and shape of FDI in R&D in these economies. In this paper we also attempt to examine whether there are emerging sectors that are being opened by BRICS economies with changes to regulatory arrangements and incentives to attract international R&D flow thorough FDI. Conversely, we would also attempt to examine it from the side of the companies, corporations and their home base constraints that impel them to engage in internationalization of R&D through FDI. In other words, we would attempt to understand whether FDI is playing a significant role in specific sectors such as Telecom or IT in BRICS countries, particularly in China and India contributing to a dramatic shift in the world economy

Can the relative strength of the national systems of innovation mitigate the severity of the global recession on the BRICS?

The research question we wish to investigate is the degree to which different countries with differing levels of NSI strength and weakness cope in mitigating some of the adverse impacts of the recession. In general during the recession confidence declines or what Keynes calls the „animal spirit‟. Creative destruction is heightened as firms destroyed need to find other ways of recreating their economic activities. Exports and imports change. Investment from abroad declines and consumers afraid of the recession save or even hoard. Such a state is likely to impact those who are absorbing FDI and exporting to the heartland of the current recession which is the US market. China and India both export mainly hardware and software related goods and services respectively to this market where reduction in demand has resulted in company closures and unemployment. Even free trade has been challenged with protectionist and nationalist rhetoric on the rise during this recession. Given a recession that has affected the entire world economy and its constituent parts, both the way the recession impacts on different national economies and the ability of national economies to mitigate the recession are likely to be different. This paper concentrates on the latter not on the former per se. We examine what mitigating capability different national innovation systems have in relation to dealing with and responding to the current world financial and economic crises. The hypothesis we would like to test with descriptive comparative data is how far the relative strength or weakness of the NSI is capable of mitigating the adverse impact of the recession. We assume that that the nature and degree of impact of the recession across countries are likely to be different. In this paper we would like to take only the NSI factor in trying to account how such differences due to the individual characteristics of NSIs across different countries mitigate recessionary impact on given economies. For this, we propose to examine selected sectors from selected emerging economies such as China, India, Brazil and South Africa (BRICS excluding Russia) to estimate mitigating capabilities of different NSIs